Aspects of life-history strategy of Marcusenius senegalensis (Pisces: Osteoglossiformes: Mormyridae; Steindachner, 1870) from Niger River in Northern Benin
Marcusenius senegalensis (Steindachner, 1870) is the dominant mormyrid in Niger River in Northern-Benin where this fish species constitutes an important component of artisanal fisheries. The current study documented the reproductive biology of M. senegalensis in order to contribute to management and sustainable exploitation. Monthly samplings were conducted between February 2015 and July 2016 using gillnets, cast net, and seine. Males dominated the population with a sex ratio of 1:0.96 in favor of males. Sizes at first sexual maturity were 167.89 mm-TL for males and 163.81 mm-TL for females. Monthly gonadosomatic index (GSI) averaged 0.12 ± 0.09 for males and 1.32 ± 1.56 for female and peaks recorded indicated that spawning occured from June to September. Fecundity were moderate to low (844 – 12,643 eggs) and significantly (p < 0.05) increased with total length and body weight. Thespecies showed egg diameters varying between 0.21 and to 1.77 mm and ovaries comprised oocytes at all stages of maturation indicating that M. senegalensis displayed a multi-spawning behavior. Marcuseniussenegalensis exhibited a demographic strategy between r and K, yet more inclined towards K-selected strategy. In Niger River, reproduction grounds were being severely degraded affecting recruitment and stocks. The current findings are valuable data to design a species management scheme that should includes spawning ground protection, species conservation and valorization and fisheries/aquaculture development.
Species Diversity of Mangroves in Catarman, Northern Samarijtsrd
This study identified mangrove species in Catarman, Northern Samar which was categorized into families, genera and species. The researcher utilized transect line plot to determine the species composition of mangroves. A 10m x 10m plot was laid along calibrated rope were mangrove species were located. The mangroves were identified and classified taxonomically up to the species level using the Field Guide Manual to Philippine Mangroves. The researcher able to sampled nine true mangrove species and eight mangrove associates from the study area. Beberlie L. Medrano-Dangkeo "Species Diversity of Mangroves in Catarman, Northern Samar" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-1 , December 2020, URL: https://www.ijtsrd.com/papers/ijtsrd35857.pdf Paper URL : https://www.ijtsrd.com/other-scientific-research-area/other/35857/species-diversity-of-mangroves-in-catarman-northern-samar/beberlie-l-medranodangkeo
Catch Per Unit Effort (CPUE) of Bivalves in Northwestern Bohol, PhilippinesAI Publications
Catch Per Unit Effort (CPUE) is a measure of status of marine resource in a given area. In this study, bivalve fishery information was gathered using the self-structured questionnaire. There were 61 respondents who were the registered fishermen of Calape, Tubigon and Clarin. Among the three towns it was Clarin where highest mean CPUE was observed with 1.2kg/hr/man. This was followed by Calape with 0.8kg/hr/man and lowest mean CPUE was recorded in Tubigon with 0.6kg/hr/man. High CPUE value means that there are still enough bivalve resources in the area and lowest CPUE means that these resources are endangered. Considering that, the result of this study showed that there is a need to regulate the collection of bivalves with lower wild stocks to avoid loss of these natural resources.
Interface change of seawater and freshwater on Asam – Asam Watersheds, South ...Innspub Net
Temporal change of seawater and fresh water interface in the watershed area needs scientific study on dynamics of ecosystem parameters in different seasons and analysis of satellite imagery. This research aims to assess the change of interface seawater and freshwater from the temporal estuary upstream. The study used four methods: (1) Interviews with local community respondents; determined with snowball method. (2) Secondary data obtained from the Report of Environmental Monitoring Result of Power Plant Operations of Asam – Asam in 2014 (3) Observed parameters include pH, salinity, electrical conductivity in the dry season (August), transition (October) and rainy season (December). (4) Temporal observations with the use of satellite imagery analysis with Nipah (Nypa fruticans Wurmb) as indicator. According to the respondent, seawater intrusion has occurred extremely from the estuary of Asam-Asam river to the upstream. Secondary data shows significant differences in the intake value of DHL Asam-Asam power plant (546 μ mhos/cm) with upstream intake (231 μ mhos/cm) which means the intrusion of sea water is moderate to high level. Field observations show the dry season (August 2013) interface was 12.86 miles from the estuary, whereas in transitional season (October 2013) was 12.53 miles from estuary, and rainy season (December 2013) is 5.24 km from the estuary. Satellite imagery showed the interface in 1991 was 8.13 miles from the estuary and increase upstream from 0.03 to 1.86 per year. In 2014, the interface becomes 12.88 miles from the estuary. This shows that the sea water increasingly moving toward the river. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Species Diversity of Mangroves in Catarman, Northern Samarijtsrd
This study identified mangrove species in Catarman, Northern Samar which was categorized into families, genera and species. The researcher utilized transect line plot to determine the species composition of mangroves. A 10m x 10m plot was laid along calibrated rope were mangrove species were located. The mangroves were identified and classified taxonomically up to the species level using the Field Guide Manual to Philippine Mangroves. The researcher able to sampled nine true mangrove species and eight mangrove associates from the study area. Beberlie L. Medrano-Dangkeo "Species Diversity of Mangroves in Catarman, Northern Samar" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-1 , December 2020, URL: https://www.ijtsrd.com/papers/ijtsrd35857.pdf Paper URL : https://www.ijtsrd.com/other-scientific-research-area/other/35857/species-diversity-of-mangroves-in-catarman-northern-samar/beberlie-l-medranodangkeo
Catch Per Unit Effort (CPUE) of Bivalves in Northwestern Bohol, PhilippinesAI Publications
Catch Per Unit Effort (CPUE) is a measure of status of marine resource in a given area. In this study, bivalve fishery information was gathered using the self-structured questionnaire. There were 61 respondents who were the registered fishermen of Calape, Tubigon and Clarin. Among the three towns it was Clarin where highest mean CPUE was observed with 1.2kg/hr/man. This was followed by Calape with 0.8kg/hr/man and lowest mean CPUE was recorded in Tubigon with 0.6kg/hr/man. High CPUE value means that there are still enough bivalve resources in the area and lowest CPUE means that these resources are endangered. Considering that, the result of this study showed that there is a need to regulate the collection of bivalves with lower wild stocks to avoid loss of these natural resources.
Interface change of seawater and freshwater on Asam – Asam Watersheds, South ...Innspub Net
Temporal change of seawater and fresh water interface in the watershed area needs scientific study on dynamics of ecosystem parameters in different seasons and analysis of satellite imagery. This research aims to assess the change of interface seawater and freshwater from the temporal estuary upstream. The study used four methods: (1) Interviews with local community respondents; determined with snowball method. (2) Secondary data obtained from the Report of Environmental Monitoring Result of Power Plant Operations of Asam – Asam in 2014 (3) Observed parameters include pH, salinity, electrical conductivity in the dry season (August), transition (October) and rainy season (December). (4) Temporal observations with the use of satellite imagery analysis with Nipah (Nypa fruticans Wurmb) as indicator. According to the respondent, seawater intrusion has occurred extremely from the estuary of Asam-Asam river to the upstream. Secondary data shows significant differences in the intake value of DHL Asam-Asam power plant (546 μ mhos/cm) with upstream intake (231 μ mhos/cm) which means the intrusion of sea water is moderate to high level. Field observations show the dry season (August 2013) interface was 12.86 miles from the estuary, whereas in transitional season (October 2013) was 12.53 miles from estuary, and rainy season (December 2013) is 5.24 km from the estuary. Satellite imagery showed the interface in 1991 was 8.13 miles from the estuary and increase upstream from 0.03 to 1.86 per year. In 2014, the interface becomes 12.88 miles from the estuary. This shows that the sea water increasingly moving toward the river. Get more articles at: http://www.innspub.net/volume-6-number-4-april-2015-jbes/
Confirmation records and new distribution of the red cornet fish fistularia p...MohammedWaled1
Confirmation records and new distribution of the
red cornet fish fistularia petimba lacepède, 1803
(actinopterygii: fistulariidae) in the Syrian Marine
Waters (Eastern Mediterranean)
Length-weight models and condition factors of fishes from Okpara Stream, Ouem...AI Publications
Length frequency distributions, length-weight models and condition factors of 21 dominant fish species of the Okpara stream (Oueme River) were examined in Northern-Benin in order to evaluate the well-being of these fish taxa. Samplings were made monthly from December 2015 to May 2017 with seines, gill nets hawks and a total of 9,302 individuals were collected. Fish abundance ranged from 53 individuals for Mormyrus rume to 2,818 for Hemichromis fasciatus. Standard length (SL) varied from 1.2 cm (Coptodon guineensis) to 51.8 cm (Chrysichthys nigrodigitatus). Length-weight regressions equations showed significant (p < 0.05) correlation coefficients (r) ranging between 0.4664 and 0.9949 with slopes (b) between 2.2262 and 3.7703 corresponding to isometric, positive allometric and negative allometric growths displayed by 4, 8 and 9 species, respectively. Condition factors K varied between 0.17 - 29.38 and species with higher well-being were Oreochromis niloticus with K=29.38, Hyperopisius bebe (K=20.14), Coptodon zillii (K=19.25), Mormyrus rume (K=17.13) and Sarotherodon galilaeus multifasciatus (K=16.16). A sustainable exploitation of these fishes requires an ecosystem restoration scheme including habitat protection, species conservation and an ecological follow-up of the Okpara stream.
First record of invasive croaking gourami, Trichopsis vittata (Cuvier 1831) ...Shoaibe H T Shefat
this study aimed to investigate the biology, source of introduction, impacts on native fish biodiversity and spreading pattern of this croaking gourami to develop proper conservation
strategy and implementation of a systematic approach.
Research Proposal - Are the Adélie penguin, Pygoscelis adeliae, populations w...ElizabethHowarth1
Rational - The focus on this study is to evaluate how the population size and health of Adélie penguin, Pygoscelis adeliae, colonies at Cape Royds, Cape Bird and Cape Crozier have changed over time, especially in relation to the Ross Sea region Marine Protected Area, MPA, established in 2017 and considering major environmental and biological factors that could have an effect on these populations. We will continue to collect new data annually to look at any affects the Ross Sea region MPA is having on these populations. Using data about population sizes of colonies and health of individuals from within the colonies, we will evaluate the overall health of the colonies and predict how we expect them to change in the near future. This is an important study as P. adeliae are an indicator species for their local ecosystem – the health of the penguin colonies reflects the health of the local ecosystem.
species composition of intertidal marine macroalgae in san francisco canaoay,...INFOGAIN PUBLICATION
The Philippines occupy the north of coral triangle, a huge area overlapping the Indian Ocean and the Pacific Ocean, and is famous for its extremely rich marine biodiversity. The taxonomical study of seaweeds started on the year 1750 and towards the end of the 20th century[1]. In Ilocos Sur, a comprehensive study on the marine benthic algae was made by Domingo in 1988.In this study, he reported 103 species, with 91 species reported for the first time for the province[2].As to this date, no taxonomical study made in San Francisco-Canaoay. This study used site description, Exhaustive Line Transect Method.The macroalgae recorded in San Francisco-Canaoay in the open area of the coastlines includeone genus&sevenspecies of Phaeophyta, one genus&one species of Chlorophyta, and one genus &nine species of Rhodophyta. The larger number of Rhodophyta can be attributed to the presence of abundant nutrients in the area and the luminosity of light of 35, 000 Lux value, which was favorable for the photosynthetic macroalgae.The specimens identified,58% were Phaeophyta, 34% were Chlorophyta, and 8% were Rhodophyta.There were more red algaes (Rhodophyta) in the open area due to the nature of these plant-like protists to thrive in running water with many nutrients. The number of brown algaes (phaeophyta) are not affected by the conditions of the water because of their toughness as compared to the aforementioned nature of red algaes[3].
Destruction and mitigation.. BY DR. ABHIJIT MITRAAbhijit Mitra
Dr. Abhijit Mitra, Associate Professor and former Head, Dept. of Marine Science, University of Calcutta (INDIA) has been active in the sphere of Oceanography since 1985. He obtained his Ph.D as NET qualified scholar in 1994. Since then he joined Calcutta Port Trust and WWF (World Wide Fund), in various capacities to carry out research programmes on environmental science, biodiversity conservation, climate change and carbon sequestration. Presently Dr. Mitra is serving as the advisor of Oceanography Division of Techno India University, Kolkata. He has to his credit about 388 scientific publications in various National and International journals, and 34 books of postgraduate standards. Dr. Mitra has successfully completed about 16 projects on biodiversity loss in fishery sector, coastal pollution, alternative livelihood, climate change and carbon sequestration. Dr. Mitra also visited as faculty member and invited speakers in several foreign Universities of Singapore, Kenya, Oman and USA. In 2008, Dr. Mitra was invited as visiting fellow at University of Massachusetts at Dartmouth, USA to deliver a series of lecture on Climate Change. Dr. Mitra also successfully guided 29 Ph.D students. Presently his domain of expertise includes environmental science, mangrove ecology, sustainable aquaculture, alternative livelihood, climate change and carbon sequestration.
Presentation during the 14th Association of African Universities (AAU) Conference and African Open Science Platform (AOSP)/Research Data Alliance (RDA) Workshop in Accra, Ghana, 7-8 June 2017.
Diversity and dispersion patterns of echinoderms in Babanlagan, Talisayan, Mi...Angelo Mark Walag
Echinoderms are fundamentally good indicators of health and status of coralline communities in marine waters. In this study, the diversity and distribution of echinoderm species were determined in Babanlagan, Talisayan, Misamis Oriental. In total, 387 individuals were collected coming from classes Echinoidea, Holothuroidea, Asteroidea, and Ophiuroidea. The majority of individuals collected were Protoreaster nodusus, which is a good indicator of reef health while the least abundant echinoderm species was Acanthaster planci. The pattern of distribution of majority of echinoderms was a clumped distribution while the other groups followed regular/uniform distribution, which may be due to limited dispersal ability and availability and available food sources. Moderate species diversity was also observed and species were rather similar in abundance, shown by the evenness index. This suggests good marine health, even under the threat of gleaning activities, active fishing, and habitat destruction. It is recommended that follow-up studies are conducted especially regarding monitoring of echinoderm species, to further assess the health of the intertidal zone in Babanlagan, Talisayan, Misamis Oriental.
ABSTRACT- Lizardfishes are commercially important group of species contributing to the fishery in the Indian EEZ. Information on predation, prey-predator relationship and their assessments in respect of Saurida tumbil and Saurida undosquamis have been derived in this study. A total number of 1630 specimens of S. tumbil and 926 of S. undosquamis were used for stomach content analysis. The specimens of S. tumbil examined in the study ranged between 13.0-53.0 cm (TL) and of S. undosquamis 13.0-41.0 cm. Qualitative and quantitative analysis revealed that the species S. tumbil prefers food in order of abundance as a teleost fishes (41%), molluscs (9.16%), shrimps (3.64%), crabs (1.41%) and squilla (0.37%) and S. undosquamis prefers teleost fishes (49%), molluscs (11%) and shrimps (3%). In S. tumbil, the highest feeding intensity observed in July (50%) and in S. undosquamis, in October (41%) and the lowest intensity recorded in the month of June for both the species. Monthly Gonado Somatic Index (GSI) shown that the highest feeding was observed in January (10.55%) and July (10.76%) for S. tumbil whereas, in case of S. undosquamis, the GSI was highest in August (16.58% for males and 17.80% for females). The pieces of sand granules, detritus and benthic organisms in the stomachs of the species indicating the benthic nature at the sea bottom in the search of food. Occurrence of juvenile lizardfishes in gut contents of both the species indicates that the lizardfishes are cannibalistic in nature.
Key-words- Lizardfish, feeding intensity, Gonado Somatic Index (GSI), Cannibalism
Confirmation records and new distribution of the red cornet fish fistularia p...MohammedWaled1
Confirmation records and new distribution of the
red cornet fish fistularia petimba lacepède, 1803
(actinopterygii: fistulariidae) in the Syrian Marine
Waters (Eastern Mediterranean)
Length-weight models and condition factors of fishes from Okpara Stream, Ouem...AI Publications
Length frequency distributions, length-weight models and condition factors of 21 dominant fish species of the Okpara stream (Oueme River) were examined in Northern-Benin in order to evaluate the well-being of these fish taxa. Samplings were made monthly from December 2015 to May 2017 with seines, gill nets hawks and a total of 9,302 individuals were collected. Fish abundance ranged from 53 individuals for Mormyrus rume to 2,818 for Hemichromis fasciatus. Standard length (SL) varied from 1.2 cm (Coptodon guineensis) to 51.8 cm (Chrysichthys nigrodigitatus). Length-weight regressions equations showed significant (p < 0.05) correlation coefficients (r) ranging between 0.4664 and 0.9949 with slopes (b) between 2.2262 and 3.7703 corresponding to isometric, positive allometric and negative allometric growths displayed by 4, 8 and 9 species, respectively. Condition factors K varied between 0.17 - 29.38 and species with higher well-being were Oreochromis niloticus with K=29.38, Hyperopisius bebe (K=20.14), Coptodon zillii (K=19.25), Mormyrus rume (K=17.13) and Sarotherodon galilaeus multifasciatus (K=16.16). A sustainable exploitation of these fishes requires an ecosystem restoration scheme including habitat protection, species conservation and an ecological follow-up of the Okpara stream.
First record of invasive croaking gourami, Trichopsis vittata (Cuvier 1831) ...Shoaibe H T Shefat
this study aimed to investigate the biology, source of introduction, impacts on native fish biodiversity and spreading pattern of this croaking gourami to develop proper conservation
strategy and implementation of a systematic approach.
Research Proposal - Are the Adélie penguin, Pygoscelis adeliae, populations w...ElizabethHowarth1
Rational - The focus on this study is to evaluate how the population size and health of Adélie penguin, Pygoscelis adeliae, colonies at Cape Royds, Cape Bird and Cape Crozier have changed over time, especially in relation to the Ross Sea region Marine Protected Area, MPA, established in 2017 and considering major environmental and biological factors that could have an effect on these populations. We will continue to collect new data annually to look at any affects the Ross Sea region MPA is having on these populations. Using data about population sizes of colonies and health of individuals from within the colonies, we will evaluate the overall health of the colonies and predict how we expect them to change in the near future. This is an important study as P. adeliae are an indicator species for their local ecosystem – the health of the penguin colonies reflects the health of the local ecosystem.
species composition of intertidal marine macroalgae in san francisco canaoay,...INFOGAIN PUBLICATION
The Philippines occupy the north of coral triangle, a huge area overlapping the Indian Ocean and the Pacific Ocean, and is famous for its extremely rich marine biodiversity. The taxonomical study of seaweeds started on the year 1750 and towards the end of the 20th century[1]. In Ilocos Sur, a comprehensive study on the marine benthic algae was made by Domingo in 1988.In this study, he reported 103 species, with 91 species reported for the first time for the province[2].As to this date, no taxonomical study made in San Francisco-Canaoay. This study used site description, Exhaustive Line Transect Method.The macroalgae recorded in San Francisco-Canaoay in the open area of the coastlines includeone genus&sevenspecies of Phaeophyta, one genus&one species of Chlorophyta, and one genus &nine species of Rhodophyta. The larger number of Rhodophyta can be attributed to the presence of abundant nutrients in the area and the luminosity of light of 35, 000 Lux value, which was favorable for the photosynthetic macroalgae.The specimens identified,58% were Phaeophyta, 34% were Chlorophyta, and 8% were Rhodophyta.There were more red algaes (Rhodophyta) in the open area due to the nature of these plant-like protists to thrive in running water with many nutrients. The number of brown algaes (phaeophyta) are not affected by the conditions of the water because of their toughness as compared to the aforementioned nature of red algaes[3].
Destruction and mitigation.. BY DR. ABHIJIT MITRAAbhijit Mitra
Dr. Abhijit Mitra, Associate Professor and former Head, Dept. of Marine Science, University of Calcutta (INDIA) has been active in the sphere of Oceanography since 1985. He obtained his Ph.D as NET qualified scholar in 1994. Since then he joined Calcutta Port Trust and WWF (World Wide Fund), in various capacities to carry out research programmes on environmental science, biodiversity conservation, climate change and carbon sequestration. Presently Dr. Mitra is serving as the advisor of Oceanography Division of Techno India University, Kolkata. He has to his credit about 388 scientific publications in various National and International journals, and 34 books of postgraduate standards. Dr. Mitra has successfully completed about 16 projects on biodiversity loss in fishery sector, coastal pollution, alternative livelihood, climate change and carbon sequestration. Dr. Mitra also visited as faculty member and invited speakers in several foreign Universities of Singapore, Kenya, Oman and USA. In 2008, Dr. Mitra was invited as visiting fellow at University of Massachusetts at Dartmouth, USA to deliver a series of lecture on Climate Change. Dr. Mitra also successfully guided 29 Ph.D students. Presently his domain of expertise includes environmental science, mangrove ecology, sustainable aquaculture, alternative livelihood, climate change and carbon sequestration.
Presentation during the 14th Association of African Universities (AAU) Conference and African Open Science Platform (AOSP)/Research Data Alliance (RDA) Workshop in Accra, Ghana, 7-8 June 2017.
Diversity and dispersion patterns of echinoderms in Babanlagan, Talisayan, Mi...Angelo Mark Walag
Echinoderms are fundamentally good indicators of health and status of coralline communities in marine waters. In this study, the diversity and distribution of echinoderm species were determined in Babanlagan, Talisayan, Misamis Oriental. In total, 387 individuals were collected coming from classes Echinoidea, Holothuroidea, Asteroidea, and Ophiuroidea. The majority of individuals collected were Protoreaster nodusus, which is a good indicator of reef health while the least abundant echinoderm species was Acanthaster planci. The pattern of distribution of majority of echinoderms was a clumped distribution while the other groups followed regular/uniform distribution, which may be due to limited dispersal ability and availability and available food sources. Moderate species diversity was also observed and species were rather similar in abundance, shown by the evenness index. This suggests good marine health, even under the threat of gleaning activities, active fishing, and habitat destruction. It is recommended that follow-up studies are conducted especially regarding monitoring of echinoderm species, to further assess the health of the intertidal zone in Babanlagan, Talisayan, Misamis Oriental.
ABSTRACT- Lizardfishes are commercially important group of species contributing to the fishery in the Indian EEZ. Information on predation, prey-predator relationship and their assessments in respect of Saurida tumbil and Saurida undosquamis have been derived in this study. A total number of 1630 specimens of S. tumbil and 926 of S. undosquamis were used for stomach content analysis. The specimens of S. tumbil examined in the study ranged between 13.0-53.0 cm (TL) and of S. undosquamis 13.0-41.0 cm. Qualitative and quantitative analysis revealed that the species S. tumbil prefers food in order of abundance as a teleost fishes (41%), molluscs (9.16%), shrimps (3.64%), crabs (1.41%) and squilla (0.37%) and S. undosquamis prefers teleost fishes (49%), molluscs (11%) and shrimps (3%). In S. tumbil, the highest feeding intensity observed in July (50%) and in S. undosquamis, in October (41%) and the lowest intensity recorded in the month of June for both the species. Monthly Gonado Somatic Index (GSI) shown that the highest feeding was observed in January (10.55%) and July (10.76%) for S. tumbil whereas, in case of S. undosquamis, the GSI was highest in August (16.58% for males and 17.80% for females). The pieces of sand granules, detritus and benthic organisms in the stomachs of the species indicating the benthic nature at the sea bottom in the search of food. Occurrence of juvenile lizardfishes in gut contents of both the species indicates that the lizardfishes are cannibalistic in nature.
Key-words- Lizardfish, feeding intensity, Gonado Somatic Index (GSI), Cannibalism
Food and Feeding Habits of Two Major Lizardfishes (Family: Synodontidae) ...
Similar to Aspects of life-history strategy of Marcusenius senegalensis (Pisces: Osteoglossiformes: Mormyridae; Steindachner, 1870) from Niger River in Northern Benin
Population structure, fecundity and morphological characteristics of M. vollenhovenii were studied around Lower Volta River, Ghana subject to dirt of information on this prawn species around the study location. The most prominent morphological characteristics already documented for identification of this species was rostrum bearing 13-15 continuous teeth dorsally and 4-5 teeth on its ventral part. These morphological traits formed the principal components for identification in this study. Results showed that morphological traits on second pereiopods such as presence of spines, spinules, teeth borne within the fingers, and dense projections of setae-like features on telson and uropod were observed relevant for identification purposes. Other results revealed that maximum total length recorded in this study (150-155mm) was higher than total length ranges (≤125mm) documented for this species in earlier studies. Consequently, two adult’s classes of prawns were identified (old adult class 81-120mm; and young adults 31-80mm) and older class was observed to be more in catches than the younger prawns. Absolute fecundity revealed that oocytes estimation varied with respect to seasons, ages of prawns and body sizes of specimens examined. In conclusion, this study observed that M. vollenhovenii fishery is operating in a sustainable manner at the time of this study around the study location.
Assessment of size structures, length-weight models and condition factors of ...AI Publications
The Eleotridae is one of the fish family widely distributed in the Benin coastal waters where the species constitute an important component of artisanal fisheries. The current study evaluates length frequency distributions, length-weight models and condition factors of Eleotrid fishes in order to assess their wellbeing in the degrading coastal waters of Benin. Fish samplings were made during eighteen (18) consecutive months and morphometric data were recorded and analyzed using SPSS computer software. Larger Eleotrids were Eleotris vittata, E. senegalensis, E. daganensis and Bostrychus africanus while Dormitator lebretonis, the most abundant species displayed small sizes (standard length) ranging between 1.2 - 11.30 cm. Overall, all the species showed unimodal size distributions except Eleotris daganensis that exhibited a bimodal size distribution in Lake Nokoué. Length-weight models showed allometric growth with slopes b ranging between 2.4725 and 3.7296 along with significant correlation coefficients (r) varying between 0.7695 and 0.9965. Condition factors (K) varied significantly across the four (4) coastal waters and ranged between 0.79 (Dormitator lebretonis) and 3.60 (Eleotris daganensis). The sustainable exploitation of Eleotrid fishes in the Benin coastal waters requires a holistic approach of ecosystem management including ecological follow-up, habitat restauration and species valorization.
Abstract
Grazing of livestock is the most widespread land-use practice in Northern part of Nigeria,
occupying about 60% of the land surface. These activities are usually carried out along
river channels and therefore, impact to a considerable extent on the riparian ecosystem.
This study assesses the effects of livestock grazing on riparian ecosystem along Gongola
River at Dadin Kowa, Yamaltu Deba LGA, Gombe State, Nigeria. Water samples and
laboratory test, field measurements and observation of vegetation species were employed
in the study. Descriptive and inferential statistics i.e. T-test was used to analyze the data.
The findings revealed that, shrubs are the dominant plant species with 23.17%, followed
by neem (Azadiractha indica) 18.30%, Herbs dominating 17.07%, and Mango (magnifera
indica) 13.41%. A t-test analysis reveals that there is significant difference in the height
and diameter of trees with t-value of 9.087. Plant species that are palatable to animals
have witnessed degradation through looping and trampling hence their survivals are at
risks. While the largest livestock composition are mainly cows constituting about
52.72%, followed by sheep 40%. Apart from polluting the water, the livestock routes and
riparian corridors are characterized by erosion thereby increasing to the
siltation/sedimentation of the Gongola River valley. Also, result of water quality analysis
revealed an uneven distribution in all the selected parameters. Mean pH value obtained
was 8.22, while calcium, magnesium, chloride, turbidity, Biochemical Oxygen Demand
were 10.88 mg/L, 0.23 mg/L, 21.26 mg/L, 564.00NTU and 11.29mg/L, respectively. This
implies that the water quality is not safe for human consumption and to a larger extent the
livestock. The study, therefore, recommends the need for creation of ranches in the area
by the Federal or State Government to preserve the natural environment from biodiversity
lost.
Analyses of Community Attributes of Meiofauna Under A Pollution Regime in the...Agriculture Journal IJOEAR
— Meiofauna community attributes of the lower Bonny estuary was investigated under a pollution regime. This is germane because of the strategic importance of meiofauna in the food chain and the sustenance of any aquatic ecosystem. Five stations representing diverse land based activities such as refuse dump site, fuel depot, fishing-landing areas, residential housing and a station located upstream (control) were chosen for investigation. The meiofauna samples were collected from sediments in three replicate spots per station per sampling months at low tide. Sediment samples were stirred through (63-212nm) meshes to separate meiofauna and organic debris. Meiofauna samples were processed by first washing Meiofauna through a sieve of fine mesh size made of silk material, in order to wash off formation and excess silt or mud. Meiofauna samples were sorted out and identified using standard keys. Result from field studies indicate that meiofauna population abundance and diversity varied slightly between stations and seasons. There was however, no established trend. Meiofauna were generally more abundant in the rainy season than in the dry season. In general, pollution indicator meiofaunal taxa were more in all stations except the control station; the increasing impact of pollutants in the river led to a rise in the relative abundance of r-strategist genera like Chromadora. We conclude that the application of meiofaunal indices can be a useful tool for assessing the environmental quality of estuarine ecosystems.
Diversity and abundance of terrestrial mammals in the northern periphery of ...Innspub Net
The Tanoé-Ehy Marsh Forest (TEMF), an unprotected forest that is about to be turn into a voluntary nature reserve is a forest block in south-eastern Côte d’Ivoire known as being of great importance for the conservation of biodiversity. But in the rainy season, that forest is largely over flooded and terrestrial mammals are likely to move to the periphery and make them vulnerable to anthropogenic threats. Our objectives are to determine the diversity, the relative abundance of terrestrial mammals and their spatial distribution in the northern periphery of the TEMF during the rainy season. We collected data by conducting recce surveys after interviews with local people. In total, we obtained 33 species among which ten primates’ species were identified. According to the recce survey, the African Civet (Civettictis civetta) and the Bushbuck (Tragelaphus scriptus) are the most common and abundant species in the study area with 12.7% and 12.0% of relative abundance respectively. In addition, six of the listed species are on the IUCN Red List, including Piliocolobus waldronae, a critically endangered species, Cercocebus lunulatus and Cercopithecus roloway endangered species, Colobus vellerosus, Phataginus tetradactyla and Phataginus tricuspis, three vulnerable species. Thus, the consideration of the periphery for the sustainable management of the TEMF is proving to be an imperative.
The amphibian’s fauna of a West African forest relict near a hydroelectric Da...Innspub Net
This study reports the amphibian’s fauna sampled from the Biodiversity Conservation Area of the hydroelectric dam of Soubré city (southwestern Côte d’Ivoire). This study aims to provide a better understanding of the diversity of amphibians in this relict forest of 200 ha, in order to assess the ecological health of this ecosystem for conservation and sustainable management perspectives. During dry season (from 26 February to 4 March 2018) and rainy season (from 17 to 23 June 2018), we recorded 14 species of anurans grouped into eight genera and six families. The study sites comprise an amphibian fauna consisting mainly of savannah specialists and degraded forest (64.28% of total species richness). Based on the IUCN Red List, all species recorded are of least concern. Also, these species are well distributed in the different regions of Côte d’Ivoire and Africa. Thus, it is necessary to monitor the ecology of the species and to protect subsequently the different habitats of this area.
3 ijfaf jul-2017-1-evaluation of the ichthyofaunalAI Publications
Fish constitute more than half of the total number of all the aquatic vertebrates in the world; thus, a study was carried out for six months from January-June, 2016 to investigate the physico-chemical parameters, composition, abundance and diversity of ichthyofauna present in some sections of Omambala, Ezu and Ahommiri Rivers in Anambra state, Nigeria. Water samples were collected for physico-chemical analysis and fish samples were also collected with the assistance of artisanal fishermen using different types of traditional fishing gears namely - gill nets, cast nets, hook and line, local traps (baited) and bag nets to evaluate fish species composition and abundance. The result of the physico-chemical analysis showed uniform values for temperature (25±0.16oC-30±0.48oC), dissolved oxygen (3.65±0.78-5.65±0.11mg/l) and biochemical oxygen demand (13±0.03-16±0.08mg/l) which favoured the distribution of fishes present in different sections of the three Rivers. A total catch of 11,031 fishes were recorded from the three Rivers which comprised 11 orders, 29 families, 43 genera and 69 species. Umuoba-Anam section had 9691 catches, Ebenebe section (702) and Awa section (638). Monthly composition showed highest in March (1,909) and June (2,294) for dry and rainy seasons respectively. Seasonal composition showed highest during the rainy season with a total number of 5922 fishes while 5109 fishes was recorded for the dry season. The diversity indices of the three Rivers indicated diverse communities with ten common species variety and Shannon Weiner (H’) diversity index of 2.755-3.682. Tilapia zilli (22.2%) was the most common and abundant species followed by Clarias anguillaris (21.4%), Malapterus electricus (18.9%), Heterobranchus bidorsalis (15.4%), Xenomystis nigri (14.6%), Heterotis niloticus (13.0%), Auchenoglanis monkei (11.0%), Tilapia dageti (10.2%), Hepsetus odoe (8.1%) and Bagrus filamentosus (7.2%). The study revealed that taxa richness and species diversity increase with increased water level and uniform physico-chemical changes. Further survey of fish species diversity and abundance should be carried out continuously for a longer period on a larger scale for a thorough assessment of the water bodies and their fishery potentials.
Diversity and abundance of Macrobenthos in a subtropical estuary, BangladeshAbdullaAlAsif1
Soft bottom macrobenthos are important component of the marine and coastal trophic chain. There has been sparse information regarding the distribution of soft bottom macrobenthos form the coastal water of Bangladesh. Consequently, the present study was an effort to reveal the diversity and abundance of macrobenthos in the Feni Estuary in a seasonal pattern together with the hydrological factors. A total of 17 taxa families of soft-bottom invertebrates were found over the two sampling seasons. The current study yielded a total number of 34,726 ind./m 2 (mean 2480ind./m 2) including 18,909ind./m 2 in wet season (mean 2682ind./m 2) and 15,817 ind./m 2 in dry season (2259ind./m 2). The highest density of soft-bottom invertebrates was in the wet season while the lowest number in the dry season. A total of 5 groups of macrobenthos were found over the two sampling seasons. The dominant group was Polychaeta that contributed 43.60% of the total soft-bottom invertebrates. The values of biodiversity indices were higher in dry season compare to the wet season in most of the sampling station during the study period.
Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems w...Premier Publishers
Aquatic macrophytes hold several niches within the ecosystem, including inter alia water purification, carbon sequestration and serve as microhabitats for aquatic insects. These dynamic roles make macrophytes good indicators of current environmental conditions. Hence assessing their abundance in line with wetland ecosystem dynamics and function is essential. Frequency of occurrence and density values were estimated, using twenty (20) 2 m x 2 m quadrats for each macrophyte encountered. The results of the study revealed twenty-one (21) macrophytes belonging to 16 families. These ponds varied markedly in terms of species composition and in numerical strength such that Polygonum lanigerum (1143+175st/ha), Setaria verticillata (337.5+ 32.8st/ha), Azolla pinnata (337.7+ 16.4 st/ha) recorded high density values while Lagenaria breviflora (18.7±2.19), Sida acuta (18.75±5.30), Ludwigia erecta (18.7±0.15) and Milletia aboensis (18.7±0.03) were the least abundant species. Pond A and D with 11 taxa each had the higher Shannon-Wiener (2.192, 2.214) and Simpson (0.8699, 0.8787) diversity indices respectively when compared to the other ponds. On the contrary, pond C with four taxa had the least Shannon-Wiener and Simpson diversity indices (1.253, 0.6782) respectively. Equitability and evenness ranged between 0.914 - 0. 952 and 0.814 - 0.900 respectively. Bray and Curtis cluster analysis showed that pond B was the most dissimilar compared to other ponds in terms of the taxa composition.
Sea cows in the Sahel : research and conservation on the African Manatee in t...Sahara Conservation Fund
Presented during the 17h Annual Sahelo-Saharan Interest Group Meeting organized by the NGO Sahara Conservation Fund in Senegal, from 4 to 6 May 2017. The Sahara Conservation Fund (SCF) gathers every year about a hundred people who are interested in the field of Sahelo-Saharan species conservation.
Population dynamics of 15 fish species in Grand-Lahou lagoon (West Africa, Cô...Open Access Research Paper
This study described growth, mortality, recruitment patterns and exploitation rates of 15 fish species in Grand-Lahou lagoon (Côte d’Ivoire). Monthly length-frequency data collected from artisanal fisheries from November 2013 to October 2014 were analyzed with FiSAT software using the ELEFAN package to estimate the population parameters of fishes. Asymptotic values for total length (L∞) ranged from 15.75 cm for Synodontis schall to 59.80 cm for Trachinotus teraia. Growth rate (k) varied from 0.19 for Coptodon guineensis to 0.98 for Caranx hippos. The growth performance index estimates were close to the values found by other authors for most of the fish species. The total mortality (Z) high values were recorded for Synodontis schall (Z= 4.15 year-1; M = 2.50 year-1) Schilbe mandibularis (Z= 2.19 year-1; M=1.33 year-1). Fishing mortality (F) and exploitation rate (E) were found to be less than the optimum levels of exploitation for most fish species. The exploitation rate (E) was higher than the maximum sustainable yield (Emax) for Caranx hippos and higher than E0.5 for Eucinostomus melanopterus, Elops lacerta and Synodontis schall. Recruitment was noted as year-round and bimodal for most studied populations. These results demonstrate that some fish stocks necessitate effective management measures particularly C. hippos, E. melanopterus, E. lacerta and S. schall.
Analysis of the rate of change of mangrove forest ecosystem in calabar south,...Alexander Decker
International peer-reviewed academic journals call for papers, http://www.iiste.org/Journals
Similar to Aspects of life-history strategy of Marcusenius senegalensis (Pisces: Osteoglossiformes: Mormyridae; Steindachner, 1870) from Niger River in Northern Benin (20)
The Statutory Interpretation of Renewable Energy Based on Syllogism of Britis...AI Publications
The current production for energy consumption generates harmful impacts of carbon dioxide to the environment causing instability to sustainable development goals. The constitutional reforms of British Government serve to be an important means of resolving any encountered incompatibilities to political environment. This study aims to evaluate green economy using developed equation for renewable energy towards political polarization of corporate governance. The Kano Model Assessment is used to measure the equivalency of 1970 Patents Act to UK Intellectual Property tabulating the criteria for the fulfillment of sustainable development goals in respect to the environment, artificial intelligence, and dynamic dichotomy of administrative agencies and presidential restriction, as statutory interpretation development to renewable energy. The constitutional forms of British government satisfy the sustainable development goals needed to fight climate change, advocate healthy ecosystem, promote leadership of magnates, and delegate responsibilities towards green economy. The presidential partisanship must be observed to delineate parties of concerns and execute the government prescriptions in equivalence to the dichotomous relationship of technology and the environment in fulfilling the rights and privileges of all citizens. Hence, the political elites can execute corporate governance towards sustainable development of renewable energy promoting environmental parks and zero emission target of carbon dioxide discharges. The economic theory developed in statutory interpretation for renewable energy serves as a tool to reduce detrimental impacts of carbon dioxide to the environment, mitigate climate change, and produce artefacts of bioenergy and artificial intelligence promoting sustainable development. It is suggested to explore other vulnerabilities of artificial intelligence to prosper economic success.
Enhancement of Aqueous Solubility of Piroxicam Using Solvent Deposition SystemAI Publications
Piroxicam is a non-steroidal anti-inflammatory drug that is characterized by low solubility-high permeability. The present study was designed to improve the dissolution rate of piroxicam at the physiological pH's through its increased solubility by using solvent deposition system.
Analysis of Value Chain of Cow Milk: The Case of Itang Special Woreda, Gambel...AI Publications
Ethiopia has a long and rich history of dairy farming, which was mostly carried out by small and marginal farmers who raised cattle, camels, goats, and sheep, among other species, for milk. Finding the Itang Special Woreda cow milk value chain is the study's main goal. In order to gather primary data, 204 smallholder dairy farmer households were randomly selected, and the market concentration ratio was calculated using 20 traders. Descriptive statistics, econometric models, and rank analysis were used to achieve the above specified goals. Out of all the participants in the milk value chain, producers, cafés, hotels, and dairy cooperatives had the largest gross marketing margins, accounting for 100% of the consumer price in channels I and II, 55% in channels III and V, and 25.5% in channels V. The number of children under five, the number of milking cows owned, the amount of money from non-dairy sources, the frequency of extension service contacts, the amount of milk produced each day, and the availability of market information were found to have an impact on smallholders' involvement in the milk market. Numerous obstacles also limited the amount of milk produced and marketed. The poll claims that general health issues, sickness, predators, and a lack of veterinary care are plaguing farmers. In order to address the issue of milk perishability, the researchers recommended the host community and organization to construct an agro milk processor, renovate the dairy cooperative in the study region, and restructure the current conventional marketing to lower the transaction and cost of milk marketing.
Minds and Machines: Impact of Emotional Intelligence on Investment Decisions ...AI Publications
In the evolving landscape of financial decision-making, this study delves into the intricate relationships among Emotional Intelligence (EI), Artificial Intelligence (AI), and Investment Decisions (ID). By scrutinizing the direct influence of human emotional intelligence on investment choices and elucidating the mediating role of AI in this process, our research seeks to unravel the complex interplay between minds and machines. Through empirical analysis, we reveal that EI not only directly impacts ID but also exerts its influence indirectly through AI-mediated pathways. The findings underscore the pivotal role of emotional awareness in investor decision-making, augmented by the technological capabilities of AI. It suggests that most investors are influenced by the identified emotional intelligence when making investment decisions. Furthermore, AI substantially impacts investors' decision-making process when it comes to investing; nevertheless, AI partially mediates the relationship between emotional intelligence and investment decisions. This nuanced understanding provides valuable insights for financial practitioners, policymakers, and researchers, emphasizing the need for holistic strategies that integrate emotional and technological dimensions in navigating the intricacies of modern investment landscapes. As the synergy between human intuition and artificial intelligence becomes increasingly integral to financial decision-making, this study contributes to the ongoing discourse on the symbiotic relationship between minds and machines in investments.0
Bronchopulmonary cancers are common cancers with a poor prognosis. It is the leading cause of death by cancer in Algeria and in the world. Behind this unfavorable prognosis hides numerous disparities according to age, sex, and exposure to risk factors, ranking 4th among incident cancers and developing countries including Algeria, all sexes combined. It ranks 2nd cancers in men and 3rd among women. Whatever the age observed, the incidence of this cancer is higher in men than in women, however the gap is narrowing to the detriment of the latter. The results of scientific research agree to relate trends in incidence and mortality rates to tobacco consumption, including passive smoking. Furthermore, other risk factors are mentioned such as exposure to asbestos in the workplace or to radon for the general population, or even genetic predisposition. However, the weight of these etiological and/or predisposing factors is in no way comparable to that of tobacco in the genesis of lung cancer and the resulting mortality. We provide a literature review in our article on the descriptive and analytical epidemiology of lung cancer.
Further analysis on Organic agriculture and organic farming in case of Thaila...AI Publications
The objective of this paper is to present Further analysis on Organic agriculture and organic farming in case of Thailand agriculture and enhancing farmer productivity. In view of the demand for organic fertilizers, efforts should also be made to enhance and to develop more effective of compost, bio-fertilizer, and bio-pesticides currently used by farmers. Likewise, emphasis should also be laid on the cultivation of legumes and other crops that can enhance the fertility of the soil, as practiced by farmers in many developing countries to fertilize their lands. On the other hand, most of the farmers who practice this farm system found that they are adopting a number of SLMs and interested in joining the meeting or training to gain more and more knowledge.
Current Changes in the Role of Agriculture and Agri-Farming Structures in Tha...AI Publications
The objective os this study is to present Current Changes in the Role of Agriculture and Agri-Farming Structures in Thailand and Vietnam with SLM practices. Farmer’s adoption and investment in SLM is a key for controlling land degradation, enhancing the well-being of society, and ensuring the optimal use of land resources for the benefit of present and future generations (World Bank, 2006; FAO, 2018). And agriculture remains an essential element of lives of many farmers in term of the strong cultural and symbolic values that attach current working generation to do and to spend time for it but not intern of income generating.
Growth, Yield and Economic Advantage of Onion (Allium cepa L.) Varieties in R...AI Publications
Haphazard and low soil fertility, low yielding verities and poor agronomic practices are among the major factors constraining onion production in the central rift valley of Ethiopia. Therefore, a field experiment was conducted in East Showa Zone of Adami Tulu Jido Combolcha district in central rift valley areas at ziway from October 2021 to April 2022 to identify appropriate rate of NPSB fertilizer and planting pattern of onion varieties. The experiment was laid out in split plot design of factorial arrangement in three replications. The main effect of NPSB blended fertilizer rates and varieties (red coach and red king) significantly (p<0.01) influenced plant height, leaf length, leaf diameter, leaf number and fresh leaf weight, shoot dry matter per plant, and harvest index. Total dry biomass, bulb diameter, neck diameter, average fresh bulb weight, bulb dry matter, marketable bulb yield, and total bulb yield were significantly (p<0.01) influenced only by the main effect of NPSB blended fertilizer rates. In addition, unmarketable bulb yield was statistically significantly affected (p≥0.05) by the blended fertilizer rates and planting pattern. Moreover, days to 90% maturity of onion was affected by the main factor of NPSB fertilizer rate, variety and planting pattern. The non-fertilized plants in the control treatment were inferior in all parameters except unmarketable bulb yield and harvest index. Significantly higher marketable bulb yield (41 t ha-1) and total bulb yield (41.33 t ha-1) was recorded from 300 kg ha-1 NPSB blended fertilizer rate applied. Double row planting method and hybrid red coach onion variety had also gave higher growth and yields. The study revealed that the highest net benefit of Birr, 878,894 with lest cost of Birr 148,006 by the combinations of 150 kg blended NPSB ha-1 with double row planting method (40cm*20cm*7cm) and red coach variety which can be recommendable for higher marketable bulb yield and economic return of hybrid onion for small scale farmers in the study area. Also, for resource full producers (investors), highest net benefit of Birr 1,205,372 with higher cost (159,628 Birr) by application of 300 kg NPSB ha-1 is recommended as a second option. However, the research should be replicated both in season and areas to more verify the recommendations.
Evaluation of In-vitro neuroprotective effect of Ethanolic extract of Canariu...AI Publications
The ethanolic extract of canarium solomonense leaves (ecsl) was studied for its neuroprotective activity. The neuroprotective activity of ECSL was found to have a significant impact on neuronal cell death triggered by hydrogen peroxide (MTT assay) in human SH-SY5Y neuroblastoma cells. Scopolamine, a muscarinic receptor blocker, is frequently used to induce cognitive impairment in laboratory animals. Injections of scopolamine influence multiple cognitive functions, including motor function, short-term memory, and attention. Using the Morris water maze, the Y maze, and the passive avoidance paradigm, memory enhancing activity in scopolamine-induced amnesic rats was evaluated. Using the Morris water maze, the Y maze, and the passive avoidance paradigm, ECSL was found to have a substantial effect on the memory of scopolamine- induced amnesic rats. Our experimental data indicated that ECSL can reverse scopolamine induced amnesia and assist with memory issues.
The goal of neuroprotection is to shield neurons against damage, whether that damage is caused by environmental factors, pathogens, or neurodegenerative illnesses. Inhibiting protein-based deposit buildup, oxidative stress, and neuroinflammation, as well as rectifying abnormalities of neurotransmitters like dopamine and acetylcholine, are some of the ways in which medicinal herbs have neuroprotective effects [1-3]. This review will focus on the ways in which medicinal herbs may protect neurons.
A phytochemical and pharmacological review on canarium solomonenseAI Publications
The genus Canarium L. consists of 75 species of aromatic trees which are found in the rainforests of tropical Asia, Africa and the Pacific. The medicinal uses, botany, chemical constituents and pharmacological activities are now reviewed. Various compounds are tabulated according to their classes their structures are given. Traditionally canarium solomonense have been used to treat a broad array of illnesses. Pharmacological actions for canarium solomonense as discussed in this review include antibacterial, antimicrobial, antioxidant, anti-inflammatory, hepatoprotective and antitumor activity.
Influences of Digital Marketing in the Buying Decisions of College Students i...AI Publications
This research investigates the influence of digital marketing channels on purchasing decisions among college students in Ramanathapuram District. The study highlights that social media marketing, online advertising, and mobile marketing exhibit substantial positive effects on purchase decisions. However, email marketing's impact appears to be more complex. Moreover, the study explores how demographic variables like gender and academic level shape these effects. Notably, freshman students display varying susceptibility to specific digital marketing messages compared to their junior, senior, or graduate counterparts. These findings offer crucial insights for marketers aiming to tailor their strategies effectively to the preferences and behaviors of college students. By understanding the differential impacts of various digital marketing channels and considering demographic nuances, marketers can refine their approaches, optimize engagement, and ultimately enhance the effectiveness of their campaigns in targeting this demographic.
A Study on Performance of the Karnataka State Cooperative Agriculture & Rural...AI Publications
The Karnataka State Co-operative Agriculture and Rural Development Bank Limited is the apex bank of all the primary co-operative agriculture and rural development banks in the state. All the PCARD Banks in the state are affiliated to it. The KSCARD Bank provides financial accommodation to the PCARD Banks for their lending operations. In order to quick sanction and disbursement of loans and supervision over the PCARD Banks the KSCARD Bank has opened district level branches. Bank has established Women Development Cell to promote entrepreneurship among women in 2005. The Bank is identifying women borrowers in the rural areas by assigning suitable projects to motivate their self-confidence to lead independent life. Progress made in financing women entrepreneurs women.
Breast hamartoma is a rare, well-circumscribed, benign lesion made up of a variable quantity of glandular, adipose and fibrous tissue. This is a lesion that can affect women at any age from puberty. With the increasingly frequent use of imaging methods such as mammography and ultrasound as well as breast biopsy, cases of hamartoma diagnosed are increasing. The diagnosis of these lesions is made by mammography. The histological and radiological aspects are variable and depend on its adipose tissue content. The identification of these lesions is important in order to avoid surgical excisions. We report radio-clinical and pathological records of breast hamartoma.
A retrospective study on ovarian cancer with a median follow-up of 36 months ...AI Publications
Ovarian cancer is relatively common but serious and has a poor prognosis. The aim of this study is to highlight the epidemiological, diagnostic, therapeutic and evolutionary aspects of this malignant pathology managed at the Bejaia university hospital center. This is a retrospective and descriptive study over a period of 3 years (2019 - 2022) carried out on 20 patients who developed ovarian cancer. The average age of the patients was 50 years old, 53.23% of whom were over 45 years old. The CA-125 blood test was positive in 18 out of 20 patients. The tumors were discovered on ultrasound in 87.10% of cases and at laparotomy in 12.90%. Total hysterectomy with bilateral adnexectomy was the most performed procedure (64.52%). The early postoperative course was simple. 15 patients underwent second look surgery (16.13%) for locoregional recurrences. Epithelial tumors were the most frequent histological type (93.55%), including 79% in the advanced stage ( IIIc -IV) and 21% in the early stage (Ia- Ib ). Adjuvant chemotherapy was administered in 80% of patients. With a median follow-up of 36 months, 2 patients were lost to follow-up. The evolution was favorable in 27.42% and in 25.81% deaths occurred late postoperatively. Ovarian cancer is not common but serious given the advanced stages and the high rate of late postoperative deaths which were largely observed in patients deprived of adequate neoadjuvant or adjuvant chemotherapy.
More analysis on environment protection and sustainable agriculture - A case ...AI Publications
This study presents a case of tea and coffee crops , esp. environment protection and sustainable agriculture in Son La and Thai Nguyen of Vietnam. Research results show us that The process of having an agricultural product goes through many steps such as planting, planning, harvesting, packing, transporting, storing and distributing. - The State adopts policies to encourage innovation of agricultural production models and methods towards sustainability, adapting to climate change, saving water, and limiting the use of inorganic fertilizers and pesticides. chemicals and products for environmental treatment in agriculture; develop environmentally friendly agricultural models. Our research limitation is that we can expand for other crops, industries and markets as well.
Assessment of Growth and Yield Performance of Twelve Different Rice Varieties...AI Publications
The present investigation entitled “Assessment of growth and yield performance of twelve different rice varieties under north Konkan coastal zone of Maharashtra” was carried out during the kharif season of the year 2021 and 2022 on the field of ASPEE, Agricultural Research and Development Foundation, Tansa Farm, At Nare, Taluka Wada, District Palghar, Maharashtra, India. The experiment was laid out in Randomized Block Design (RBD). The twelve varieties namely Zini, Jaya, Dandi, Rahghudya, Govindbhog, Dangi, Gurjari, VNR-7, VNR-8, VNR-9, Karjat-3, and Karjat-5 were replicated thrice. The plant height (cm), number of tillers per plant, number of panicles per plant, number of panicles (m²), and length of panicle (cm) were noted to the maximum with cv. “VNR-7”. The highest number of seeds per panicle, test weight (gm), grain yield (q/ha), and straw yield (q/ha) were recorded with the cv. “VNR-7”. While the lowest number of days to 50% flowering was also recorded with cv. “VNR-7” during the year 2021 and 2022.
Cultivating Proactive Cybersecurity Culture among IT Professional to Combat E...AI Publications
In the current digital landscape, cybercriminals continually evolve their techniques to execute successful attacks on businesses, thus posing a great challenge to information technology (IT) professionals. While traditional cybersecurity approaches like layered defense and reactive security have helped IT professionals cope with traditional threats, they are ineffective in dealing with evolving cyberattacks. This paper focuses on the need for a proactive cybersecurity culture among IT professionals to enable them combat evolving threats. The paper emphasis that building a proactive security approach and culture can help among IT professionals anticipate, identify, and mitigate latent threats prior to them exploiting existing vulnerabilities. This paper also points out that as IT professionals use reactive security when dealing with traditional attacks, they can use it collaboratively with proactive security to effectively protect their networks, data, and systems and avoid heavy costs of dealing with cyberattack’s aftermaths and business recovery.
The Impacts of Viral Hepatitis on Liver Enzymes and BilrubinAI Publications
Viral hepatitis is an infection that causes liver inflammation and damage. Several different viruses cause hepatitis, including hepatitis A, B, C, D, and E. The hepatitis A and E viruses typically cause acute infections. The hepatitis B, C, and D viruses can cause acute and chronic infections. Hepatitis A causes only acute infection and typically gets better without treatment after a few weeks. The hepatitis A virus spreads through contact with an infected person’s stool. Protection by getting the hepatitis A vaccine. Hepatitis E is typically an acute infection that gets better without treatment after several weeks. Some types of hepatitis E virus are spread by drinking water contaminated by an infected person’s stool. Other types are spread by eating undercooked pork or wild game. Hepatitis B can cause acute or chronic infection. Recommendation for screening for hepatitis B in pregnant women or in those with a high chance of being infected. Protection from hepatitis B by getting the hepatitis B vaccine. Hepatitis C can cause acute or chronic infection. Doctors usually recommend one-time screening of all adults ages 18 to 79 for hepatitis C. Early diagnosis and treatment can prevent liver damage. The hepatitis D virus is unusual because it can only infect those who have a hepatitis B virus infection. A coinfection occurs when both hepatitis D and hepatitis B infections at the same time. A superinfection occurs already have chronic hepatitis B and then become infected with hepatitis D. The aim of this study is to find the effect of each type of viral hepatitis on the bilirubin (TB , DSB) , and liver enzymes; AST, ALT, ALP,GGT among viral hepatitis patients. 200 patients were selected from the viral hepatitis units in the central public health laboratory in Baghdad city, all the chosen cases were confirmed as a positive samples , they are classified into four equal group each with fifty individual and with a single serological viral hepatitis type either; anti-HAV( IgM ) , HBs Ag , anti-HCV ,or anti-HEV(IgM ). All patients were tested for; serum bilirubin ( TB ,D.SB ) , AST , ALT , ALP , GGT. Another fifty quite healthy and normal person was selected as a control group for comparison. . Liver enzymes and bilirubin changes are more pronounced in HAV, HEV than HCV and HBVAST and ALT lack some sensitivity in detecting HCV ,HBV and mild elevations of ALT or AST in asymptomatic patients can be evaluated efficiently by considering ,hepatitis B, hepatitis C. ALT is generally a more sensitive indicator of acute liver cell damage than AST, It is relatively specific for hepatocyte necrosis with a marked elevations in viral hepatitis. Liver enzymes and bilirubin changes are more pronounced in HAV, HEV than HCV and HBV.AST and ALT lack some sensitivity in detecting HCV ,HBV and mild elevations of ALT or AST in asymptomatic patients can be evaluated efficiently by considering ,hepatitis B, hepatitis C. ALT is generally a more sensitive indicator of acute liver
Determinants of Women Empowerment in Bishoftu Town; Oromia Regional State of ...AI Publications
The purpose of this study was to determine the status of women's empowerment and its determinants using women's asset endowment and decision-making potential as indicators. To determine representative sample size, this study used a two-stage sampling technique, and 122 sample respondents were selected at random. To analyze the data in this study, descriptive statistics and a probit model were used. The average women's empowerment index was 0.41, indicating a relatively lower status of women's empowerment in the study area. According to the study's findings, only 40.9% of women were empowered, while the remaining 59.1% were not. The probit model results show that women's access to the media, women's income, and their husbands' education status have a significant and positive impact on the status of women's empowerment, while the family size of households has a negative impact. As a result, it is important to enhance women's access to the media and income, promote family planning and contraception, and improve men's educational status in order to improve the status of women's empowerment.
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Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Multi-source connectivity as the driver of solar wind variability in the heli...
Aspects of life-history strategy of Marcusenius senegalensis (Pisces: Osteoglossiformes: Mormyridae; Steindachner, 1870) from Niger River in Northern Benin
1. International Journal of Forest, Animal and Fisheries Research (IJFAF)
[Vol-4, Issue-1, Jan-Feb, 2020]
ISSN: 2456-8791
https://dx.doi.org/10.22161/ijfaf.4.1.1
www.aipublications.com/ijfaf Page | 1
Open Access
Aspects of life-history strategy of Marcusenius
senegalensis (Pisces: Osteoglossiformes:
Mormyridae; Steindachner, 1870) from Niger
River in Northern Benin
Kayode Nambil Adjibade1
, Alphonse Adite1*
, Hamidou Arame1
, Antoine
Chikou2
and Youssouf Abou1
1
Laboratoire d’Ecologie et de Management des Ecosystèmes Aquatiques (LEMEA), Département de Zoologie, Faculté des Sciences et
Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin.
2
Laboratoire d’Hydrobiologie et d’Aquaculture, Faculté des Sciences Agronomiques, Université d’Abomey-Calavi, 01 BP 526 Cotonou,
Benin.
Corresponding author
Abstract—Marcusenius senegalensis (Steindachner, 1870) is the dominant mormyrid in Niger River in
Northern-Benin where this fish species constitutes an important component of artisanal fisheries. The current
study documented the reproductive biology of M. senegalensis in order to contribute to management and
sustainable exploitation. Monthly samplings were conducted between February 2015 and July 2016 using
gillnets, cast net, and seine. Males dominated the population with a sex ratio of 1:0.96 in favor of males. Sizes at
first sexual maturity were 167.89 mm-TL for males and 163.81 mm-TL for females. Monthly gonadosomatic
index (GSI) averaged 0.12 ± 0.09 for males and 1.32 ± 1.56 for female and peaks recorded indicated that
spawning occured from June to September. Fecundity were moderate to low (844 – 12,643 eggs) and
significantly (p < 0.05) increased with total length and body weight. Thespecies showed egg diameters varying
between 0.21 and to 1.77 mm and ovaries comprised oocytes at all stages of maturation indicating that M.
senegalensis displayed a multi-spawning behavior. Marcuseniussenegalensis exhibited a demographic strategy
between r and K, yet more inclined towards K-selected strategy. In Niger River, reproduction grounds were
being severely degraded affecting recruitment and stocks. The current findings are valuable data to design a
species management scheme that should includes spawning ground protection, species conservation and
valorization and fisheries/aquaculture development.
Keywords— K-selected, management, Marcusenius senegalensis, multi-spawning, reproduction grounds.
I. INTRODUCTION
The African bulldog fish, Marcusenius
senegalensis (Steindachner, 1870) is the most common
and widespread mormyrid species inhabiting African
riverine and even lacustrine habitats where they constitute
an important commercial component of the freshwater
fisheries (Scheffel and Kramer, 1997). In particular, M.
senegalensis is one of the top mormyrid occurring in most
running waters from the African Western Region
(Adjibade et al., 2019a). Taxonomically, the African
bulldog fish belongs to Osteichthyes class, Actinopterygii
sub-class, Osteoglossiformes order, Mormyridae family,
Marcusenius genus and Marcusenius senegalensis species
(Moyle and Cech 2004, ).
The genus Marcusenius, the largest among
mormyrids, comprised about 40 valid species that form a
polyphyletic group (Boden et al., 1997). Marcusenius
may be recognized by its moderately elongated body,
grew silvery, a chin well developed, fleshy with globular
swelling, a snout poorly developed and shorter than
postorbital length, a fleshy submental swelling, a lower
jaw slightly longer than upper, nostrils situated at about
2. International Journal of Forest, Animal and Fisheries Research (IJFAF)
[Vol-4, Issue-1, Jan-Feb, 2020]
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mid-distance between eye and snout tip, a caudal
peduncle depth 2-5 times in its length, a dorsal fin with
19-36 rays, an anal fin with 25-43 rays, a pectoral fin with
10-12 rays, a pelvic fin with 6 rays, a distance between
pectoral and pelvic fins shorter than distance between
pelvic and anal fins, a caudal fin with 36-46 rays, 38-98
lateral line scales, 12-28 transversal line scales, 7-21
transversal line scales between dorsal and anal fins, 8-18
caudal peduncle scales, and 3-10 conical or bicuspid oral
jaw teeth (Boden et al., 1997). The maximal standard
length (SL) observed for this species was 321 mm and the
maximal total weight was 200g (Bigorne, 2003).
Marcusenius senegalensis, like other mormyrids,
possesses an electric organ located in the caudal peduncle
that generates a discharge that is species-specific and is
used for communication, orientation and object location
(Hopkins, 1981). The species is a nocturnal, benthic, egg-
scattering pelagic spawners (Paugy, 2002). With regards
to feeding habit,M. senegalensis is an invertivore
consuming mainly aquatic insects, detritus, sand particles,
crustaceans, mollusks and phytoplankton (Adjibade et al.,
2019b).
In Benin running waters, mormyrids are well-
distributed from Northern to Southern regions and appear
to be a commercially and economically valuable
component of the inland water fisheries. As reported by
the Benin Fisheries Department(Direction des Pêches,
1990) and Adjibade etal. (2019a), annual catches of
mormyrids in Benin reached 248 tons. In Niger River in
Benin, Koba (2005)reported that mormyrids were one of
the most valuable fishes and numerically accounted for
12.65% of the fish assemblages. Also, a recent fisheries
survey by Adjibade et al. (2019a) in Niger River in Benin
revealed that M. senegalensis dominated Mormyrid
assemblages and numerically made 43.74% of the
Mormyridae fish community.Despite its great importance
in artisanal fisheries in Niger River that currently
undergoes severe habitat degradations, almost nothing is
known about the life history strategy of M. senegalensis
in this regional running water in Benin (Nwani et al.,
2006). Knowledge of reproductive ecology is crucial to
evaluate maturation, spawning, recruitment, and
reproduction ground status in order to conserve and
protect the species and to assure its permanent
establishment.
The current study documents the life history
strategy and the reproductive ecology of M. senegalensis
in Niger River in Benin in order to provide valuable data
for species conservation and management.
II. MATERIALS AND METHODS
2.1. Description of the study region
The study area was located in Niger River in Benin
around Malanville town, located at North-East Benin at
latitude 11°52'216"N and longitude 3°21'111"E. The
Niger River (4200 km) is the third-longest river in Africa
after the Nile (6600 Km) and Congo (4700 ) (Aboubacar
and Humphrey, 2007). This river crossed nine (9) African
countries and serves as borderline between Benin and
Niger Republics. Northern Benin shows a Soudano-
Sahelian climate with a long dry season occurring from
October to April, a wet season from May to July and a
flood season from August to September (PDC Malanville,
2006) with an average annual rainfall of about 750 mm.
The dominant wind (harmattan) blows from November to
January (PDC Malanville 2006, Aboubacar and
Humphrey 2007). In Benin, the Niger River showed a
huge floodplain extending on about 300 ha that stood as
an important reproduction ground for the fishes (Moritz et
al., 2006). The main aquatic plants were Eichhornia
crassipes, Echinochloa stagnina, Pistia stratiotes, typha
australis, Mimosa sp, Mimosa pigra, paspalum
serobiculatum, Ipomoea aquatica, Cyperus cyperoides,
Ipomoea asarifolia, Senna occidentalis, Ludwigia
senegalensis, Ludwigiaabyssinica,Ludwigia adscendens,
Ludwigia erecta, Achyranthes aspera, Azolla africanaetc
(Adjibade et al., 2019a). The Niger River was intensively
exploited for artisanal fisheries by fishermen from South-
Benin, Burkina Faso, Ghana, Mali, Togo, etc. The
floodplain was used to grow rice, onion, maize,
watermelon, pepper etc. that caused severe ecological
disturbances to the river because of the use of chemical
fertlizers and pesticides (Laë et al., 2003).
2.2. Sampling sites
Marcusenius senegalensis individuals were sampled from
five sampling sites accordingto anthropogenic
disturbances. Site 1 (11°52'216"N, 11°52'216"N), located
on Sota stream, was covered by aquatic vegetation where
domestic wastes were rejected. Site 2 (11°52'112"N,
3°23'672"E) was also situated on Sota stream, at Tounga
village and was under chemical pollution because of the
use of fertilizers and pesticides in adjacent agriculture.
Site3 (11°52'675"N, 3°25'329"E) was located at Gaya
village (Niger Republic) on the main channel of Niger
River. Less degraded, Site4 (11°52'987"N, 3°20'819"E)
communicated with Alibori stream and was located on the
main channel. Site5 (11°52'970"N, 3°21'111"E) was also
located on the main channel of the river and under Benin-
Niger bridge.
3. International Journal of Forest, Animal and Fisheries Research (IJFAF)
[Vol-4, Issue-1, Jan-Feb, 2020]
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2.3. Marcusenius senegalensis sampling and
identification
Fish collections were done monthly from February 2015
to July 2016 in the aquatic vegetation habitat and in the
open water habitat at the five sampling sites. Fishing
gears such as gillnets (50 m × 1 m, 40 mm-mesh; 50 × 1
m, 30 mm-mesh; 50 m × 1 m, 20 mm-mesh), cast nets (6
m-diameter, 20 mm-mesh) and seine (6.15 m × 2 m, 16
mm-mesh) were used for collections (Adite and
Winemiller 1997; Adjibade et al. 2019a). After collection,
all harvested fishes were identified in situ using
references such as Paugy et al. (2003) and Levêque and
Paugy (2006). Fish individuals were then immediately
preserved in 10% formalin and conveyed to the
"Laboratoire d'Ecologie et de Management des
Ecosystèmes Aquatiques (LEMEA)".
2.4. Laboratory procedure
In the laboratory, after seven (7) days the fish samples
were removed from the formalin and preserved in 70%
ethanol to facilitate further manipulations. Preserved
fishes were removed from the ethanol solution and names
were confirmed using fishbase
(https://www.fishbase.org). Each individual of M.
senegalensis was measured for total length (TL) and
standard length (SL) with an accuracy of 0.1 mm using an
ichthyometer, then weighed to 0.1 g accuracy with an
electronic balance (CAMRY) and then dissected. After
dissection, gonad of each fish was removed and length,
width and weight were measured with a digital slide
caliper. Genders and gonad maturity stages were visually
examined. Like many mormyrids, males are recognized
by a clear kink (Fig. 1) in the anal fin base which is
straight and absent in females and juvenile males (Lamml
and Kramer, 2007). This kink help to determine the
maturation stage. Testes and ovaries were determined
according to the modified maturation scale of (Oduol,
1986; Ouattara et al., 2010). Females stages were : (1)
Immature –small ovary, transparent to translucent, pinkish
in color and lodged between the swim bladder and the
abdominal wall. The oocyte was indistinguishable to the
naked eye, (2) developing - ovary slightly increases in
size and occupies 20% - 30% of the abdominal cavity.
Ovary color change from pinkish to grewish due to the
accumulation of yolk in the oocytes and now
distinguishable with the unsided eye, (3) Mature (Fig. 2) -
Ovary large, yellowish and occupies a considerable part
of the abdominal cavity (4) Ripe - ovary large, yellowish
and occupies a considerable part of the abdominal cavity
and (5) Spent – flaccid (Fig. 3), with occasional residual
eggs. The color changes to dirty-brown and characterize
by empty follicles. Maturation stages of male were : (1)
Immature - the testis is small, poorly developed,
translucent, soon later the mid-point begins to acquire
slight bulging appearance, (2) developing - the testis
develops a more prominent bulge in the mid-point region
and put a greyish coloration, (3) Mature - the organ is
enlarged in his mid-point, occupies between 10 - 15% of
the abdominal cavity and become creamish but milt is not
emitted upon stripping, (4) Ripe - free flow of milt with
slight pressure on the peritoneum. The testes occupy
about 20% of the abdominal cavity, look creamish and (5)
Spent - the testis is shrunken and bloody. The oocytes of
M. senegalensis show cycloid form (Nzeh and Lawal,
2012; Paugy, 2002).
The fecundity was estimated using two methods: for small
ovaries under 1 g, complete counts were made. For larger
ovaries, a three subsample (anterior, middle and posterior)
were taken, counted, and extrapolated to the total ovary
weight. Egg diameters were measured with a calibrated
eyepiece micrometer, mounted to a dissecting
stereomicroscope. The diameters obtained were used to
construct the egg diameters frequency histogram.
Fig. 1: Individual of mature Marcusenius senegalensis male showing a kink in the anal fin base.
4. International Journal of Forest, Animal and Fisheries Research (IJFAF)
[Vol-4, Issue-1, Jan-Feb, 2020]
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Fig. 2: Individual of Marcusenius senegalensis female showing mature oocytes.
Fig. 3: Ovary of Marcusenius senegalensis female at "spent" maturation stage.
2.5. Data analysis
The sex-ratio was determined by computing the
proportion of males and females. A chi-square test
(α<0.05) was applied to verify the existence of significant
differences between the number of males and females of
M. senegalensis. The reproduction period for males and
females was established through the analyses of monthly
variations of the mean gonadosomatic index (GSI) values.
GSI =
Gonad weight (Gw)
Body weight (𝐵𝑤)
𝑥 100 (1)
Monthly average GSI was then calculated and used to
determine the spawning period of M. senegalensis. The
length at first sexual maturity (L50), defined as the length
at which 50% of the individuals of both sexes attain
maturity, was estimated by the logistic curve following
equation (Hosmer and Lemesgow, 1989):
𝑃 =
1
[1 + 𝑒−(𝑏𝑒𝑡𝑎0 + 𝑏𝑒𝑡𝑎1 ∗ 𝑋)]
(2)
where P is the probability of an individual to being mature
at a determinate X length,
beta0 (intercept) and beta1 (slope) are estimated
parameters. L50 is calculated as:
𝐿50 =
−𝑏𝑒𝑡𝑎0
𝑏𝑒𝑡𝑎1
(3)
5. International Journal of Forest, Animal and Fisheries Research (IJFAF)
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The lengths at first sexual maturity (L50) were obtained
for both genders by firstly plotting the percentage of
mature fish individuals against their total length (TL) and
by fitting a sigmoid curve to the scatter plot (Adite et al.,
2017). For this study, testes and ovaries at stage II to IV
of the maturation scale were considered sexually matures
and were used to construct the sigmoid curves (Adite et
al., 2017). Besides, for flood, wet and dry seasons, a ripe
ovary with the highest GSI were selected to design the
frequency histograms of egg diameters and to examine
egg maturationand cohort production trends (Adite et al.,
2017). Absolute fecundity was estimated for ripe ovaries
and the relationship between fecundity and body length
were examined using the following power function:
Fa =
aTLb
(4)
Where Fb is the fecundity, TL is the total length, "a" is a
constant and "b" is the slope.
Also, a linear relationship between fecundity and body
weight was examined following :
Fa = b2Bw + a2 (5)
Where Fa is the absolute fecundity, Bw is the body weight,
b2 is the slope and a2 is the intercept.
III. RESULTS
3.1. Sex-ratio and population structure
Among the 2019 individuals of M. senegalensis collected
during this study, 1032 (51.11%) were males and 987
(48.89%) were females. These abundances correspond to
a sex ratio of 1:0.96 that differs significantly from a 1:1
ratio (χ² = 53.14; p < 0.05). In the fish assemblages,
females were larger than males and the maximum sizes
recorded for both genders were TL= 280 mm (SL=248
mm, W = 217.6 g) and TL= 275 mm (SL=242 mm, W =
158.18 g), respectively. Ontogenetically, subadults and
adults dominated the fish assemblages and numerically
accounted for 59.14% and 30.51%, respectively, whereas
juveniles showed moderate abundances of 10.35%. Total
length and body weight model gave a positive allometric
coefficient b = 3.3921 with a significant (p < 0.05)
correlation coefficient r= 0.94 (Fig. 4).
Fig. 4: Length-weight relationship of Marcusenius senegalensis (n=2019) collected in Niger River (Northern Benin) from
February 2015 to July 2016.
3.2. Spawning season
During the study period and with regards to the 2019
Marcusenius senegalensis collected, individual
gonadosomatic index significantly (p < 0.001) varied in
both genders and ranged between 0.01 (TL = 251 mm, SL
= 225 mm, W = 100.1 g) and 1.12 (TL = 195 mm, SL =
172 mm, W = 53.8 g) in males and between 0.02 (TL =
195 mm, SL = 168 mm, W = 74.74 g) and 27.58 (TL=
166 mm, SL = 144 mm, W =11.28 g) in females. Monthly
gonodosomatic index (GSI) ranged between 0.04 and 6.13
(mean = 1.32 ± 1.56) for females and peaked in July and
August with GSI values reaching 6.13 and 5.88,
respectively. In males, the GSI varied between 0.03 and
0.42 (mean = 0.12 ± 0.09) and like females, peaked in
July and August with GSI = 0.37 and GSI = 0.38 (Fig. 5).
W = 0.000001TL3.3921
r = 0.94, N = 2019, p < 0.05
0
50
100
150
200
250
0 50 100 150 200 250 300
Weight(g)
Total Length (mm)
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In both genders, gonadosomatic index significantly (p <
0.001) varied with seasons. GSI value of males was
higher during the wet season (GSI = 0.26±0.26) and flood
season (GSI = 0.15±0.13) and was reduced during the dry
season (GSI = 0.09±0.06). Identical trends were recoded
for females subpopulation with the higher gonadosomatic
index recorded in the wet season (GSI = 3.66±3.91) and
flood season (GSI = 4.52±5.02) while the lowest GSI was
found during the dry season (GSI = 0.20±0.28). Also, the
highest percentage of mature males and mature females
were recorded in June, July, and August.
Fig. 5: Monthly variations of gonadosomatic index (GSI) of M. senegalensis males and females collected in Niger River
(Northern Benin) from February 2015 to July 2016.
3.3. Length at first sexual maturity
In this study, the smallest mature male measured 104 mm-
TL (90 mm, W = 6 g, GSI = 0.17) while the smallest
mature female measured 115 mm-TL (98 mm SL, W =
14.56 g, GSI = 9.48). For males and females, the scatter
plots of the percentages of mature individuals against total
length (TL) are given in Figure 6 and Figure 7,
respectively. Overall, the percentages of ripe testes and
ovaries significantly (p < 0.05) increased with total length
to reach nearly 100% at length 260-270 mm and 270-280
mm, respectively. Associated equations from the sigmoid
curve fitted to scatter plots were:
𝑃𝑚 =
1
[1 + 𝑒−(7.85 + 0.047TL)]
(6)
and
𝑃𝑓 =
1
[1 + 𝑒−(−10.05627 + 0.06139TL)]
(7)
where Pf and Pm are the probability of an individual being
mature males and mature females, respectively. Thus, the
length at first sexual maturity (L50) obtained from the
sigmoid curve were 167.89 mm for males (Fig. 6) and
163.81 mm for females (Fig. 7).
0
1
2
3
4
5
6
7
F M A M J J A S O N D J F M A M J J
Gonadosomaticindex(GSI)
Months
mean GSI Males mean GSI Females
7. International Journal of Forest, Animal and Fisheries Research (IJFAF)
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Fig. 6: Length at first sexual maturity (L50) of Marcusenius senegalensis males collected in Niger River (Northern Benin)
from February 2015 to July 2016.
Fig 7: Length at first sexual maturity (L50) of Marcusenius senegalensis females collected in Niger River (Northern Benin)
from February 2015 to July 2016.
3.4. Fecundity
In Niger River in Benin, M. senegalensis showed absolute
fecundity varying between 844 eggs for a female of 110
mm-TL (SL = 93 mm, W = 11.36, GSI = 8.27) and
12,643 eggs for a female of 248 mm-TL (SL = 211 mm,
W = 137.3, GSI = 11.96) with a mean fecundity of 3204 ±
1950 eggs. Relative fecundities varied from 43 eggs/g for
an individual of 172 mm TL, (SL =146 mm, W =47.62 g,
GSI=0.42) to 196 eggs for an individual of 166 mm TL,
(SL =144 mm, W = 40.9 g, GSI = 27.58) (Table 1). Power
curve fitted to total length-fecundity scatter plot and linear
regression fitted to body weight-fecundity scatter plot
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showed that fecundity significantly (p<0.05) increase with
total length (TL) and body weight (W) (Fig. 8 & 9). The
power (Fig. 8) and regression (Fig. 9) equations were as
follow :
Fa = 0.014TL2.8341
(r = 0.94, N = 177, p < 0.05) (Fig. 8)
Fa = 69.705W + 373.24 (r = 0.92, N = 177, p< 0.05)(Fig.
9),with r, the correlation coefficient and N, the total
number of ripe females.
Fig. 8: Power function between fecundity (Fa) and total length (TL) of Marcusenius senegalensis collected in Niger River
(Northern Benin) from February 2015 to July 2016.
Fig. 9: Linear regression between fecundity (Fa) and body weight (W) of Marcusenius senegalensis collected in Niger River
(Northern Benin) from February 2015 to July 2016.
Fa = 0.0014TL2.8341
r = 0.94, N=177, p<0.05
0
2000
4000
6000
8000
10000
12000
50 100 150 200 250 300
Numberofoocytes
Total length (mm)
Fa = 69.705W + 373.24
r = 0.92, N=177, p<0.05
0
2000
4000
6000
8000
10000
12000
14000
0 20 40 60 80 100 120 140 160 180
Numberofoocytes
Weight (g)
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Table 1: Body weight (Bw), ovary weight (Ow), mean and range of absolute and relative fecundities and gonadosomatic
index (GSI) of Marcusenius senegalensis by length classes collected in Niger river (Northern Benin) from February 2015 to
July 2016.
TL
class
N
Bw (g) Ow (g) Absolute fecundity Relative fecundity GSI
Mean±SD Mean±SD Mean±SD Range Mean±SD Range Mean±SD Range
<150 48 18.91±3.47 3.07±2.59 1,629±319 844-2,346 86±11 65-113 4.08±4.05 0.33-14.62
150-
200
106 39.10±11.95 1.17±1.83 3,092±1022 1,744-8,009 81±20 43-196 2.96±4.3 0.22-27.58
200-
250
20 80.83±20.52 3.05±3.78 6,820±2199 4,139-12,643 84±15 62-116 3.55±3.33 0.15-11.96
>250 3 140.83±27.08 1.31±1.44 8,254±1444 7,105-9,875 59±10 49-70 0.84±0.82 0.32-1.79
Total 177 40.07±25.03 1.27±2.04 3,204±3.19 844-12,643 89±10 43-196 6.25±3.63 0.15-27.58
3.5. Ovarian structure
Figure 10 shows the histogram of eggs diameter
frequency distributions during dry, wet and flood season.
Overall, M. senegalensis egg diameters ranged from 0.21
to 1.77 mm with a mean of 0.95±0.35 mm. Seasonally,
egg diameters ranged between 0.21-0.95 (mean:
0.53±0.15), 0.33-1.77 (mean: 1.09±0.29) and 0.31-1.74
(mean: 1.07±0.29) for dry, wet and flood seasons,
respectively. Also, the analysisof variance shows
significant (F2,2039 = 768.49 p < 0.001) seasonal variations
within egg diameters.
Fig. 10: Egg diameter frequency distributions for wet, flood and dry seasons of Marcusenius senegalensis collected in Niger
River (Northern Benin) from February 2015 to July 2016.
0
50
100
150
200
250
300
<0.4 0.5 0.7 0.9 0.11 0.13 0.15 >1.6
Numberofeggs
Oocyte diameters (mm)
Wet
Flood
Dry
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IV. DISCUSSION
Knowledge on life history strategy and reproduction
pattern of a fish species is crucial for spawning ground
protection, species conservation/valorization and fisheries
management. In this study, Marcusenius senegalensis
showed a sex-ratio (1:0.96) in favor of males. This trend
agreed with those reported for Gnanthonemus
senegalensis from Asa lake in Nigeria where the sex-ratio
was in favor of males with 1:0.4 (Nzeh and Lawal, 2012).
Likewise, three (3) mormyrids, Marcusenius ussheri from
Bia River in Ivory Coast, Mormyrus kannume from
Kamburu lake in Kenya, and Hyperopisus bebe from
Warri River in Nigeria showed exhibited the same pattern
with a sex-ratio of 1:0.84, 1:0.96 and 1:0.59, respectively
(Oduol, 1986; Olele, 2013; Ouattara et al., 2010).
Nevertheless, Chrysichtys nigrodigitatus (sex-ratio =
1:2.1) from Ahozon Lake, exhibited some sex-ratio in
favor of females (Adite et al., 2017). As reported by Atse
et al. (2009) and Adite et al. ( 2017), differential genetic,
behavioral and morphological characteristics of both
genders may play in favor of one sex as selective traits.
Also, gender tolerance or resistance to environmental
disturbances could affect the percentage of males and
females in the population (Olele, 2013).
Because testes were in general reduced, the
highest gonadosomatic indexes (GSI) of M. senegalensis
males (1.12) were much lower than those of females
(27.58). This trend was earlier reported by Levêque and
Paugy (2006) for most African species. The same
observation was made by Paugy (2002) in Baoule River
where Marcusenius senegalensis females showed much
higher GSI compared to those of male individuals (GSIm=
0.5; GSIf = 18.7). In Niger River, the remarkable increase
of the GSI from June (GSI=0.82), at beginning of the wet
season to reach a peak (GSI=6.13) in August is the result
of the increase of water levels that stimulated gonad
maturation and initiated spawning activities. The decrease
of the GSI from mid-September implies that the
reproduction of M. senegalensis covered the period of
June-September, the wet and flood seasons. These
spawning seasons of M. senegalensis seem to be nearly
identical for most fish species dwelling African water
bodies. Indeed, in Baoulé and Nile Rivers, Paugy (2002)
and Nawar(1959) reported that ovaries and testes started
to mature in May and continued their development to July
before stopping in September. According to Albaret
(1982), in Ivory Coast freshwater bodies, the majors
reproductions activities for Marcusenius bruyerei and
Marcusenius furcidens occurred in May and July, and
particularly when water levels increase and conductivity
decreases. In the principal course of River Bia in Ivory
Coast, Ouattara et al. (2010) reported that Marcusenius
ussheri exhibited many peaks of gonadosomatic index
during the year. Also, Jégu and Lévêque (1984) reported
that M. ussheri and M. furcidens reproduced from
September to October in Bandama River, and from
August – November in Comoé River when the water rise.
These results suggested that M. senegalensis and most of
the mormyrids displayed multiple spawning behavior
leading to the production of many offspring cohorts
during the spawning periods.
In the current study, the lengths at first sexual
maturity (L50) recorded for Marcusenius senegalensis
male and female were 167.89 mm –TL and 163.81 mm-
TL respectively, implying that females mature earlier and
males displayed delayed maturation, though both values
were not significantly (χ² = 0.053.14; p = 0.8227)
different. This finding agreed with Ouattara et al. (2010)
report, where Marcusenius ussheri females attained first
sexual maturity at 168 mm-TL while males showed
delayed maturation at 173 mm-TL. Also, males
Marcusenius macrolepidotus from the Upper Zambezi
showed sexual maturity at 12.1-15.9 cm-SL while females
reached sexual maturity at 11.8-13.6 cm-SL (Lamml and
Kramer, 2007). According to Paugy (2002), this
observation in which females mature earlier than males
were common for many African tropical fishes. As
reported by Giora et al. (2014), in species
Brachyhypopomus gauderio (Hypopomidae), males
reached first sexual maturity at 108 mm while females
mature earlier at 104.5 mm. Nevertheless, in the man-
made lake of Kamburu, Mormyrus kannume male showed
a lower size at first sexual maturity at 24.0 cm-SL
compared to females that reached maturity at a higher size
(24.8 cm-SL) (Oduol, 1986). Many authors (Blake, 1977;
Kolding et al., 1992; Kramer, 1997; Lamml and Kramer,
2007) stated that mormyrids reached their first sexual
maturity when their size exceeded 40% of the maximum
size for that species. However, according to Nikolsky
(1963), Kirschbaum and Schugardt (2002) and Paugy
(2002), environmental factors such as water temperature,
turbidity, pH, dissolved oxygen, conductivity, seasons,
food availability, habitat stochascity etc. and fishing
pressure could greatly influence the length at first sexual
maturity.
In Niger River, Marcusenius senegalensis showed a
moderate to low absolute fecundity varying between 844
eggs and 12,643 eggs averaging 3204 ±3.19 eggs. These
estimates were higher than those reported by Okedi
(1970) for Marcusenius grahami and Marcusenius
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nigricans whose fecundities in Lake Victoria in Uganda
ranged from 248 eggs to 5,229 eggs and 206 eggs to 739
eggs, respectively. In contrast,in Bia River, Ouattara et al.
(2010) reported for Marcusenius ussheri, a maximum
fecundity of 53,897 oocytes, much higher than our
findings. The positive and significant (b = 2.8341; r =
0.94; p < 0.05) power relationship between fecundity (Fa)
and total length (TL) and the linear regression (b =
69.705; r = 0.92; p < 0.05) between fecundity (Fa) and
body weight (W) indicated that fecundity increase with
total length (Fig. 8) and body weigth (Fig. 9).
With regards to egg sizes, M. senegalensis
showed oocyte diameters ranging between 0.20 mm and
1.77 mm (mean = 1.27). These values were higher than
those reported by Scheffel and Kramer (1997) and Paugy
(2002) in a river from West Africa and Baoulé River
where Marcusenius senegalensis showed average egg
diameters of 1.13 mm and 1.25 mm, respectively. In
contrast, our findings were lower than Okedi (1970)
records in Lake Victoria where oocyte diameters ranged
between 1.3-1.8 m (mean = 1.52 mm) and between 2.1-
2.9 mm (mean = 2.38 mm) for Marcusenius grahami and
Marcusenius nigricans, respectively. Also, Ouattara et al.
(2010) reported in Bia River, a higher egg diameters for
Marcusenius ussheri (mean = 1.81 mm). Likewise, our
findings were lower than those reported by Blake (1977)
for Marcusenius senegalensis measuring (0.1-1.35 mm),
Campylomormyrus tamandua (0.1-1.5 mm), Mormyrops
deliciosus (0.1-1.9 mm), Hyperopisus bebe (0.1-1.58 mm)
and Hippopotamyrus pictus (0.1-1.78 mm). In general, as
stated by Obota et al. (2016), oocyte diameter vary with
species and are affected by fish size, growth, density, food
availability and mortality. According to Idowu (2017),
egg diameters are greatly influenced by environmental
factors such as physicochemical parameters and food
availability.
In the current study, Marcusenius senegalensis
showed moderate maximum sizes, TL= 275 mm and TL=
280 mm for males and females, respectively. The smallest
mature male and female measured 104 mm-TL and 115
mm-TL, respectively and lengths at first sexual maturity
(L50) were 167.89 mm –TL for males and 163.81 mm-TL
for females. These imply that this mormyrid displayed an
moderately delayed reproduction associated with
moderate to low fecundity (844-12,643 eggs). During wet
and flood seasons (June-September), egg diameters
frequencies showed that ovaries comprised oocytes at all
maturity stages, indicating a repeated spawning leading to
multiple cohort productions with a relatively high
recruitment and recolonization. Kirschbaum and
Schugardt (2002) and Paugy (2002) confirmed this trend
and reported that M. senegalensis is a fractional spawner
with an average of 2000 eggs laid at each spawning.
These reproduction traits suggest that M. senegalensis
displayed a life history strategy between r and K, but
more inclined towards K-selected.
Like other mormyrids, M. senegalensisseems to
be well adapted to the changing conditions of their
environment. The spawning occurred with the increase of
water levels and the decrease of conductivity stimulate
gonad development. Thus, the reproduction is linked to
the beginning of the rain and the flood (Hopkins, 1986).
V. CONCLUSION
The current study documented some aspects of the
reproductive biology of Marcusenius senegalensis from
Niger River in Benin where mormyrids constitute highly
commercial and economic fisheries resources. In this
running water, M. senegalensis males dominated the
population and the species showed a moderately delayed
maturation with lengths at first sexual maturity reaching
167.89 mm-TL for males and 163.81 mm-TL for females.
Gonadosomatic index peaked in August and reproduction
occurredfromJune to September in the wet and flood
periods. Fecundities were moderate to low and
significantly (p < 0.05) increased with total length and
body weight. The species showed a multi-spawning
behavior and displayed a life history strategy between r
and K, but more inclined towards K-selected. The current
findings will serve as tools for species follow up,
management and sustainable exploitation.
ACKNOWLEDGEMENT
The authors would like to express their gratitude to the
Government of the Republic of Benin for providing us a
grant through the program "Appui aux Doctorants" and to
the "Laboratoire d’Ecologie et de Management des
Ecosystèmes Aquatiques (LEMEA)", University of
Abomey-Calavi for its logistic assistance. Special thank to
Oussa Abigail for her assistance in data collection and to
all the fishermen and fisherwomen who help us during the
different samplings missions conducted in the Niger River
at Malanville.
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