This document analyzes population dynamics of 10 benthic shellfish species commercially fished along northern Chile. Time series data from 1998-2005 on catch per unit effort (CPUE) were used to model annual population growth rates. Models incorporated both endogenous density-dependent factors and exogenous oceanographic factors including sea surface temperature, Southern Oscillation Index, and upwelling index. The best models for each species explained a high percentage (average 88%) of variance in population growth rates and included effects of both endogenous and exogenous factors, indicating populations are regulated by intraspecific interactions and physical forcing during early life stages. Results highlight the importance of considering both endogenous and exogenous factors in models to better understand natural population regulation and
This review analyzes 214 published phylogeography studies of South American organisms to identify emerging patterns. The studies find striking genetic divergence among lineages, suggesting high undocumented diversity. Pleistocene climate oscillations and Pliocene/Miocene geological events shaped modern distributions in tropical and temperate regions. Herpetofauna diverged earlier than other groups. Forest species' ranges contracted more in glacial periods, while open habitat species responded variably to climate change. The results reveal a complex mosaic of phylogeography patterns across South America.
Alex_Brown_MRes_thesis_compiled_21_Aug_2006Alex Brown
This document summarizes a research project investigating the distribution of small pelagic fish in Spanish Mediterranean waters. The study uses environmental modelling, essential fish habitat mapping, and geostatistics to analyze the influence of environmental factors on fish distribution. The document provides background on how abiotic factors like temperature and salinity indirectly relate to fish distribution by influencing prey availability. It also describes methods used, including general additive models to relate fish presence/absence and abundance to environmental variables, geographic information systems to map essential fish habitat, and geostatistical techniques like variograms and kriging to analyze spatial structure of fish populations and estimate total abundance. The study focuses on commercially important small pelagic fish in the region like sardine and
Do fine-scale factors shape the use of riparian galleries by carnivores in a ...Agriculture Journal IJOEAR
Abstract— Riparian galleries are key structural elements of Mediterranean landscapes and their importance for carnivores has been widely demonstrated. However, humanization of the landscape has led to their degradation with consequences not fully understood. In this study we assessed the response of mesocarnivores to the fine-scale variation in the quality of a riparian gallery (Vale do Cobrão stream, central Portugal), evaluated on the basis of the QBR index (‘Qualitat del Bosc de Ribera’ in spanish) and an adaptation of the same considering mesocarnivore ecological requirements. These were represented through four parameters that could influence habitat quality for these species, namely refuge (total riparian cover, cover structure), disturbance and food availability. For the latter we considered the known main food resources for Mediterranean mesocarnivores: small mammals, lagomorphs, insects and fruits. Mesocarnivore use was evaluated through camera-trapping and sign surveys. For both indexes a concordance was observed between quality variation and its use by carnivores, and we also found a positive correlation between both indexes. The adapted QBR, being more laborious but also more realistic, could serve as guidance for conservation practice at the local scale, benefiting both land managers environmentally concerned, conservation practitioners and carnivore populations inhabiting humanized landscapes. However, for spatially wider approaches the original QBR proved to be a good indicator for the presence of mesocarnivores, being useful in the development of restauration or conservation strategies, as well as for research and monitoring activities of carnivore guilds.
The El Palto Phase of Northern Perú: Cultural Diversity in the Late Pleistocene-Early Holocene
La Fase El Palto en el Norte de Perú: Diversidad Cultural en el Pleistoceno Tardío-Holoceno Temprano
Greg J. Maggard
Atlantic Bluefin Tuna: Ecological based management of highly migratory tuna u...Nathaniel Newlands
Integrated monitoring, modeling, assessment of highly-migratory fish populations using spatially-explicit, ecological-based prediction models, artificial intelligence, and big data:
The Atlantic bluefin tuna (Thunnus thynnus) is a long-lived, highly migratory species that attain sizes of 2.20 m, weights of 650 kg or more, and live over 32 years. Adults undertake cyclic migrations between coastal feeding zones, offshore wintering areas and spawning grounds. During June through October, bluefin tuna are common off the eastern United States and Canada, entering the Gulf of Maine/Gulf of St. Lawrence, a semi-enclosed continental shelf area. Bluefin migrate seasonally up to this region as adults from the Gulf of Mexico, which is the only known spawning area for the Western Atlantic population. Tagging studies reveal bluefin or many different ages regularly undertake large-scale migrations (7400 km or more) across the Atlantic.
The International Commission for the Conservation of Atlantic Tunas (ICCAT) has adopted an interim conservation and management plan for 2018-2020, having been unable to determine population status following a 20-year rebuilding plan. The recent NOAA stock assessment (2017) indicates that the western Atlantic population is not being overfished, but has an unknown overfished status, with spawning stock biomass increasing since 2004.
Spatial population assessments and models of Atlantic bluefin are primarily based on catch rate data, with assumptions that are typically insufficient for capturing real temporal and spatial shifts in their distribution, especially under large inter-annual biotic and abiotic variability and uncertainty. Reliable current and future population estimates incorporating new fishery-independent indices are therefore urgently needed to better explain and track changes in seasonal abundances and trans-Atlantic stock mixing. Using such indices, a new operational management strategy for this species could be designed that is linked to a broader evidence based involving “Big data” from vessel, airborne, and satellite-based monitoring data. This new strategy could incorporate more realistic and robust assumptions linked with their behavioral ecology (schooling, finding prey, preferred ocean conditions) and changing ocean conditions due to climate change.
In this presentation, I provide a summary of modeling research work in modeling of bluefin tuna population dynamics - from individual to school to population scales – which revealed new information and insights on their movement and behavior. This work developed a novel statistical population assessment approach and a spatially-explicit individual-based prediction model integrating new information from tracking, tagging, and survey data.
Sharks are top predators, but little was known about bonnethead sharks' feeding ecology in Tampa Bay. The author studied the diets of 13 bonnethead sharks captured in Tampa Bay. The study found the main dietary components were blue crab, common spider crab, and seagrass, with seagrass having the highest index of relative importance. While seagrass made up most of the diets numerically, it is unclear if bonnetheads actively forage seagrass. More research with larger sample sizes is needed to better understand bonnethead feeding ecology in Tampa Bay and determine if environmental changes have impacted their diets.
Terminal Pleistocene Lithic Technology and Use of Space in Central Chile
Tecnología Lítica y Uso del Espacio del Pleistoceno Terminal en el Centro de Chile
César Méndez and Donald Jackson
1) The modeling framework presented integrates remotely sensed observations of agricultural activity with an agroeconomic model calibrated using Positive Mathematical Programming to predict how drought impacts crop mix, land use, water availability, and farmer decision-making.
2) An ensemble Kalman filter is used to recursively estimate parameters of the agronomic production function based on satellite data assimilation, allowing evaluation of predictive uncertainty.
3) The approach permits operationalizing new earth observation capabilities to inform agricultural and water policy questions around land and water use changes from drought.
This review analyzes 214 published phylogeography studies of South American organisms to identify emerging patterns. The studies find striking genetic divergence among lineages, suggesting high undocumented diversity. Pleistocene climate oscillations and Pliocene/Miocene geological events shaped modern distributions in tropical and temperate regions. Herpetofauna diverged earlier than other groups. Forest species' ranges contracted more in glacial periods, while open habitat species responded variably to climate change. The results reveal a complex mosaic of phylogeography patterns across South America.
Alex_Brown_MRes_thesis_compiled_21_Aug_2006Alex Brown
This document summarizes a research project investigating the distribution of small pelagic fish in Spanish Mediterranean waters. The study uses environmental modelling, essential fish habitat mapping, and geostatistics to analyze the influence of environmental factors on fish distribution. The document provides background on how abiotic factors like temperature and salinity indirectly relate to fish distribution by influencing prey availability. It also describes methods used, including general additive models to relate fish presence/absence and abundance to environmental variables, geographic information systems to map essential fish habitat, and geostatistical techniques like variograms and kriging to analyze spatial structure of fish populations and estimate total abundance. The study focuses on commercially important small pelagic fish in the region like sardine and
Do fine-scale factors shape the use of riparian galleries by carnivores in a ...Agriculture Journal IJOEAR
Abstract— Riparian galleries are key structural elements of Mediterranean landscapes and their importance for carnivores has been widely demonstrated. However, humanization of the landscape has led to their degradation with consequences not fully understood. In this study we assessed the response of mesocarnivores to the fine-scale variation in the quality of a riparian gallery (Vale do Cobrão stream, central Portugal), evaluated on the basis of the QBR index (‘Qualitat del Bosc de Ribera’ in spanish) and an adaptation of the same considering mesocarnivore ecological requirements. These were represented through four parameters that could influence habitat quality for these species, namely refuge (total riparian cover, cover structure), disturbance and food availability. For the latter we considered the known main food resources for Mediterranean mesocarnivores: small mammals, lagomorphs, insects and fruits. Mesocarnivore use was evaluated through camera-trapping and sign surveys. For both indexes a concordance was observed between quality variation and its use by carnivores, and we also found a positive correlation between both indexes. The adapted QBR, being more laborious but also more realistic, could serve as guidance for conservation practice at the local scale, benefiting both land managers environmentally concerned, conservation practitioners and carnivore populations inhabiting humanized landscapes. However, for spatially wider approaches the original QBR proved to be a good indicator for the presence of mesocarnivores, being useful in the development of restauration or conservation strategies, as well as for research and monitoring activities of carnivore guilds.
The El Palto Phase of Northern Perú: Cultural Diversity in the Late Pleistocene-Early Holocene
La Fase El Palto en el Norte de Perú: Diversidad Cultural en el Pleistoceno Tardío-Holoceno Temprano
Greg J. Maggard
Atlantic Bluefin Tuna: Ecological based management of highly migratory tuna u...Nathaniel Newlands
Integrated monitoring, modeling, assessment of highly-migratory fish populations using spatially-explicit, ecological-based prediction models, artificial intelligence, and big data:
The Atlantic bluefin tuna (Thunnus thynnus) is a long-lived, highly migratory species that attain sizes of 2.20 m, weights of 650 kg or more, and live over 32 years. Adults undertake cyclic migrations between coastal feeding zones, offshore wintering areas and spawning grounds. During June through October, bluefin tuna are common off the eastern United States and Canada, entering the Gulf of Maine/Gulf of St. Lawrence, a semi-enclosed continental shelf area. Bluefin migrate seasonally up to this region as adults from the Gulf of Mexico, which is the only known spawning area for the Western Atlantic population. Tagging studies reveal bluefin or many different ages regularly undertake large-scale migrations (7400 km or more) across the Atlantic.
The International Commission for the Conservation of Atlantic Tunas (ICCAT) has adopted an interim conservation and management plan for 2018-2020, having been unable to determine population status following a 20-year rebuilding plan. The recent NOAA stock assessment (2017) indicates that the western Atlantic population is not being overfished, but has an unknown overfished status, with spawning stock biomass increasing since 2004.
Spatial population assessments and models of Atlantic bluefin are primarily based on catch rate data, with assumptions that are typically insufficient for capturing real temporal and spatial shifts in their distribution, especially under large inter-annual biotic and abiotic variability and uncertainty. Reliable current and future population estimates incorporating new fishery-independent indices are therefore urgently needed to better explain and track changes in seasonal abundances and trans-Atlantic stock mixing. Using such indices, a new operational management strategy for this species could be designed that is linked to a broader evidence based involving “Big data” from vessel, airborne, and satellite-based monitoring data. This new strategy could incorporate more realistic and robust assumptions linked with their behavioral ecology (schooling, finding prey, preferred ocean conditions) and changing ocean conditions due to climate change.
In this presentation, I provide a summary of modeling research work in modeling of bluefin tuna population dynamics - from individual to school to population scales – which revealed new information and insights on their movement and behavior. This work developed a novel statistical population assessment approach and a spatially-explicit individual-based prediction model integrating new information from tracking, tagging, and survey data.
Sharks are top predators, but little was known about bonnethead sharks' feeding ecology in Tampa Bay. The author studied the diets of 13 bonnethead sharks captured in Tampa Bay. The study found the main dietary components were blue crab, common spider crab, and seagrass, with seagrass having the highest index of relative importance. While seagrass made up most of the diets numerically, it is unclear if bonnetheads actively forage seagrass. More research with larger sample sizes is needed to better understand bonnethead feeding ecology in Tampa Bay and determine if environmental changes have impacted their diets.
Terminal Pleistocene Lithic Technology and Use of Space in Central Chile
Tecnología Lítica y Uso del Espacio del Pleistoceno Terminal en el Centro de Chile
César Méndez and Donald Jackson
1) The modeling framework presented integrates remotely sensed observations of agricultural activity with an agroeconomic model calibrated using Positive Mathematical Programming to predict how drought impacts crop mix, land use, water availability, and farmer decision-making.
2) An ensemble Kalman filter is used to recursively estimate parameters of the agronomic production function based on satellite data assimilation, allowing evaluation of predictive uncertainty.
3) The approach permits operationalizing new earth observation capabilities to inform agricultural and water policy questions around land and water use changes from drought.
This document provides a literature review of 29 articles that studied green sea turtle diving behavior using electronic devices. It discusses the history of sea turtle behavior studies, comparing the use of satellite loggers and time-depth recorders to collect dive data. The definitions of behaviors like foraging and resting are examined. Additional factors discussed include study locations, sample sizes, and ecological influences on dive behavior. The review considers how these various methodological factors must be accounted for when analyzing dive behavior studies.
This thesis examines population dynamics of Northern Cardinals and Carolina Wrens in an urban forest fragment using capture-mark-recapture analysis of data collected from 2010-2014. The study aims to determine if the forest fragment acts as a safe refuge or ecological trap for these species. Capture-mark-recapture was used to estimate survival, recruitment, and population growth rates as a function of sex, age, body size, season, and year. Results will help understand how these species persist in small habitat fragments and identify life stages most impacting population persistence to inform conservation efforts.
The document discusses several projects at the MIT Media Lab focused on developing sensory prosthetics and responsive environments to enhance human perception and interaction. These include projects developing gesture recognition floors, adaptive lighting control, wrist-worn sensors, personalized building comfort control, and more. The projects involve collaborations between MIT, government agencies, non-profits, and private companies with the goal of creating technologies that extend human senses.
This document discusses the limitations of using skeletal part profiles for zooarchaeological analysis and interpretations. It argues that skeletal part profiles are an ambiguous taphonomic tool due to equifinality, where different processes can lead to the same end results. Many Paleolithic sites are palimpsests representing accumulation from multiple agents over time. Dual-process experiments show how original human accumulations can be distorted by subsequent carnivore activity. The document concludes that skeletal part profiles have limited value for zooarchaeology and that alternative taphonomic techniques like studying bone surface modifications may provide more diagnostic information.
ABSTRACT- Order siluriformes, Bagridae family of four number of catfish species provides information on the diets of
Mystus bleekeri, Mystus cavasius, Mystus tengara, Mystus vittatus in Lower Manair reservoir. The total of 1021 fish
species examined and their stomach content was analyzed. The frequency of occurrence and numerical methods were
employed in this study. In the numerical analysis, crustaceans and insect parts (85.91%) constituted the most important
diet of Mystus bleekeri followed by fish remains (78.40%), plant materials (69.01%), algae/ protozoan (64.79%), molluscs
(63.38%), detritus (56.81%) and sand grains (33.80%). The number of food items were enumerated for the crustaceans
and insect parts in Mystus bleekeri have been contained the maximum percentage (34.84%) of the content under
frequency of occurrence method followed by algae and protozoan with 20.76%, Molluscs with 18.37%, plant materials
with 15.60% and sand grains with 10.44%. The result of the analysis showed that Mystus cavasius, Mystus tengara,
Mystus vittatus fed on similar food items. These were mainly crustaceans, molluscans, fish remains and macrophytes.
Other food items include algae, detritus, sand grains. These four species are omnivorous and occupy the same ecological
niche.
Key-words- Cat fish, Food and feeding, Frequency, Numerical method
John F. Schalles is a full professor in the Biology Department at Creighton University who specializes in remote sensing of aquatic ecosystems. He has over 30 years of experience conducting research using remote sensing to analyze phytoplankton, salt marshes, and other coastal environments. He has advised over 100 undergraduate students and 16 graduate students, and has received over $1.45 million in research funding from agencies like NSF, NASA, and NOAA.
This document provides a thesis on analyzing pasture growth through herbage mass and accumulation rate. It presents research objectives to develop growth curve models, investigate seasonal patterns in parameters, create a model to predict accumulation rate based on standing mass, validate the model with defoliation treatments, and examine rising plate meter calibration factors. Herbage mass was measured weekly over 11-12 periods at three locations in 2008. Data were fit to Gompertz growth curves and time-independent relationships between accumulation rate and mass were determined. The optimum mass for maximum rate varied from 1600-4000 kg DM ha-1. Parameters were used to develop a spreadsheet model tested from May to October 2009 with defoliation treatment plots. Calibration of the rising plate
Aspects of the Geomorphology and Limnology of some molluscinhabited freshwate...iosrjce
This document summarizes a study of the geomorphology and limnology of 25 freshwater bodies in northern Nigeria that are inhabited by molluscs. A total of 14 mollusc species from 9 families were found across the water bodies. Measurements of the water bodies showed variations in elevation, size, substrate, and vegetation. Water quality parameters like temperature, pH, dissolved oxygen, alkalinity, and hardness also varied significantly between sites. Linear regression analysis revealed relationships between elevation and other factors. Canonical correspondence analysis established relationships between mollusc distributions and environmental characteristics. The study provides information on the habitats and water quality conditions of mollusc-inhabited freshwaters in northern Nigeria.
1) The success of assisted colonization and gene flow conservation strategies depends on how plant species respond to changes in temperature and photoperiod across their life cycles.
2) A study exposed seeds from northern and southern populations of an annual plant, Chamaecrista fasciculata, to ambient and elevated temperatures in a potential future colonization site north of its current range to examine responses.
3) They found warming advanced development and compressed life cycles, with patterns of selection on traits changing. Performance depended on population of origin, with the northern population faring best under current conditions but the southern population potentially adapting best to future warming. However, photoperiod mismatches may limit long-term persistence, especially between
morris and glasgow 2001 wb 113-202-210 AMREJamin Glasgow
American Redstarts were studied during spring and fall migration on Appledore Island, Maine from 1990 to 1999. Several key differences were observed between seasons:
- In spring, males arrived earlier than females and adults arrived earlier than young birds. In fall, arrival times did not differ between males and females or adults and young.
- Recaptures of banded birds occurring at least one day after initial capture were more common in fall than spring.
- While minimum stopover lengths did not differ between seasons, recaptured birds increased in mass more significantly during fall stopovers compared to spring.
- Rates of mass increase estimated by regression, however, were greater during spring stopovers than fall.
This document discusses a study that used autonomous ocean gliders to monitor the extent of hypoxia, or low dissolved oxygen levels, in the northern Gulf of Mexico. The hypoxic zone is driven by nutrient inputs from the Mississippi River that fuel phytoplankton growth, and stratification that prevents oxygen replenishment at depth. The goals of the study were to operate multiple gliders to objectively map the hypoxic zone and test their performance. Glider data on conductivity, temperature, depth, chlorophyll, colored dissolved organic matter, and dissolved oxygen were analyzed and showed the gliders could successfully find the pycnocline below which hypoxia occurs.
The document summarizes the Gila River Basin Native Fishes Conservation Program, which was established to conserve native fishes and manage against nonnative fishes in the Gila River basin in response to Endangered Species Act biological opinions. The program provides over $16 million over 30 years for conservation actions of priority native fish species and control of nonnative species. It is directed by the U.S. Fish and Wildlife Service and U.S. Bureau of Reclamation, in cooperation with state wildlife agencies, and focuses on recovery of federally-listed species through projects to prevent extinction, replicate rare populations, and control threats from nonnative species.
Critical Assessment of Claims Regarding Management of Feral Cats by Trap Neut...HVCClibrary
This document provides a critical assessment of claims made by advocates of trap-neuter-return (TNR) programs for managing feral cat populations. The authors analyze common arguments put forth by TNR advocates and find that the scientific literature contradicts each of these claims. Specifically, the authors dispute claims that feral cats only harm wildlife on islands and not continents, that they fill a natural ecological niche, and that TNR effectively eliminates feral cat colonies over time. The authors argue that TNR should be viewed as an environmental issue and receive formal environmental assessment, and that conservation scientists have an important role to play in communicating sound scientific information on this topic.
Fishery-dependent data collection provides valuable information for fishery managers to develop management plans. It is important for managers to determine the most important data to collect and implement a data recording system before overfishing occurs. One common mistake is waiting until populations are imperiled before creating management plans. This document discusses various methods for collecting fishery-dependent data, including catch estimates, catch disposition, catch per unit effort (CPUE), and fishing effort measures. It provides examples of calculating CPUE for different gear types like gill nets and longlines. The document also covers raising factors used to expand sample data to total population estimates.
Lesley Blumberg has been a successful Girl Scout cookie seller since first grade. She believes making a personal connection with customers is key to selling cookies. By telling her story of being a busy teen involved with Girl Scouts, she makes customers feel like they are supporting more than just cookie sales. One lesson she's learned is the importance of making customers feel involved in the sale and that they are buying into the Girl Scout experience.
The document provides guidelines for the visual identity of the Five Zero Nine Wine Company. It includes suggestions for logos, typography, color palettes, design elements, and photos. The style is meant to be natural, unpretentious, and emphasize the sense of place through imagery and textures that showcase the Walla Walla wine region and winemaking process.
This document discusses branding strategies and outlines a process for developing an authentic brand strategy. It recommends discovering the truthful values of a company through understanding employees and customers. A four-step process is outlined: get information, integrate it, develop the strategy, and deploy it company-wide using various tools to communicate the brand internally. Authenticity and delivering on promises are emphasized over wishful thinking or outdated traditional branding approaches.
The document discusses Jann Sabin's tips for real networking and building business relationships. Some key points include being honest, open-minded, and authentic; choosing clients carefully; managing expectations and over-delivering; not being greedy or gossiping; and ensuring relationships are maintained even if partnerships end. The overall message is that trustworthy, collaborative relationships are essential for business success.
The document discusses the growth of foreign exchange markets in India since liberalization in the early 1990s. It notes that monthly trading volumes have grown over ten times from 2003-2004 to over $359 billion in 2005-2006, making it one of the largest financial markets in India. The market is dominated by inter-bank trading among over 90 authorized dealers, mostly banks. Foreign exchange regulation has been replaced with more flexible rules, and India has moved to a managed floating exchange rate system while accumulating large foreign reserves.
The document contains advice from Jann Sabin on developing and discovering creative ideas. Some of the key points discussed include: having a map or plan but being open to detours and unexpected discoveries; getting started on an idea immediately rather than procrastinating; considering other perspectives even if they contradict your own; keeping creative teams small to allow for innovative solutions without dilution; and using unconventional or unexpected words to describe an idea in a way that can't be misunderstood. The document encourages active listening, front-loading your mind with information, trusting your instincts, and reframing problems in imaginative ways.
This document provides a literature review of 29 articles that studied green sea turtle diving behavior using electronic devices. It discusses the history of sea turtle behavior studies, comparing the use of satellite loggers and time-depth recorders to collect dive data. The definitions of behaviors like foraging and resting are examined. Additional factors discussed include study locations, sample sizes, and ecological influences on dive behavior. The review considers how these various methodological factors must be accounted for when analyzing dive behavior studies.
This thesis examines population dynamics of Northern Cardinals and Carolina Wrens in an urban forest fragment using capture-mark-recapture analysis of data collected from 2010-2014. The study aims to determine if the forest fragment acts as a safe refuge or ecological trap for these species. Capture-mark-recapture was used to estimate survival, recruitment, and population growth rates as a function of sex, age, body size, season, and year. Results will help understand how these species persist in small habitat fragments and identify life stages most impacting population persistence to inform conservation efforts.
The document discusses several projects at the MIT Media Lab focused on developing sensory prosthetics and responsive environments to enhance human perception and interaction. These include projects developing gesture recognition floors, adaptive lighting control, wrist-worn sensors, personalized building comfort control, and more. The projects involve collaborations between MIT, government agencies, non-profits, and private companies with the goal of creating technologies that extend human senses.
This document discusses the limitations of using skeletal part profiles for zooarchaeological analysis and interpretations. It argues that skeletal part profiles are an ambiguous taphonomic tool due to equifinality, where different processes can lead to the same end results. Many Paleolithic sites are palimpsests representing accumulation from multiple agents over time. Dual-process experiments show how original human accumulations can be distorted by subsequent carnivore activity. The document concludes that skeletal part profiles have limited value for zooarchaeology and that alternative taphonomic techniques like studying bone surface modifications may provide more diagnostic information.
ABSTRACT- Order siluriformes, Bagridae family of four number of catfish species provides information on the diets of
Mystus bleekeri, Mystus cavasius, Mystus tengara, Mystus vittatus in Lower Manair reservoir. The total of 1021 fish
species examined and their stomach content was analyzed. The frequency of occurrence and numerical methods were
employed in this study. In the numerical analysis, crustaceans and insect parts (85.91%) constituted the most important
diet of Mystus bleekeri followed by fish remains (78.40%), plant materials (69.01%), algae/ protozoan (64.79%), molluscs
(63.38%), detritus (56.81%) and sand grains (33.80%). The number of food items were enumerated for the crustaceans
and insect parts in Mystus bleekeri have been contained the maximum percentage (34.84%) of the content under
frequency of occurrence method followed by algae and protozoan with 20.76%, Molluscs with 18.37%, plant materials
with 15.60% and sand grains with 10.44%. The result of the analysis showed that Mystus cavasius, Mystus tengara,
Mystus vittatus fed on similar food items. These were mainly crustaceans, molluscans, fish remains and macrophytes.
Other food items include algae, detritus, sand grains. These four species are omnivorous and occupy the same ecological
niche.
Key-words- Cat fish, Food and feeding, Frequency, Numerical method
John F. Schalles is a full professor in the Biology Department at Creighton University who specializes in remote sensing of aquatic ecosystems. He has over 30 years of experience conducting research using remote sensing to analyze phytoplankton, salt marshes, and other coastal environments. He has advised over 100 undergraduate students and 16 graduate students, and has received over $1.45 million in research funding from agencies like NSF, NASA, and NOAA.
This document provides a thesis on analyzing pasture growth through herbage mass and accumulation rate. It presents research objectives to develop growth curve models, investigate seasonal patterns in parameters, create a model to predict accumulation rate based on standing mass, validate the model with defoliation treatments, and examine rising plate meter calibration factors. Herbage mass was measured weekly over 11-12 periods at three locations in 2008. Data were fit to Gompertz growth curves and time-independent relationships between accumulation rate and mass were determined. The optimum mass for maximum rate varied from 1600-4000 kg DM ha-1. Parameters were used to develop a spreadsheet model tested from May to October 2009 with defoliation treatment plots. Calibration of the rising plate
Aspects of the Geomorphology and Limnology of some molluscinhabited freshwate...iosrjce
This document summarizes a study of the geomorphology and limnology of 25 freshwater bodies in northern Nigeria that are inhabited by molluscs. A total of 14 mollusc species from 9 families were found across the water bodies. Measurements of the water bodies showed variations in elevation, size, substrate, and vegetation. Water quality parameters like temperature, pH, dissolved oxygen, alkalinity, and hardness also varied significantly between sites. Linear regression analysis revealed relationships between elevation and other factors. Canonical correspondence analysis established relationships between mollusc distributions and environmental characteristics. The study provides information on the habitats and water quality conditions of mollusc-inhabited freshwaters in northern Nigeria.
1) The success of assisted colonization and gene flow conservation strategies depends on how plant species respond to changes in temperature and photoperiod across their life cycles.
2) A study exposed seeds from northern and southern populations of an annual plant, Chamaecrista fasciculata, to ambient and elevated temperatures in a potential future colonization site north of its current range to examine responses.
3) They found warming advanced development and compressed life cycles, with patterns of selection on traits changing. Performance depended on population of origin, with the northern population faring best under current conditions but the southern population potentially adapting best to future warming. However, photoperiod mismatches may limit long-term persistence, especially between
morris and glasgow 2001 wb 113-202-210 AMREJamin Glasgow
American Redstarts were studied during spring and fall migration on Appledore Island, Maine from 1990 to 1999. Several key differences were observed between seasons:
- In spring, males arrived earlier than females and adults arrived earlier than young birds. In fall, arrival times did not differ between males and females or adults and young.
- Recaptures of banded birds occurring at least one day after initial capture were more common in fall than spring.
- While minimum stopover lengths did not differ between seasons, recaptured birds increased in mass more significantly during fall stopovers compared to spring.
- Rates of mass increase estimated by regression, however, were greater during spring stopovers than fall.
This document discusses a study that used autonomous ocean gliders to monitor the extent of hypoxia, or low dissolved oxygen levels, in the northern Gulf of Mexico. The hypoxic zone is driven by nutrient inputs from the Mississippi River that fuel phytoplankton growth, and stratification that prevents oxygen replenishment at depth. The goals of the study were to operate multiple gliders to objectively map the hypoxic zone and test their performance. Glider data on conductivity, temperature, depth, chlorophyll, colored dissolved organic matter, and dissolved oxygen were analyzed and showed the gliders could successfully find the pycnocline below which hypoxia occurs.
The document summarizes the Gila River Basin Native Fishes Conservation Program, which was established to conserve native fishes and manage against nonnative fishes in the Gila River basin in response to Endangered Species Act biological opinions. The program provides over $16 million over 30 years for conservation actions of priority native fish species and control of nonnative species. It is directed by the U.S. Fish and Wildlife Service and U.S. Bureau of Reclamation, in cooperation with state wildlife agencies, and focuses on recovery of federally-listed species through projects to prevent extinction, replicate rare populations, and control threats from nonnative species.
Critical Assessment of Claims Regarding Management of Feral Cats by Trap Neut...HVCClibrary
This document provides a critical assessment of claims made by advocates of trap-neuter-return (TNR) programs for managing feral cat populations. The authors analyze common arguments put forth by TNR advocates and find that the scientific literature contradicts each of these claims. Specifically, the authors dispute claims that feral cats only harm wildlife on islands and not continents, that they fill a natural ecological niche, and that TNR effectively eliminates feral cat colonies over time. The authors argue that TNR should be viewed as an environmental issue and receive formal environmental assessment, and that conservation scientists have an important role to play in communicating sound scientific information on this topic.
Fishery-dependent data collection provides valuable information for fishery managers to develop management plans. It is important for managers to determine the most important data to collect and implement a data recording system before overfishing occurs. One common mistake is waiting until populations are imperiled before creating management plans. This document discusses various methods for collecting fishery-dependent data, including catch estimates, catch disposition, catch per unit effort (CPUE), and fishing effort measures. It provides examples of calculating CPUE for different gear types like gill nets and longlines. The document also covers raising factors used to expand sample data to total population estimates.
Lesley Blumberg has been a successful Girl Scout cookie seller since first grade. She believes making a personal connection with customers is key to selling cookies. By telling her story of being a busy teen involved with Girl Scouts, she makes customers feel like they are supporting more than just cookie sales. One lesson she's learned is the importance of making customers feel involved in the sale and that they are buying into the Girl Scout experience.
The document provides guidelines for the visual identity of the Five Zero Nine Wine Company. It includes suggestions for logos, typography, color palettes, design elements, and photos. The style is meant to be natural, unpretentious, and emphasize the sense of place through imagery and textures that showcase the Walla Walla wine region and winemaking process.
This document discusses branding strategies and outlines a process for developing an authentic brand strategy. It recommends discovering the truthful values of a company through understanding employees and customers. A four-step process is outlined: get information, integrate it, develop the strategy, and deploy it company-wide using various tools to communicate the brand internally. Authenticity and delivering on promises are emphasized over wishful thinking or outdated traditional branding approaches.
The document discusses Jann Sabin's tips for real networking and building business relationships. Some key points include being honest, open-minded, and authentic; choosing clients carefully; managing expectations and over-delivering; not being greedy or gossiping; and ensuring relationships are maintained even if partnerships end. The overall message is that trustworthy, collaborative relationships are essential for business success.
The document discusses the growth of foreign exchange markets in India since liberalization in the early 1990s. It notes that monthly trading volumes have grown over ten times from 2003-2004 to over $359 billion in 2005-2006, making it one of the largest financial markets in India. The market is dominated by inter-bank trading among over 90 authorized dealers, mostly banks. Foreign exchange regulation has been replaced with more flexible rules, and India has moved to a managed floating exchange rate system while accumulating large foreign reserves.
The document contains advice from Jann Sabin on developing and discovering creative ideas. Some of the key points discussed include: having a map or plan but being open to detours and unexpected discoveries; getting started on an idea immediately rather than procrastinating; considering other perspectives even if they contradict your own; keeping creative teams small to allow for innovative solutions without dilution; and using unconventional or unexpected words to describe an idea in a way that can't be misunderstood. The document encourages active listening, front-loading your mind with information, trusting your instincts, and reframing problems in imaginative ways.
4.Influence of stocking density on production and water quality of a photo-he...earambulm3
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- Five stocking densities were tested (100, 300, 500, 700, 900 shrimp/m3) and water quality, growth, and survival were measured over 98 days.
- Results showed water quality was maintained at all densities but higher densities had increased TAN, nitrate, and phosphorus levels. Growth and survival decreased at densities over 300 shrimp/m3. The 500 shrimp/m3 density achieved the highest biomass and production.
This document summarizes a journal article about fisheries sustainability in Oman. It provides background on Oman's fisheries sector, which includes both artisanal and commercial fisheries. It examines maximum sustainable yield, economic sustainable yield, maximum carrying capacity, and economic rent for Oman's six coastal states. The analyses indicate overfishing in the Albatinah and Dhofar states, as their actual catch and number of vessels exceed the estimated MSY and ESY values. The other states show normal fishing levels.
Pelicice et al (ff in press) large reservoirs as barriers (1)Victor Ha-Kã Azevedo
This document discusses how large reservoirs create ecological barriers to downstream fish migration in South America in three key ways:
1. Reservoirs create a gradient of hydrological and limnological conditions between upstream and downstream reaches that acts as a behavioral barrier, as migratory fish are adapted to river environments and lack orientation across large standing water bodies.
2. The lack of flow in reservoirs prevents downstream drift of eggs and larvae passively transported to nursery habitats, with negative consequences.
3. In contrast to dams which block upstream movement, reservoirs specifically impede downstream movement of adults and young fish but do not strongly block upstream movement. No technical solutions exist to overcome the barrier posed by reservoirs.
3.Environmental variability at a marine cage culture.pdfearambulm3
This document summarizes an environmental study of a marine cage fish farm in Matanchén Bay, Mexico. Water and sediment samples were collected monthly from stations near the fish cages, upstream as controls, and downstream as potential impact areas. Physicochemical parameters of the water and sediment were analyzed, including nutrients, organic matter, and granulometry. Results showed temporal variations in nutrients in the water column and sediment composition. Nitrates generally had the highest concentrations in potential impact stations. Overall, parameters tended to increase in concentration in potential impact and control stations, indicating effects from the fish farm and seasonal runoff.
This document discusses how altering incentives, whether economic or social norms, can achieve positive outcomes for ocean sustainability. It provides examples of how well-designed rights-based fisheries and ecosystem service accounting have shifted economic incentives to align conservation and economic benefits. Modifying social norms can also incentivize sustainable practices by enhancing reputation or self-image. Recent successes in fishery reforms, marine spatial planning, and large marine reserves demonstrate that changing the feedbacks between individual actors and system properties can trigger transitions to more virtuous cycles. The key is to evaluate conservation tools by their ability to align incentives of different actors with broader sustainability goals.
The document analyzes how wind-driven hydrodynamics influence the plankton community in a shallow coastal lake in Brazil. Canonical correspondence analysis was used to test if environmental variables like turbidity, suspended solids, and water level formed seasonal spatial gradients in response to wind. The analysis found that certain physical variables correlated with plankton distribution, though plankton responded less readily than physical factors. It indicates that wind patterns govern the spatial and temporal distribution of physical, chemical, and biological aspects in the lake.
The document discusses the importance of incorporating traditional ecological knowledge (TEK) into fishery management. TEK refers to the knowledge acquired by indigenous groups over many generations through contact with the local environment. It includes knowledge of relationships between plants, animals, landscapes, and timing of events. TEK is location-specific, dynamic, and based on oral tradition. Incorporating TEK can help fishery management learn from traditional coastal management systems and improve compliance. TEK also provides valuable insights into climate change impacts and can help communities adapt strategies for natural resource management and seasonal forecasting. The document argues that resilience in fishery management requires attention to both the biological systems and human systems, and encourages the use of TEK and other
1) The document evaluates the management effectiveness of the National Natural Park Rosario and San Bernardo Corals marine protected area in Colombia using biological, socioeconomic, and governance indicators.
2) Biological surveys found low coral cover and fish diversity/abundance both inside and outside the MPA, suggesting limited effectiveness of current management. The reefs also showed signs of degradation.
3) Socioeconomic and governance analyses revealed low incomes for local communities, few opportunities, weak governance, and overexploitation of resources inside the MPA. This reflected low adaptive capacity to comply with conservation rules.
Marine fish aquaculture, antibiotics and escaped fish: the elephant in the room SergioC29
This document summarizes the key points from a literature review on the links between climate change, antibiotic use in aquaculture, and escaped farmed fish. It finds that climate change is increasing the risk of escapes due to more intense storms. Escaped fish that were treated with antibiotics pose food safety risks if consumed. The review identifies prevention strategies like marine spatial planning, vaccination, and improved equipment to reduce escapes. Mitigation strategies after escapes occur, like recapture efforts, are often ineffective for medicated fish. Traceability and monitoring of fishery landings are important to track impacts. Overall, the review calls for a combination of prevention and mitigation strategies, with a focus on vaccination and spatial planning, to sustainably manage risks
RECOMMENDATIONS FOR ENVIRONMENTAL MONITORING AROUND DEEP-SEA MINING SITESiQHub
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2) Early modeling suggested plumes from mining may impact areas 100 km away, and this was used to design buffer zones, but most current information is theoretical or from small experiments.
3) International organizations like the ISA call for using best available scientific evidence, techniques, and practices to monitor environmental impacts, but definitions and applications continue to be discussed.
4) Monitoring key properties of plumes like particle size and distribution is important to understand impacts and restoration timelines.
This study examined the relationship between seagrass coverage and invertebrate abundance on the island of South Caicos. Researchers measured seagrass coverage using transects and quadrats at six sites and recorded observed invertebrate species. The data analysis found no significant correlations between seagrass density and invertebrate abundance. While previous studies found such correlations, the researchers believe methodological issues and environmental conditions affected their results. Further research with improved methods is needed to better understand these relationships and inform plans to remove seagrass beds.
Final Draft Determining the effects of freshwater releasesJonathan Valentine
This study examines the effects of freshwater releases from Lake Okeechobee on mollusk communities in the maritime environment outside the Caloosahatchee Estuary in Florida. Gastropod assemblages from dredge samples in areas at high and low risk of influence from freshwater releases were analyzed using live-dead fidelity and rank order abundance metrics. Preliminary results show a trend of increasing live-dead fidelity with greater distance from the estuary mouth, though the trend is not statistically significant. Further study is needed to better quantify potential impacts on mollusk communities from freshwater releases and address issues like urbanization and climate change on future water management practices.
This document describes mapping ecological facets across Australia by analyzing the key drivers of ecosystem formation - macroclimate, lithology, landform, and vegetation structural formations. 59 homogeneous bioclimatic regions were mapped based on clustering uncorrelated bioclimatic variables. Lithology and weathering intensity were derived from existing Geoscience Australia data. Landform was characterized through land surface form and topographic moisture potential indicators. Combining these ecosystem drivers with vegetation structural formations data resulted in a continental dataset of 369,439 unique ecological facets at 90m resolution. This ecological facets mapping provides insight into biophysical variation across Australian ecosystems.
This document discusses using traits-based approaches to understand fish community ecology. It begins by outlining threats to freshwater fishes like habitat loss and pollution. The author argues that traits-based ecology enhances understanding of ecological patterns and processes, provides opportunities for generalization, and links biodiversity and ecosystem function. Research on fish traits can explain where species live, how many coexist in an area, and how they respond to environmental change. The author presents on using traits to predict extinction risk of fishes and anticipate how communities will respond to environmental change. Body size correlates with extinction risk, with smaller-bodied fishes less vulnerable. Life histories have evolved trade-offs that enable coping with ecological challenges. Traits may indicate ecosystem implications
Factors Contributing to the Decline of the Anchovy Fisheries in Krueng Raya B...Zulhamsyah Imran
This document summarizes a study on factors contributing to the decline of anchovy fisheries in Krueng Raya Bay, Indonesia. The study found that anchovy production peaked at 2,072 tons in 1999 but declined sharply to 171 tons after the 2004 tsunami. While production fluctuated between 126-279 tons from 2006-2012, it remained well below pre-tsunami and predicted maximum sustainable yield levels. The decline is attributed to increasing fishing effort through more lift net boats, destructive fishing gears, and degradation of coral reefs and mangroves from pollution and other human impacts. The tsunami exacerbated the decline but other anthropogenic factors likely had a greater long-term impact on depleting the anchovy stocks.
The invasive species challenge in estuarine and coastal (2)chechiasp
The document discusses introduced aquatic species in coastal environments. It covers several topics:
1) Introduced species are those transported outside their native range by human activities, with invasive species causing economic or ecological harm. Coastal areas are particularly at risk due to shipping and other vectors.
2) Australia and New Zealand have taken proactive approaches to prevention, eradication, and control, based strongly on science. The US lacks centralized management and federal leadership.
3) Case studies of the invasive algae Caulerpa taxifolia and cordgrass Spartina alterniflora showed the importance of early detection and action for successful eradication when populations are small.
This document discusses the need for integrated ecosystem-based management in Chilean fisheries. Currently, fisheries management in Chile focuses on single species stock assessments and total allowable catches without considering trophic interactions or community structure. Some studies have highlighted impacts of fishing and predation on species interactions, but more work is needed to guide research towards an ecosystem approach to fisheries management. The document proposes developing ecological indicators from monitoring programs and surveys to measure impacts on the ecosystem and inform adaptive management decisions. An integrated ecosystem monitoring, evaluation and diagnostic approach is necessary for effective ecosystem-based fisheries management in Chile.
Science Forum Day 4 - Marie Badjeck - Adaptation research in fisheriesWorldFish
The document summarizes research on the potential impacts of climate change on fisheries production and adaptation strategies. It describes scenarios developed through expert elicitation in Senegal, Ghana, and Peru to understand possible futures for fisheries. The scenarios identified diversification, aquaculture development, and regional integration as important adaptation strategies. Modeling results projected a 3.4% increase in potential global fisheries production by 2050 under climate change, with some regional variations. Capacity building in scenario planning was recommended to aid fisheries management under uncertainty.
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
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Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
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Film vocab for eal 3 students: Australia the movie
Bentonicos traducir fin
1. Population dynamics of benthic shellfisheries in the north of Chile: the role of denso-dependent processes
and oceanographic forcing
Marcelo M. Rivadeneira1, 2
, Raúl Ulloa3
, Adolfo Vargas4,5
& Cristian Hudson5
1Centro de Estudios Avanzados en Zonas Áridas (CEAZA) & Facultad de Ciencias del Mar, Universidad
Católica del Norte, P.O. Box 117, Coquimbo, Chile
2Center for Advanced Studies in Ecology and Biodiversity (CASEB), Departamento de Ecología Pontificia
Universidad Católica de Chile, Alameda 340, Santiago, Chile
3Centro Regional de Investigación Pesquera, Instituto Nacional de Pesca, Dirección General de
Investigación Pesquera Pacifico Norte. Miguel Alemán sur Nº605, C.P. 85400, Guaymas, Sonora, México
4Centro de Investigación y Desarrollo de Profesionales Marinos Pacífico Ltda. Vivar 1218, Iquique, Chile
5Programa Magíster en Ciencias Aplicadas mención Biología Pesquera, Departamento Ciencias del Mar,
Universidad Arturo Prat, P.O. Box 121, Iquique, Chile
Abstract:
The need of establish sustainable fishing policies clashes against the incapability of many models to
integrate mechanistically, yet in a simple way, the role played by biological (i.e. endogenous) and physical
(i.e. exogenous, oceanographic) forcing in the regulation of population dynamics. In this work we evaluate
the importance of endogenous and exogenous factors in the regulation of population dynamic in 10 benthic
species commercially exploited by the fishing artisanal fleet along northern coast of Chile. The information
was gathered from annual time series of CPUE (captures per unit of effort) between 1998 and 2005. The
population growth rate (i.e. interannual changes in the CPUE) was modeled as an autoregressive lineal
process, evaluating the importance of first-order lags (1 year) of CPUE, and oceanographic factors (southern
oscillation index, sea surface temperature, and upwelling index). In all species, the best models included the
effect of both endogenous and exogenous factors, explaining a high percentage of the variance of the
population growth rate (in average 88 %). These results support the idea that the studied populations,
despite being under an exploitation regime, show a strong regulation seemingly produced by the combined
effect of intraspecific interactions and physical forcing molding the abundance during the early stages of the
species. Our results highlight the importance of these kinds of models as a powerful tool to evaluate the
processes underlying the regulation of natural populations.
Key words: artisanal fisheries, Pacific South America, autoregressive model, El Niño, coastal upwelling
2. Resumen
La necesidad de establecer medidas de manejo pesquero sustentable se ve entorpecida por la incapacidad
de muchos modelos de incorporar mecanísticamente, pero aún de manera simple, el rol desempeñado por
forzantes biológicos (i.e. endógenos) y físicos (i.e. exógenos u oceanográficos) en la regulación de las
dinámicas poblacionales. En este trabajo evaluamos la existencia de regulación poblacional en 10 especies
bentónicas explotadas comercialmente por la flota pesquera artesanal en el norte grande de Chile. La
información fue obtenida a partir de series de tiempo anuales de capturas por unidad de esfuerzo (CPUE)
entre 1998 y 2005. Las tasas de crecimiento poblacional (i.e. cambios interanuales en la CPUE) fueron
modeladas como un proceso autoregresivo lineal, evaluándose la importancia de retrasos de primer orden
(1 año) en las capturas por unidad de esfuerzo y de factores oceanográficos (índice de oscilación del sur,
temperatura superficial del mar, e índice de surgencia costera). En todas las especies se verificó que los
mejores modelos incorporaron efectos denso-dependientes endógenos y exógenos, los cuales explicaron un
alto porcentaje de la varianza (en promedio 88%) de la tasa de crecimiento poblacional. Estos resultados
apoyan la idea de que las poblaciones estudiadas, a pesar de estar sometidas a un régimen de explotación,
exhiben una fuerte regulación, la que aparentemente estaría dada por interacciones intra-específicas y
forzamientos físicos que moldearían ciclos de vida tempranos de las especies. Los resultados aquí
obtenidos subrayan la utilidad de este tipo de modelos como valiosa herramienta para evaluar los procesos
subyacentes a regulación de las poblaciones naturales.
Palabras clave: pesquería artesanal, Pacífico de Sudamérica, modelo autoregresivo, biológicEl Niño,
surgencia costera
Introducción
The collapse of many fisheries along the global ocean has emphasized the urgent need to unveil the latest
processes and mechanisms that govern the dynamics of temporary space populations. In this sense, the
explicit incorporation of environment in the evaluation of fisheries is to be considered as relevant end to
achieve this objective (Wiff & Quiñones 2004). There are numerous examples that demonstrate the strong
dependence of the pelagic fisheries of the oceanographic conditions prevailing (Mantua et al. 1997, Yáñez et
al. 2001, Mantua & Hare 2002). However, the direct application and success of the conclusions reached
toward management measures is still in its infancy (Yañez et al. 2001). The need to implement better
models that make it possible to understand the dynamic fishing has led to the implementation of numerous
analytical perspective that explicitly or implicitly considered the role of the environment (e.g. , models based
3. on individuals, models of energy acquisition, analysis age/size structured, neural networks). However, its
application and implementation requires the generation of new and complex biological information, which is
not feasible in most cases. The scenario is even more complex in the case of benthic species of Chile, where
the bulk of the recent research has focused on descriptions bio-fishing (Defeo & Castile 1998, Castilla &
Defeo 2001, Leiva & Castile 2001).
The management recommendations have been based, in the last few years, in the implementation of marine
protected areas or areas of co-management fisheries (Fernandez & Castile 2005), however, those
recommendations underpinning success in a limited knowledge of the dynamic spatio-temporal system.
Even more, the very few models of management applied to benthic species in northern Chile that consider
the environment in an explicit manner (The Field 2002, Ortiz & Wolff 2002a, b, c), are of purely local area
and are methodologically difficult to implement (Why?). In a temporal context, fluctuations in the fisheries
have been associated with variations oceanographic, operants to macro-spatial scales and low-frequency
(Mantua et al. 1997, Chavez et al. 1999, Yáñez et al. 2001, Mantua & Hare 2002, Yáñez et al. 2002). In
most cases however, the fishing environmental analysis has been carried out mostly with a
phenomenological philosophy, for example leaving in evidence the importance of the sea surface
temperature (Freon & Yanez 1995) or of the turbulence (Yañez et al. 2001) In the interannual variations in
the catch of pelagic resources. However, this perspective does not account for the processes and/or
regulatory mechanisms that subyacerian to this correlation. Prospects more refined models based on
deterministic or stochastic majority have considered the role of endogenous factors (density-dependence),
but not of the environmental conditions in the population regulation (wiff & Quiñones 2004). The explicit
incorporation of endogenous and exogenous factors (environmental conditions) as determinants of
population dynamics has been developed widely in the environmental field in the last few decades (Lima et
al. 2001, Lima et al. 2002, Stenseth et al. 2002, Stenseth et al. 2003). Basically it states that the temporal
variations (e.g. , inter-annual) of the stocks would emerge as part of an internal dynamic, in which the built-in
bias toward the populations to expand (i.e. exponential growth) would be offset by density-dependent
processes (e.g. , intraspecific competition, competition inter-specific, predation).
In this framework, the role of environmental forcings (e.g. , the Child, transport offshore) would be made a
manifest through the dense structure-dependence on the population, and could be modeled explicitly, in
linear terms or non-linear (Stenseth et al. 2002). The action of both mechanisms and its time lag would be
causing the populations to vary in the time (short and/or medium-term), although in the long term, the
4. abundance of the population is stationary (do permanently stationary or determined by the load capacity of
the environment, which may also have different levels? ). Then, the existence of natural cycles in the
abundance of populations, evident also in benthic species, that could and should be considered explicitly in
the fisheries management plans. In the present study raises the explicit use of this approach of analysis is to
allow glimpse possible processes and mechanisms that govern temporary fluctuations in benthic fisheries in
the north of Chile.
In particular, it evaluates the adjustment autoregressive models that consider endogenous and exogenous
effects on the population dynamics of 10 species. This step would be key in the generation of effective
management measures for these resources.
Material y métodos
Obtaining time series of CPUE: information was obtained from a database of the follow-up project of
benthic fisheries executed by the Fisheries Development Institute of Chile (FIFG), where are documented
catches (kg) for various benthic resources in a total of 231 sites (backgrounds) distributed from Africa to the
south of Antofagasta (ca.18 ° -25 °S), covering an area of ca. 800 Km of coastline, between the years 1998-
2005. In order to obtain a synoptic view, chose to ignore trends space as well as temporal trends intra-
annual, by expressing the total annual catch as for each resource. As a measure of fishing effort is used the
number of trips made to that origin for that resource and year. Of the total of 30 species recorded only
analysis was performed with 10 of them, since they correspond to the 98% of this information (Table 1).
Obtaining of oceanographic information: synoptic oceanographic information was obtained in the form of
annual averages for the entire region considering the period 1998-2005. Three oceanographic variables
were analyzed: sea surface temperature (SST), index of Southern Oscillation (SOI), and index of upwelling
(UPW). It generated an average annual regional TSM using the information obtained for three main ports
(Arica, Iquique, Antofagasta) using in-situ measurements (CENDOHC-SHOA). The average annual value of
SOI and UPW (transport offshore Ekman) was obtained from time series available at NOAA, and were
recovered in your web site (http://www.pfeg.noaa.gov:16080/products/PFEL/) finally these values were
obtained by averaging the values of 3 stations that are available for each fishing site in the region of study.
5. Analysis of population dynamics: We evaluated the population dynamics at the regional level of each of the
species, by modeling the time series of population growth rates (Lima 2001, Stenseth et al. 2002, Belgrano
et al. 2004B):
Where: it is the intrinsic rate of population growth in the t year, y, and corresponds to the CPUE in the t and
the previous year, respectively.
If this is a feature that gives an account of the relationship between y and , and the delays, then:
Where: It is a linear relationship of dependency between and the delays of abundance.
Due to the short length of the time series (8 years) were evaluated only dynamic of first order (delay for 1
year). In this way, in his simpler version (linear) population dynamics could be modeled on the basis of:
Where:
y are parameter to find the estimate of y
Where: ENV is from any of the oceanographic variables evaluated (TSM, SOI, and UPW).
The choice of the best models was carried out using the Akaike Information Criterion (AIC), where all the
models with a ∆AIC<2 and AIC weighted>0.2 , were considered equally probable. All analysis were carried
out using routines written in the program R (Team 2008).
Results
The populations studied showed different temporal dynamics (Fig 2). The cholga mussel, crab and the hairy
octopus fluctuations showed relatively small populations during the period of analysis. Species such as the
locate and the choro showed sharp increases in the CPUE, whereas the piure, culengue showed drops and
clam population. Other species exhibited fluctuations with more marking, such as the scarlet macaw black,
whose abundance ranged over 2 orders of magnitude in the study. Of the total of 11 models evaluated for
each species (110 in total), only 1-2 were selected in each case (Table 2). The selected models in general
6. accounted for much of the variance of the population growth (R² average =0.88 [0.46 , 0.99 ], Table 2), so
that the population dynamics of these species was generally well captured by such models (Fig 2). All the
models selected incorporated at the same time effects density-dependent and at least one variable
oceanographic. More than half of the selected models (8 of 15) incorporated delays of first order in the CPUE
and the three variables studied oceanographic. The sign and intensity of the coefficients auto-regressive
associated was variable between species. While the ratio of density-dependence was always negative, the
coefficients associated with the TSM, SOI, and UPW were positive or negative.
Discusión
The results confirm the existence of a marked population regulation in the 10 species of benthic
analysis. This regulation would emerge from the joint action of density-dependent processes and
oceanographic forcing through the feedback of population structure. Traditionally it has been
argued that the oceanographic forcing would have a leading role in fluctuations in abundance of
fisheries (Yañez et al. 2001, Yáñez et al. 2002, Lehodey et al. 2006, Friedemann & Wolff 2008).
However, oceanographic modeling of radiative forcing to the interior structure of the density-
dependent is somewhat recent (Belgrano et al. 2004A, 2004b, Pedraza-Garc ia & Cubillos 2008).
The results give evidence that there are endogenous and exogenous mechanisms that regulate the
overall dynamics of the populations studied. On the one hand, the existence of an endogenous
regulation density-dependent is evident by the negative sign of the coefficients of density-
dependence, α, of all the autoregressive models (Table 2), suggesting that feedback processes of
population of first order would be key in the population dynamics.
. In this sense, a large number of empirical studies validated the importance of larval settlement and
recruitment as a determinant of the structure of populations and marine communities on the coast of
Chile (Lakes et al. 2005, Navarrete et al. 2005). However, it cannot be ruled out a priori in the
existence of delays of higher order ( Pedraza-Garc ia & Cubillos 2008), which would reflect inter-
specific processes (e.g. competition and predation) whose relevance as mechanisms of population
regulation is suggested by empirical evidence (Castile 1999, Gaymer et al. 2004, Vásquez et al.
7. 2006, Gaymer & Himmelman 2008, Navarrete & Manzur 2008). Time Series of greater extension
(> 10 years) would make possible the implementation of these models. On the other hand, these
processes of feedback also would be forced by exogenous factors (i.e. , oceanography) that would
work together by regulating populations, as has been observed in species of marine phytoplankton
(Belgrano et al. 2004A, 2004b).
Experimental studies show that the structure and dynamics of populations and marine communities
in the southeastern coast of the Pacific is heavily governed by stressors of low frequency as El
Niño(Chavez et al. 1999, Thiel et al. 2007) As well as by the larval dispersal patterns generated by
the cells of coastal upwelling (Lakes et al. 2005, Navarrete et al. 2005, Lakes et al. 2008). However
the population effects of these factors track structure density-dependent only have been evident in
the present study. The underlying mechanisms are much less well known, but it is possible that
factors such as SOI indirectly affect recruitment rates of the species, track changes in the intensity
of the transport offshore (Connolly & Roughgarden 1999), or changes in vital rates induced by the
temperature of the sea (Urban 1994, Wolff et al. 2007). However, the direction and intensity of the
coefficients associated with each variable oceanographic was highly variable between species,
which is not strange as there is empirical evidence that indicates that the responses of marine
populations to ENSO events would be species-specific (Díaz & System 1993). The foregoing
suggests that ecological features and/or the history of life could also play a predominant role in
population dynamics. Time series analysis more extensive and the explicit inclusion of the space
(e.g. , analyzing the spatial synchrony of population dynamics) in species with different life
strategies could shed more light on the mechanisms that govern the different population responses
to oceanographic forcing.
The present study demonstrated the feasibility of applying simple autoregressive models for
understanding the role of biological interactions and oceanographic stressors in the regulation of
8. marine populations. Similar models or more complex (i.e. , non-linear, second-order delays,
explicitly including interactions predator-prey, Pedraza-Garc ia & Cubillos 2008) could be applied
to other stocks for which there are estimates of relative abundance of species. The results obtained
by these simple models could serve as a basis for the development of more sophisticated models
with a view to a sustainable management of marine ecosystems.
9. Table 1. Main characteristics of the species in this study. Status of holdings according to SubPesca
(PE: full exploitation, THE: free access, LAC: free access to administrative restrictions).
Table 1. Main characteristics of the species this study. The exploitation status according SubPesca
Chile (PE: fully exploited, THE: open access, LAC: open access with administrative restrictions).
Fig 2. Population Dynamics of 10 marine species commercially extracted by the artisanal fishing
fleet between 1998-2005. The expected values were estimated using the parameters of the
autoregressive model with the best fit for each species (see Table 2).
Fig 2. Population dynamics of 10 marine species exploited by artisanal shellfisheries between
1998-2005. The expected values were estimated using the parameters yielded by the best
autoregressive model for each species (see Table 2).
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14. Tabla 1. Principales características de las especies de este estudio. Estatus de explotación de acuerdo a SubPesca (PE: plena explotación, LA: libre acceso, LAC:
libre acceso con restricciones administrativas).
Table 1. Main characteristics of the species this study. The exploitation status according SubPesca Chile (PE: fully exploited, LA: open access, LAC: open access
with administrative restrictions).
CPUE (kg
viaje-1
)
N° de procedencias por año
Taxa Nombre científico Nombre
común
Estatus de
explotació
n
Promedio Promedio Mínimo Máximo
Gastropoda Thais chocolata (Duclos, 1832) Caracol
locate
LAC 390 73 52 90
Echinoidea Loxechinus albus (Molina, 1782) Erizo PE 228 77 28 126
Bivalvia Aulacomya atra (Molina, 1782) Cholga PE 208 63 45 71
Tunicata Pyura chilensis Molina, 1782 Piure LA 199 65 31 83
Bivalvia Gari solida (Gray, 1828) Culengue PE 76 25 5 47
Bivalvia Protothaca thaca (Molina, 1782) Almeja PE 70 52 40 69
Bivalvia Mytilus chilensis (Hupé 1854) Choro PE 62 16 11 23
Decapoda Cancer setosus Fabricius, 1798 Jaiba peluda LAC 54 58 14 74
Gastropoda Fissurella latimarginata Lesson,
1831
Lapa negra PE 51 25 7 51
Cephalopoda Octopus mimus Gould, 1852 Pulpo PE 45 130 84 154
15. Tabla 2. Evaluación de los 11 Modelos auto-regresivos de primer orden de análisis de las dinámicas poblacionales de cada especie (retraso de 1 año en la señal).
Table 2. Summary if the autoregressive models used to analyze the population dynamics of each species. 11 first-order autoregressive models (1 year lag) were
evaluated.
Coeficientes de regresión
Especie Modelo AIC ∆AIC AICp R² P
Almeja -13,77 0,00 0,519 0,969 0,009 -4,183 -1,194 0,058 0,525
-13,61 0,16 0,479 0,976 0,047 -3,409 -1,241 0,057 0,495 -0,001
Caracol
locate
-4,83 0,00 0,316 0,686 0,099 2,944 -0,489 -0,028
-3,91 0,92 0,200 0,731 0,217 4,109 -0,443 -0,031 -0,082
Cholga -38,97 0,00 1,000 0,997 0,007 3,309 -1,466 0,038 0,245 0,006
Choro -3,88 0,00 0,868 0,953 0,091 15,036 -1,110 -0,132 -0,588 -0,007
Culengue 10,09 0,00 0,522 0,824 0,321 -14,928 -2,099 0,182 1,316 0,026
Erizo -5,36 0,00 0,379 0,458 0,554 14,486 -0,460 -0,675 -0,005
-4,66 0,69 0,268 0,451 0,302 14,425 -0,631 -0,627
Jaiba peluda -12,34 0,00 0,605 0,976 0,047 4,428 -1,130 -0,017 0,004
-10,35 1,99 0,223 0,953 0,093 4,563 -1,137 -0,018 -0,006 0,004
Lapa negra 3,65 0,00 0,988 0,979 0,043 28,828 -2,315 -0,077 -1,249 0,052
Piure -25,92 0,00 0,998 0,994 0,011 -2,567 -0,829 0,057 0,388 0,004
Pulpo -14,05 0,00 0,577 0,968 0,062 0,463 -1,776 0,010 0,362 -0,005
-13,24 0,81 0,385 0,953 0,017 1,542 -1,565 0,256 -0,005
16. Fig. 1. Mapa del área de estudio en el norte grande de Chile, mostrando la localización
geográfica de las 231 áreas de pesca en el área de estudio (cuadrados claros).
Fig. 1. Map of the study area at the northern Chile region, showing the geographic location of
the 231 fishing localities used in this study (empty squares).
17. Fig. 2. Dinámica poblacional de 10 especies marinas extraídas comercialmente por la flota
pesquera artesanal entre 1998-2005. Los valores esperados se estimaron usando los
parámetros del modelo autoregresivo con el mejor ajuste para cada especie (ver Tabla 2).
Fig. 2. Population dynamics of 10 marine species exploited by artisanal shellfisheries between
1998-2005. The expected values were estimated using the parameters yielded by the best
autoregressive model for each species (see Table 2).