This document discusses the age and growth of the red toothed triggerfish (Odonus niger) off the coast of Thoothukudi, India. It analyzed samples collected from bottom trawls between 2008° 53.6'N latitude 78° 16'E longitude and 08° 53.8'N latitude 78° 32'E longitude. The von Bertalanffy growth parameters were estimated as L∞ = 283.90 cm and K = 0.75. Total mortality was estimated to be 1.07 and fishing mortality was 0.27. The exploitation ratio was estimated to be 0.25, indicating the stock is under fishing pressure. The estimated life span of O. niger appears to
METHODOLOGICAL SUPPORT FOR EXPLORING THE LFI: “PROPORTION OF LARGE FISH - INDICATOR” PROPERTIES FOR INTERPRETING THE CHANGES IN THE FISH COMMUNITY OF THE SOUTH ADRIATIC AREA (GSA18)
Legislative Priorities of the Alaska Native Health BoardCharles Clement
A resident of Juneau, Alaska, Charles Clement participates in various community projects. Professionally, he currently serves as the president of the South East Alaska Regional Health Consortium, or SEARHC. Charles Clement also serves on the Alaska Native Health Board (ANHB).
METHODOLOGICAL SUPPORT FOR EXPLORING THE LFI: “PROPORTION OF LARGE FISH - INDICATOR” PROPERTIES FOR INTERPRETING THE CHANGES IN THE FISH COMMUNITY OF THE SOUTH ADRIATIC AREA (GSA18)
Legislative Priorities of the Alaska Native Health BoardCharles Clement
A resident of Juneau, Alaska, Charles Clement participates in various community projects. Professionally, he currently serves as the president of the South East Alaska Regional Health Consortium, or SEARHC. Charles Clement also serves on the Alaska Native Health Board (ANHB).
Bulb Biology, The Paperwhite Narcissus Flower Project And Hyacinth HydroponicsMary Van Dyke
This is a link to a 7-minute film on bulb biology, a lesson plan for planting a paperwhite narcissus bulb to grow to flower at home or in the classroom, and how to grow a hyacinth flower hydroponically in a vase or jar. Enjoy indoor winter gardening! For elementary 3 - 5.
Zur Klosterpolitik Kurfürst Friedrichs des Siegreichen und seiner VorgängerJoachim Kemper
Joachim Kemper: Zur Klosterpolitik Kurfürst Friedrichs des Siegreichen
und seiner Vorgänger.
Per brachii saecularis auxilium?
In: Friedrich der Siegreiche
(1425–1476)
Beiträge zur Erforschung eines
spätmittelalterlichen Landesfürsten. Neustadt an der Weinstraße 2016. S. 271-279
Size distribution and biometric relationships of little tunny Euthynnus allet...inventy
This study is taken from data of commercial fishing of the little tunny, Euthynnus alletteratus (Rafinesque, 1810) caught in the Algerian coast, sampled between november 2011 and april 2016. Data were collected in order to determine size distributions of the population and biometric relationships of species including the size - weight relationships. A total of 601 fish ranged from 30.9 and 103 cm fork length (FL) were observed. The size distribution of Euthynnus alletteratus shows multiple modal values witch the most important cohort corresponds to the age class 2 (42-46 cm). The value of the allometric coefficient (b) of the FL/TW relationship is lower than 3, indicating a negative allometric growth.
This study is an attempt to understand the population characteristics such as Length-weight relationships, age, growth, mortality, length at age and exploitation rate of Frigate tuna, Auxis thazard occurring in the North west coast of India. The data collected from various fish landing centers from 2008 to 2012 were considered for this study. The mean fork length and weight 32.35 cm and 1.040 kg were observed respectively. The length-weight relationship W=2.4321x10-1 FL 2.27658, and r2 0.9576 was obtained. The value of ‘b’ found to be less than 3 and hence this species is showing negative allometric growth. The growth parameters on von Bertalanffy for L∞ estimated as 47.03, K was 1.30 and to was -0.23. The Phi-prime value (⏀) of 3.33 was derived. The length at age observed at the end of 1 to 4 years was 27.0, 42.0, 50.0 and 55.0 cm year-1 respectively. The natural mortality (M) 1.00 year-1, total mortality (Z) of 4.43 year-1 and fishing mortality (F) 3.43 year-1 were derived with the mean temperature of 27°C. The exploitation ratio(E) and exploitation rate(U) was 0.77. The results derived in the present study with regard to population characteristics of frigate tuna in the coastal waters of North west coast of India indicate catching of this species in the area to be minimized Key-words- Length-weight relationships, Mortality, Length at age, Exploitation ratio, Exploitation rate
Population characteristics of the Japanese threadfin bream Nemipterus japonic...AbdullaAlAsif1
Nemipterus japonicus (Japanese threadfin bream) is one of the most significant fish species throughout the Indo-Pacific regions. No previous studies on the population dynamics of N. japonicus have been carried out in the Eastern Malaysia (Malaysian Borneo). The present study focused on the population dynamics of N. japonicus from April 2013 to March 2014 in the coastal area of Bintulu, South China Sea. Local fishermen provided samples, which were then analysed. The FiSAT II software was used to evaluate the collected length frequency data. The asymptotic length (L ∞) and growth coefficient (K) were 26.78 cm and 0.85 yr-1, respectively. The growth performance index (ϕ'), total mortality coefficient (Z), natural mortality (M) and fishing mortality (F) were 2.785, 2.97, 1.63 and 1.34 per year, respectively. According to the estimates, the exploitation rate (E) for N. japonicus was 0.45, while the E 0.1 , E 0.5 and E max were determined as 0.72, 0.4 and 0.806, respectively. The obtained value of exploitation was less than E max, although slightly higher than E 0.5. The recruitment characteristics of N. japonicus have been stable throughout the year, with one peak pulse. The results contribute to the knowledge of the dynamics of N. japonicus populations and are important for the sustainable management of the Sarawak fishing resources.
Accretion Profile of the Rosy Barb, Puntius Conchonius (Hamilton- Buchanan, 1...IOSR Journals
Present study was made on 50 freshwater wild Puntius conchonius (Hamilton - Buchanan) of
various sizes ranging from a total length of 5.2 cm to 7.6 cm and weighing 1.6 gm to 7.1 gm. They were
sampled from different lentic and lotic water bodies of Nagaland, to investigate the weight-length relationship.
Each fish was measured and weight was taken. Log transformed regressions were used to test the growth trend. It was observed that growth in weight is not proportional to the cube of its length. Coefficient of correlation values for both male and female as well as for mixed population were found to be highly significant.
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.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Bulb Biology, The Paperwhite Narcissus Flower Project And Hyacinth HydroponicsMary Van Dyke
This is a link to a 7-minute film on bulb biology, a lesson plan for planting a paperwhite narcissus bulb to grow to flower at home or in the classroom, and how to grow a hyacinth flower hydroponically in a vase or jar. Enjoy indoor winter gardening! For elementary 3 - 5.
Zur Klosterpolitik Kurfürst Friedrichs des Siegreichen und seiner VorgängerJoachim Kemper
Joachim Kemper: Zur Klosterpolitik Kurfürst Friedrichs des Siegreichen
und seiner Vorgänger.
Per brachii saecularis auxilium?
In: Friedrich der Siegreiche
(1425–1476)
Beiträge zur Erforschung eines
spätmittelalterlichen Landesfürsten. Neustadt an der Weinstraße 2016. S. 271-279
Size distribution and biometric relationships of little tunny Euthynnus allet...inventy
This study is taken from data of commercial fishing of the little tunny, Euthynnus alletteratus (Rafinesque, 1810) caught in the Algerian coast, sampled between november 2011 and april 2016. Data were collected in order to determine size distributions of the population and biometric relationships of species including the size - weight relationships. A total of 601 fish ranged from 30.9 and 103 cm fork length (FL) were observed. The size distribution of Euthynnus alletteratus shows multiple modal values witch the most important cohort corresponds to the age class 2 (42-46 cm). The value of the allometric coefficient (b) of the FL/TW relationship is lower than 3, indicating a negative allometric growth.
This study is an attempt to understand the population characteristics such as Length-weight relationships, age, growth, mortality, length at age and exploitation rate of Frigate tuna, Auxis thazard occurring in the North west coast of India. The data collected from various fish landing centers from 2008 to 2012 were considered for this study. The mean fork length and weight 32.35 cm and 1.040 kg were observed respectively. The length-weight relationship W=2.4321x10-1 FL 2.27658, and r2 0.9576 was obtained. The value of ‘b’ found to be less than 3 and hence this species is showing negative allometric growth. The growth parameters on von Bertalanffy for L∞ estimated as 47.03, K was 1.30 and to was -0.23. The Phi-prime value (⏀) of 3.33 was derived. The length at age observed at the end of 1 to 4 years was 27.0, 42.0, 50.0 and 55.0 cm year-1 respectively. The natural mortality (M) 1.00 year-1, total mortality (Z) of 4.43 year-1 and fishing mortality (F) 3.43 year-1 were derived with the mean temperature of 27°C. The exploitation ratio(E) and exploitation rate(U) was 0.77. The results derived in the present study with regard to population characteristics of frigate tuna in the coastal waters of North west coast of India indicate catching of this species in the area to be minimized Key-words- Length-weight relationships, Mortality, Length at age, Exploitation ratio, Exploitation rate
Population characteristics of the Japanese threadfin bream Nemipterus japonic...AbdullaAlAsif1
Nemipterus japonicus (Japanese threadfin bream) is one of the most significant fish species throughout the Indo-Pacific regions. No previous studies on the population dynamics of N. japonicus have been carried out in the Eastern Malaysia (Malaysian Borneo). The present study focused on the population dynamics of N. japonicus from April 2013 to March 2014 in the coastal area of Bintulu, South China Sea. Local fishermen provided samples, which were then analysed. The FiSAT II software was used to evaluate the collected length frequency data. The asymptotic length (L ∞) and growth coefficient (K) were 26.78 cm and 0.85 yr-1, respectively. The growth performance index (ϕ'), total mortality coefficient (Z), natural mortality (M) and fishing mortality (F) were 2.785, 2.97, 1.63 and 1.34 per year, respectively. According to the estimates, the exploitation rate (E) for N. japonicus was 0.45, while the E 0.1 , E 0.5 and E max were determined as 0.72, 0.4 and 0.806, respectively. The obtained value of exploitation was less than E max, although slightly higher than E 0.5. The recruitment characteristics of N. japonicus have been stable throughout the year, with one peak pulse. The results contribute to the knowledge of the dynamics of N. japonicus populations and are important for the sustainable management of the Sarawak fishing resources.
Accretion Profile of the Rosy Barb, Puntius Conchonius (Hamilton- Buchanan, 1...IOSR Journals
Present study was made on 50 freshwater wild Puntius conchonius (Hamilton - Buchanan) of
various sizes ranging from a total length of 5.2 cm to 7.6 cm and weighing 1.6 gm to 7.1 gm. They were
sampled from different lentic and lotic water bodies of Nagaland, to investigate the weight-length relationship.
Each fish was measured and weight was taken. Log transformed regressions were used to test the growth trend. It was observed that growth in weight is not proportional to the cube of its length. Coefficient of correlation values for both male and female as well as for mixed population were found to be highly significant.
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.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Length-Weight Relaonships (LWR) were calculated for 22 commercial fish species caught by the arsanal fishing fleet of Margarita Island, Venezuela. A total of 1,610 specimens were analysed, distributed in the following species: Lagocephalus
laevigatus, Sphyraena guachancho, S. barracuda, Lutjanus purpureus, L. analis, L. griseus, Rhomboplites aurorubens, Lachnolaimus maximus, Priacanthus arenatus, Scomberomorus cavalla, S. brasiliensis, Euthynnus alleeratus, Auxis thazard, Sarda
sarda, Thunnus atlan!cus, Rachycentron canadum, Caranx hippos, C. crysos, Selene setapinnis, Alec!s ciliaris, Trachinotus carolinus and Elops saurus. These length-weight
relaonships can be used to improve fish stascs because of difficulty in obtaining weight of the fish in field.
Length Frequency Distribution, Length-Weight Relationship and Condition Facto...paperpublications3
Abstract: Length –Frequency Distribution, Length – Weight relationship and condition factor of Pomadasys jubelini from the Lagos lagoon were investigated for 6months in order to study the growth pattern and wellbeing of P.jubelini. A total of 305 specimens of P.jubelini were purchased from local fisher-folks on landing sites at different locations within the Lagos lagoon ( Majidun, Makoko, Ibese, Bayeiku) from January 2012 to June 2012 and used for this study. Their Total length ranging from 12cm to 29.5cm and body weight ranged from 21.3g to 367g. The frequency distribution showed a polymodal distribution of P.jubelini. The size class of 18.0cm to 20.9cm (TL) was more abundant. The length weight relationship was determined by regression coefficient equation Log W= -1.8357+2.9628LogL (n =305, r = 0.9213). P.jubelini showed negative allometric growth (b= 2.96). The mean condition factor 1.31, indicates that P.jubelini were in good condition in the lagoon. The result from this study is relevant for fishery management and stock assessment studies of P.jubelini from the Lagos lagoon.
Recruitment, mortality and exploitation rates estimate and stock assessment o...sarmodou
SARR Serigne Modou1,
*KABRE Tinkoudgou Jean-André1 and CECCHI Philippe2
1 Laboratoire de Recherche et de Formation en Pêche et Faune (LaRFPF/ IDR), Université de Bobo-Dioulasso, BP. 1091 Bobo 01, Burkina Faso.
2 Institut de Recherche et Développement (France).
*Corresponding author.
E-mail: ankab226@yahoo.fr
Tel: +22670231734.
The overfishing is the central problem of the Mugil cephalus fisheries in the estuary of the Senegal River. This species lives in the sea during its adult stage but returns in the Senegal River to reproduce and to spend its larval and juvenile stages. This study is aimed to pinpoint the state of exploitation dynamic and to assess the M. cephalus stock. The FISAT II software was used to perform the estimate of recruitment, mortality and exploitation rates. Meanwhile, a virtual population analysis using VIT4 software estimated yield per recruit (Y/R). The analysis yielded exploitation rates E of 0.44 and 0.23 respectively for adult fish and juveniles; therefore the adult stock is overfished during the M. cephalus life stage in sea. In addition, natural mortality (M=1.20 year-1) and total mortality (Z=1.5 year-1) are remarkably high for fish mature age groups III, IV and V. However, in the river the maximum sustainable exploitation (0.50) is not exceeded for juveniles age groups 0+, I and II. In conclusion, management policies should be introduced to safeguard the M. cephalus fishery in the estuary of the Senegal River.
Population Dynamics of the Annular Seabream Diplodus annularis (Linnaeus, 197...Premier Publishers
Age, growth, length-weight relationship (LWR), condition factor (K) and relative condition factor (Kn) were investigated for the annular seabream Diplodus annularis collected from non-commercial catches around the Maltese Islands between July 2012 and December 2017 (N=1661). The age distribution of the specimens was found to range between 0+ and 17+ years with a positive allometric growth. Average Kn was found to be 1.03 in males and 0.99 in females. The growth parameters of the von Bertalanffy equation were: L∞=21.38, K=0.123year-1 and tₒ = -5.40year for all individuals (males, females, hermaphrodites and unsexed). This study is the first reference for D. annularis on the length weight equation parameters, condition factor, relative condition factor and age around the Maltese Islands and establishes a new maximum of 17 years.
Similar to 2015 c-Age and Growth of Odonus niger-May-2-5-204-209 (20)
2.
~ 205 ~
International Journal of Fisheries and Aquatic Studies
fishing mortality (F), total mortality (Z), exploitation ratio (E) and recruitment pattern
(Lc/L∞); where Lc is length at first capture) and M/K and
length-weight relationship of O. niger off Thoothukudi coast
of Gulf of Mannar, southeast coast of India.
2. Materials and Methods
Samples of Odonus niger (Family: Balistidae) were collected
from bottom trawl, Off Thoothukudi fishing harbour, southeast
coast of India. Its distribution was recorded up to 36 m depth
between 08° 53.6’N lat. 78° 16’E long and 08° 53.8’N lat. 78°
32’E long, 38 miles from Thoothukudi fishing harbour,
southeast coast of India. The total-length was measured from
(range: 8 to 31.5 cm) the tip of the snout to the tip of the upper
lobe of caudal-fin mm and weight was recorded to the nearest
0.1 gm. The Specimen where the tails are broken is rejected.
The von Bertalanffy growth parameters, namely, L∞ and K
were estimated by length frequency (in discrete series)
analysis using computer program ELEFAN I as suggested by
[6, 7, 23, 35]
.
The natural mortality (M) was estimated using the empirical
relationship derived by [25]
as follows:
Log 10 M = -0.0066-0.279 Log 10 L∞ +0.6543 Log 10 K+
0.4634 Log 10 T
Where, L is expressed in cm and T (28ºC) is the mean annual
environmental temperature. The t0 was estimated following
the empirical formula derived by [24]
as given below:
Log 10 (-t0) = -0.3922-0.2752 log 10 L∞ -1.038 log 10 K.
The total mortality (Z) was estimated by the length-converted
catch curve method [26]
. Fishing mortality (F) was estimated by
subtracting M from Z and exploitation rate (E) from E = F/Z8
.
Relative yield-per-recruit (Y/R) was obtained from the
estimated growth parameter and probability of capture by
length27
. All other calculations were made using ELEFAN
program developed by ICLARM. Length-weight relationship
was estimated by least square method using the formula of W
= aLb
.
3. Results and Discussion
In general, small to medium sized fish are characterized by fast
growth, shorter life span, young age-at-maturity, and serial
spawning periodicity, which are characteristic of r-selected
species. As a result, these species are able to display faster
turnover rates. On the other hand, K-selected species display
slower growth, older age-at-maturity, large size, longer life-
span, and infrequent spawning periodicity. The conservative
life history characteristics of these species make them more
vulnerable to overfishing.
3.1 Growth parameters
Fig.1 shows restructured length distribution for the computed
growth curve. The von Bertalanffy growth equation for
Odonus niger was estimated as L∞ = 283.90 and K= 0.75.
However, some species such as the grey triggerfish (Balistes
capriscus) growth parameters obtained from all back-
calculation including end-points (derived data) of Balistes
capriscus were L∞ = 485.88±19.17 mm and K = 0.22 (1/year)
and Balistes punctatus were L∞ = 275.76±3.38 mm and K =
0.48 (1/year) [21, 22]
. The present species is relatively moderate
in growth K = 0.75. According to [39]
fishes with moderate K
are characteristic with moderate natural mortality, and it is
related to age and size of the fish. The M value is 0.80 and the
M/K ratio of O. niger was 1.06. The estimated life span
appears to be 2.5 years (Fig 8). The M/K ration is found to be
in close proximity limit among the closely related species [3]
.
The M/K ration is fishes generally falls within the range of 2.0
– 3.0. The von Bertalanffy parameters K and L∞ can be
plotted to provide summaries of growth performance in variety
of taxa [28]
. has presented such a summary based on 4826 sets
of parameter estimates of the von Bertalanffy growth function.
This generated the familiar negative relationship, confirming
the conclusion of [28]
that fishes either tend to remain small and
have high K values or become large or have low K values.
Thus although the parameters K and L∞ allow comparison of
growth patterns they do not capture the important life history
features that arise from differences in life-span.
The total mortality (Z) and fishing mortality (F) were 1.07 and
0.27, respectively. Fig.2 represents the catch curve constructed
for estimation of Z. The darkened quadrilateral represents the
points used for estimating Z through least square. The open
circles represent points either not fully recruited of nearing L∞
or hence not considered for calculation. Good fit to the
descending right hand limits of the catch curve was
considered.
Considering fishing (F), natural (M) and total (Z) mortalities
of a fisheries resource which is collapsed, for instance,
triggerfish resource in Thoothukudi coast of Gulf of Mannar,
southeast coast of India. Z is supposed to be the sum of M and
F, so at least for negligible F (since the fisheries had
collapsed), Z should have been equal to M. But in nature, 1 + 1
≠ 2 meaning that natural causes of mortality may be varying
from time to time to either increase or decrease M, and hence
the relation:
F + M = Z
When F = 0, or F ≈ 0 (in collapsed fisheries scenario) does not
necessarily imply the M = Z. Rather, either M ≤ Z, or M ≥ Z.
Bur M and Z can be very close in the case of collapsed
fisheries. M can also be was higher than Z since the derivation
of Z is independent of M (for instance), Z obtained from
length-converted catch model). This is because in collapsed
fisheries Z was obtained from sparse length-frequency data
due to absence of specimen.
In the present study deal with exploitation ratio (E) was
estimated 0.25. As the E is <0.5, it appears that the stock of O.
niger along southeast coast is under much fishing pressure.
The values of the asymptotic length (L∞) and the growth
coefficient (K) calculated from the Ford-Walford plot was L∞
= 283.90 cm and K = 0.75. The value of t0 calculated from the
plot L^ L∞ -Lj) = aj + b is: t0= -0.47 year. Total mortality (Z =
F + M) was estimated using the method of3
and natural
mortality (M) using Pauly's formula [24]
. The size at first
capture Lc observed is close to the calculated figure of 0.02
cm which gives maximum yields per recruit. According to [9]
,
if the E is >0.5 the stock may be considered as overfished.
3.2 Age and Growth
The size range of O. niger in the trawl fishery recorded was
8.0 to 31.5 cm. A preliminary estimate of asymptotic length
(L∞) was obtained by Powell and Wetherall (Was L∞ =
283.90 cm and K = 0.75. The month wise data on size
distribution of O. niger was collected during January 2011-
December 2012 and was utilized for the estimation of growth
parameters through ELEFAN I programme. A preliminary
estimate of K was obtained with an input of L∞ of 283.90 cm,
which gave the value of K as 0.75 (Fig 2). There have been
relatively few age and growth studies on Balistes capriscus;
however, they are estimated to live up to 11 years, with 16
being the maximum age recorded [9, 42, 10]
. Balistes capriscus
3.
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International Journal of Fisheries and Aquatic Studies
are estimated to grow rapidly within the first year of life (K =
0.39), then growth slows and is estimated at K = 0.152-0.183
year-1 for both sexes combined [9, 10, 42, 37]
. Balistes capriscus
spawn as early as May and as late as August, with peak
spawning in June and July in the Gulf of Mexico and South
Atlantic Bight [42, 9, 10, 17, 12, 38]
. Both sexes were reproductively
mature by age-2, 10 inches FL (250 mm FL). At this size (~10
inches FL), some males were age-1 and all females were [42, 10]
.
Average back-calculated lengths-at-age calculated as weighted
means were presented in [11]
as 11.3 cm, 23. 7 cm, 30.6 cm,
35.4 cm, and 39.3 cm for age 1, II, III, IV and V respectively.
1
gave estimated values of 14.8 cm and 20.3 cm, and 20.3 for
age I and II for fish off southwest Africa. 5
gave range values
from 9-15.3 cm, 17.0-23.1 cm, 23.8-28.5 cm, 29.0-32.2 cm,
and 32.4-34.8 cm for ages 1, II, III, IV, and V years,
respectively for Senegal [21, 22]
. present length-at-age estimates
of 14.4 cm, 23.6 cm, 29.3 cm and 33.0 cm for age groups 1, II,
III, and IV. From these, estimates of L = 0.43 year1
were
obtained for Balistees capriscus from Ghana. Approximate
average lengths for fish aged 1, 2, 3, 4, 5, 10, and 12 years are
10.9 cm, 22.6 cm, 30.2 cm, (0.59 kg), 35.6 cm (1.45 kg), 54.6
cm and 55.9 cm13
. The studies above indicated that size-at-age
for African fish are different than the Gulf of Mexico. These
differences may be the result of different environments,
biology, methods of capture, or ageing [11]
.
The ELEFAN I programme exercise produced the following
growth parameters. L∞: 283.90 cm and K = 0.75 (annual). The
M arrived by the equation is 0.80. However, being pelagic
species the same is multiplied with 0.8 as suggested by26
. Most
studies indicate gray triggerfish, Balistes capriscus reach
sexual maturity at 2 years, but may mature at 1 year [42, 21]
, 1.5
years [22]
, to up to 3 years [13]
. Balites vetula (Queen
triggerfish) from Puerto Rico and the Virgin Islands, estimated
growth rate to be K = 0.30 with fish being 16 cm in length
after14.
Off the east coast of Brazil, growth of the Queen
triggerfish was estimated to be K = 0.7619
, while off the central
coast of Brazil growth was found to be much slower, with K =
0.142
.
Total mortality coefficient (Z) was estimated by the catch
curve method for the period 2011-2012. The average Z during
the last seven years was 1.07 (Fig.2). Natural mortality was
0.80 (M) and fishing mortality was 0.27. The exploitation rate
(F/Z) estimated was 0.25 (Fig.5). This red toothed was found
to have two recruitment seasons, one major season, during
August and a minor season during July (Fig.4). The
recruitment of this species were February – April, and the peak
was in March by [29]
(Fig. 3). Keeping in view of the above;
the present estimates of K 0.75 and L∞ 283.90 cm appears to
be reasonable estimate. The resource appears to be under
exploited from Thoothukudi coast of Gulf of Mannar.
Length calculated for different years using von Bertalanffy’s
growth equation was plotted along with the observed length of
the same period which showed a general agreement in the
growth pattern. This also showed high degree of agreement
with other methods employed. Ford-Warlford graph was
constructed for O. niger by plotting Lt + 1 against Lt where Lt
is the height of the animal at a particular age. Lt + 1 when
intersected by a 45º diagonal from the origin, L (length at
infinity) was obtained and it was found to be 283.90 cm for
this species. In the present study, age and growth were studied
through different methods. However, von Bertalanffy’s
equation showed agreement and gave reliable results. This red
toothed trigger fish was found to have two recruitment
seasons, one major season, during August and a minor season
during January to March (Fig.4).
3.3 Length-weight relationship
The smallest length recorded for Odonus niger species was 80
mm while the largest being 310 mm and the body weight
between 15 g and 620 g. The length-weight relationship of O.
niger was W = 0/0002 L 2.2
. Odonus niger increased in weight
by a power of cube and less than cube of length. The
calculated slope value was 2.16 for males and 2.25 for females
by [40]
. The slope value (b) estimated for Balistoides
viridescens of both sexes was found to be 1.0541. The slope
value (b) estimated for Balistoides viridescens male was found
to be 1.4070 and for female 1.2257. The regression equations
calculated for female was Log W = -0.4394 + 1.2257 Log L,
and for male Log W = -0.7044 + 1.4070 [41]
.
[30]
studied the length-weight relationship of Odonus niger and
Balistapus undulates and reported the slope value of 3.0 and
3.6 for both the sexes. In the present study, slope value was
higher in females compared to males [34]
. reported a slope
value of 2.87 and 2.93 for both the sexes of Balistes vetula and
Xanthichthys ringens. A good correlation was consistently
observed between length and weight by [16]
for Rhinecanthus
rectangulus [18]
. studied more length gain and the recorded a
slope value of 2.96 for both sexes. Thus comparing the slope
of Odonus niger with other species of the balistids, it could be
concluded that the slope value is less than 3 for both the sexes
of Odonus niger [36]
. reported b value of 2.08 from Gulf of
Mannar, whereas [40]
reported ‘b’ value for male and females
was 2.1 – 2.2 of this species, southeast coast of India. 29
have
obtained ‘b’ value was 2.5 of this species, southwest coast of
India. The length-weight relationship of S. fraenatus obtained
by4
from the fish landing at Tuticorin fisheries harbour had ‘b’
value of 2.43 and Z. niger had ‘b’ value of 2.73. [20]
obtained
‘b’ value of 2.950 for S. fraenatus and ‘b’ value of 2.69 for
Abalistes stellatus from New Caledonia. According to [15]
the
value of the exponent ‘b’ in the parabolic equation usually lies
between 2.5 and 4.
3.4 Yield per recruit and biomass per recruit
The estimated length at first capture (Lc) was 0.025 cm. The
relative yield per recruit and biomass per recruit were
determined as a function of Lc/L∞ and M/K ratio, which are
0.03 and 1.06 respectively. The plot of yield per recruit (Y/R)
against E is shown in Fig 6. The maximum Y/R was at E =
0.25. The present E (0.25) has not exceeded the optimum
exploitation rate (Emsy = which maintain the 50% of the stock
biomass). It is suggested that for attaining the maximum yield
per recruit the fishing pressure may be increased for O. niger
(Fig 7). There is increasing recognition of the need to conserve
reef fish stocks and to gather the information necessary to
identify levels of vulnerability based on life history features.
31
identified extended life-spans, slow growth rates, and low
natural mortality rates as characteristics that will render marine
species vulnerable to extinction through human acidities,
including overexploitation. Research on the biology of
balistids, particularly in terms of demographic and
reproductive studies, is urgently needed to support efforts in
conservation and management of exploited balistids species.
Although marine reserves offer a precautionary approach by
allowing management or conservation to occur without
detailed technical and scientific capacity, their effectiveness is
also dependent on education, awareness and as [32, 33]
point out,
local fishing community support and the response of fish
populations to reduced exploitation. Hence, the integral role
4.
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International Journal of Fisheries and Aquatic Studies
stakeholders must play in order to achieve a successful
outcome.
Fig 1: Estimation of growth parameter through ELEFAN I
programme of Odouns niger
Fig 2: Total mortality estimates by-catch curve method during Jan
2011 – Dec 2012 of Odonus niger
Fig 3: Recruitment pattern of Odonus niger
Fig 4: Relative yield-per-recruit and biomass-per-recruit Odonus
niger (Lc /L∞ = 0.025, M/K = 1.06
Fig 5: Yield/Recruit and Biomass/Recruit of Odonus niger
Fig 6: Yield isopleth of Odonus niger
Fig 7: Estimation of Lα and Z/K of Odonus niger (Sexes pooled)
using Powell-Wetherall Plot
5.
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International Journal of Fisheries and Aquatic Studies
Fig 8: von Bertalanffy growth curve of Odonus niger (Growth
parameter from observed data)
4. References
1. Anonymous. Report of the ad hoc working group on
Sardinella off the coast of Ivory Coast-Ghana-Togo. FAO,
CECAF/ECAF Series 8012 (EN), 1980, 72.
2. Albuquerque CQ, Martins AS, Liete Jr NO, Araujo JN,
Ribeiro AM. Age and growth of the queen triggerfish
Balistes vetula (Tetradontiformes, Balistidae) of the
central coast of Brazil. Brazilian Journal of Oceanography
2011; 59:231-239
3. Beverton RJH, Holt SJ. A review of the spans and
mortality rates of fish in nature and their relation to
growth and other physiological characteristics. In: G. E.
W. Wolsteholme and M. O. Connor (Eds.) The Life Span
of Animals. CIBA Foundation colloquia on ageing,
London, Churchill, 1959; 5:142-180.
4. Balasubramanian TS, Rajapackiam S, Ameer Hamsa
KMS H Mohamad Kasim, on the bumper catch of
balistids from Tuticorin with notes on length-weight
relationship and gut contents. Mar. Fish. Infor. Serv., T &
E ser 1995; 137:18-19.
5. Caveriviere A, Kulbicki M, Konan J, Gerlotto F. Bilan des
cormaissances actuelles sur Balistes carolinensis dans le
Golfe de Guin6e. Doc. Sci. Centre Rech. Oceanogr.
Abidjan 1981; 12(l):1-78.
6. Gayanilo Jr FCP, Sparre, Pauly D. The FAO-ICLARM
stock assessment Tools (FiSAT) user's guide. FAO
computerized information series: fisheries, FAO, Rome,
Italy, 1995.
7. Gayanilo, Jr FC, Pauly D. The FAO-ICLARM stock
assessment tools (FiSAT) reference manual. FAO
computerized information series: fisheries. FAO, Rome
1997; 8:262.
8. Gulland JA. 1971. The Fish Resources of Ocean. West By
fleet, Survey, Fishing News (Book) Ltd. FAO, 255.
9. Hood PB, Johnson AK. A study of the age structure,
growth, maturity schedules and fecundity of gray
triggerfish (Balistes capriscus), red porgy (Pagrus
pagrus), and vermillion snapper (Rhomboplites
aurorubens) from the eastern Gulf of Mexico. MARFIN
Final Report, 1997.
10. Ingram G. W. Jr. Stock structure of gray triggerfish,
Balistes capriscus, on multiple spatial scales in the Gulf of
Mexico. Doctoral dissertation. University of South
Alabama, 2001.
11. Johnson AG, Saloman CH. Age, growth, and mortality of
gray triggerfish, Balistes capriscus, from the northeastern
Gulf of Mexico. Fish. Bull 1984; 82(3):485-492.
12. MacKichan CA, Szedlmayer ST. Reproductive behavior
of gray triggerfish, Balistes capriscus, in the Northeastern
Gulf of Mexico. Proceedings of the 59th Gulf and
Caribbean Fisheries Institute 2007; 59:231-235.
13. Manooch CS, III. Fishermans Guide. Fishes of the
southeastern United States. North Carolina Museum of
Natural History, Raleigh, NC, 1984.
14. Manooch CS, Drennon CL. Age and growth of yellowtail
snapper and queen triggerfish collected from the U. S.
Virgin Islands and Puerto Rico. Fisheries Research, 1987;
6:53-68.
15. Martin VR. The mechanics of environmental control of
body from in fishes. Pub. Out. Fish. Res. Lab 1949;
48:311-317.
16. Matsuura K. Balistidae. Triggerfishes. In K.E. Carpenter
and V. Niem (eds.) FAO species identification guide
forfishery purposes. The living marineresources of the
Western Central Pacific. Bony fishes part 4 (Labridae to
Latimeriidae), estuarine crocodiles. FAO, Rome, 2001;
6:3911-3928.
17. Moore JL. Age, growth and reproductive biology of the
gray triggerfish (Balistes capriscus) from the southeastern
United States, 1992-1997. Master‟s thesis, University of
Charleston, Charleston, 2001.
18. Myers RF. Micronesian reef fishes. SecondEd. Coral
Graphics, Barrigada, Guam, 1991, 298.
19. Netto RF, Di Beneditto APM. Growth, mortality, and
exploitation rates of queen triggerfish Balistes vetula
(Tetradontiformes: Balistidae) in the Brazilian East Coast.
Cahiers de Biologie Marine 2010; 51:93-99
20. Letourneur, M, Kulbicki, Labrosse P. Length-weight
relationship of fishes from coral reefs and lagoons of New
Caledonia – An update, Naga, ICLARM Q. 1998;
21(4):39-46.
21. Ofori-Danson PK. The biology of the triggerfish, Balistes
capriscus (Gmel.) in Ghanian waters. M.S.Thesis,
University of Ghana, Legon, 1981.
22. Ofori-Danson PK. Reproductive ecology of the
triggerfish, Balistes capriscus from the Ghanian coastal
waters. Trop. Ecol 1990; 31:1-11.
23. Pauly D, David N. ELEFAN I, A basic program for the
objective extraction of growth parameters from length –
frequency data. Meeresforsch 1981; 28(4):205-211.
24. Pauly D. Theory and Management of Tropical
Multispecies Stocks: A Review, with Emphasis on the
Southeast Asian Demersal Fisheries. ICLARM Studies
and Reviews, 1979; 1:35.
25. Pauly D. On the interrelationships between natural
mortality, growth parameters and mean environmental
temperature in 175 fish stocks. J. Cons. Int. Explor. Mer
1980; 39(3):175-192.
26. Pauly D. Some simple methods for the assessment of
tropical fish stocks. FAO. Fish. Tech. Paper Rome 1983;
2340:1-52.
27. Pauly D, Soriano ML. Some practical extensions to
Beverton and Holt’s relative yield-per-recruit model. In: J.
L. Maclean, L. B. Dizon and L. V. Hosillos (Eds.) The
First Asian Fisheries Forum. Asian Fisheries Society,
Manila, Philippines, 1986; 491-495.
28. Pauly D, Beyond our original horizons: the tropicalization
of Beverton and Holt. Rev. Fish Biol. Fish 1998; 8:307-
334.
29. Ramachandran S, Philip KP. Population dynamics of red-
toothed triggerfish Odonus niger (Ruppell, 1836) along
southwest coast of India. J. Mar. Biol. Ass. India, 2010;
52(1):105-108
30. Randall JE, Allen GR, Steene RC. Fishes of the Great
Barrier Reef and CoralSea. University of Hawaii press,
Honolulu, Hawaii, 1990, 506.
31. Robertson DR, Swearer SE, Kaufmann K, Brothers EB.
Settlement vs. environmental dynamics in a
pelagicspawning reef fish at Caribbean Panama. Ecol
Monogr 1999; 69:195-218.
32. Russ GR, Alcala AC. Marine reserves: rates and patterns
of recovery and decline of large predatory fish. Ecological
Applications 1996; 6(3):947-961.
33. Russ GR, Alcala AC. Marine reserves: long-term
protection is required for full recovery of predatory fish
population. Oecologia 2004; 138:622-627
34. Robins CR, Ray GC. A field guide to Atlantic coast fishes
6.
~ 209 ~
International Journal of Fisheries and Aquatic Studies
of North America.Houghton Mifflin Company, Boston,
U.S.A. 1986, 354.
35. Saeger J, Gayanilo FJ. A revised and graphics oriented
version of ELEFAN I and II badic programs for use on
HP/86/87 micro computers. Tech. Res. Dept. Marine Fish
1986; 8:1-233.
36. Satish Sahayak. Length-weight relationship of Suflamen
fraenatus (Latreille, 1804) and Zenodon niger (Ruppell,
1835). Indian J. Fish., 2005; 52(3):357-360.
37. Sedar. Stock assessment report 1 of SEDAR 9: Gulf of
Mexico gray triggerfish.Southeast Data, Assessment, and
Review. North Charleston, South Carolina, 9, 2006a.
http://www.sefsc.noaa.gov/sedar/
38. Simmons CM, Szedlmayer ST. Territoriality, reproductive
behavior, and parental care in gray triggerfish, Balistes
capriscus, from the northern Gulf of Mexico. Bulletin of
Marine Science 2012; 88:197-209
39. Sparre P, Venema SC. Introduction to tropical fish stock
assessments Part I- Manual. F.A.O. Fish. Tech. Pap 1993;
306:376.
40. Vaitheeswaran T, Venkataramani VK, Length-Weight
relationship of Odonus niger (Ruppell, 1836). Tamilnadu
J. Veterinary & Animal Sciences, 2008; 4(2):48-51.
41. Vaitheeswaran TK Prabakar S, Malathy, Neethiselvan N.
Length-Weight relationship of Titan triggerfish
Balistoides viridescens (Block and Schneider, 1801)
(Family: Balistidae) Off Thoothukudi coast of Gulf of
Mannar, Southeast coast of India (08° 53.6’N 78° 16’E
AND 08° 53.8’N 78° 32’E) – (36 M)”. International
Journal of Fisheries and Aquatic Studies, India, 2015;
2(5):32-35
42. Wilson CA, Nieland DL, Stanley AL. Age, growth, and
reproductive biology of gray triggerfish, Balistes
capriscus, from the Northern Gulf of Mexico Commercial
harvest. MARFIN Final Report. Louisiana State
University, Baton Rouge, Louisiana, 8 Figs 1995, 19.