scholarly journals Population Dynamics of Mud Crab (Scylla serrata) in the Southeastern Coastal Region of Bangladesh

2006 ◽  
Vol 19 (1) ◽  
Author(s):  
M. ZAFAR ◽  
S.M. NURUL AMIN ◽  
M.M. RAHMAN
Keyword(s):  
Growth Parameters ◽  
Coastal Region ◽  
Scylla Serrata ◽  
Frequency Data ◽  
Population Parameters ◽  
Mud Crab ◽  
Length Frequency ◽  
Southeastern Part ◽  
Male And Female ◽  
Length Frequency Data

Population parameters of male and female Scylla serrata were estimated using FiSAT software with length-frequency data collected from different areas of Cox’s Bazar, southeastern part of Bangladesh (Chakaria Sundarban, Moheshkhali and Kutubdia channel) to evaluate the growth parameters, mortality rates and exploitation levels. Asymptotic length (L∝) was 105.9 mm and 105 mm, and growth co-efficient (K) was 0.28/yr and 0.36/yr for male and female S. serrata, respectively. The natural mortalities of S. serrata were 0.49/yr and 0.58/yr and fishing mortalities were 0.35/yr and 0.38/yr for male and female accordingly. Recruitment of this species into the fishery takes place throughout the year. The exploitation level for S. serrata was found to be 0.41 for the male and 0.39 for the female. This study showed that the stocks of male and female S. serrata were not under fishing pressure (E< 0.50) in the Southeastern part of Bangladesh.

Carapace width-weight relationship, age, growth and longevity of the mud crab Scylla olivacea (Herbst, 1796) in the Pichavaram mangroves, south-east India

2015 ◽  
Vol 96 (7) ◽  
pp. 1379-1386 ◽  
Author(s):  
C. Viswanathan ◽  
M. Pravinkumar ◽  
T.V. Suresh ◽  
V. Elumalai ◽  
S.M. Raffi
Keyword(s):  
East Coast ◽  
Growth Parameters ◽  
Carapace Width ◽  
Data Sets ◽  
Frequency Data ◽  
Mud Crab ◽  
Length Frequency ◽  
Males And Females ◽  
And Control ◽  
Length Frequency Data

The present study provides novel information on carapace width-weight (CWR) relationship and growth parameters of the mud crab Scylla olivacea (Herbst, 1796) inhabiting the Pichavaram mangroves, east coast of India based on length frequency data sets during June 2010 to May 2012. CWR revealed linear regression between carapace width and weight in both sexes, and overall CWR exponent (b) values acquired for males and females are 3.035 (r2 = 0.962) and 2.925 (r2 = 0.933) respectively. The growth parameters, CW∞, K and to derived for males and females were 148.05, 0.762 year−1 and −0.637 and 138.80 mm, 0.856 year−1 and −0.681 respectively. The growth of S. olivacea was assessed through various methods in such a way that the outcome of one method functions as a rider, check and control over the other.

Effect of individual variability on estimation of population parameters from length-frequency data

1998 ◽  
Vol 55 (11) ◽  
pp. 2393-2401 ◽  
Author(s):  
You-Gan Wang ◽  
Nick Ellis
Keyword(s):  
Growth Parameters ◽  
Growth Parameter ◽  
Individual Variability ◽  
Fish Stock ◽  
Frequency Data ◽  
Population Parameters ◽  
Length Frequency ◽  
The Moment ◽  
The Individual ◽  
Length Frequency Data

We consider estimation of mortality rates and growth parameters from length-frequency data of a fish stock when there is individual variability in the von Bertalanffy growth parameter Linfinity and investigate the possible bias in the estimates when the individual variability is ignored. Three methods are examined: (i) the regression method based on the Beverton and Holt's (1956, Rapp. P.V. Reun. Cons. Int. Explor. Mer, 140: 67-83) equation; (ii) the moment method of Powell (1979, Rapp. P.V. Reun. Int. Explor. Mer, 175: 167-169); and (iii) a generalization of Powell's method that estimates the individual variability to be incorporated into the estimation. It is found that the biases in the estimates from the existing methods are, in general, substantial, even when individual variability in growth is small and recruitment is uniform, and the generalized method performs better in terms of bias but is subject to a larger variation. There is a need to develop robust and flexible methods to deal with individual variability in the analysis of length-frequency data.

scholarly journals POPULATION DYNAMICS OF MALAYAN LEAF FISH (Pristolepisgrooti Blkr.) IN RANAU LAKE, SOUTH SUMATRA

2018 ◽  
Vol 24 (2) ◽  
pp. 125
Author(s):  
Sevi Sawetri ◽  
Subagdja Subagdja ◽  
Dina Muthmainnah
Keyword(s):  
Mortality Rate ◽  
Growth Parameters ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Frequency Data ◽  
Length Frequency ◽  
Lake Ecosystems ◽  
Exploitation Rate ◽  
Length Frequency Data

The Malayan leaf fish or locally named as kepor (Pristolepis grooti) is one of important biotic components in Ranau Lake ecosystems. This study aimed to estimate population dynamic and exploitation rate of kepor in Ranau Lake, South Sumatera. The population parameters are estimated based on length frequency data which were collected in March to October 2013. Growth parameters and fishing mortality rates were calculated using FiSAT software package. The results showed that kepor’s growth was negative allometric, which tended to gain length faster than weight. Kepor population was dominated (42%) by individual length of 10.0 to 11.0 cm. Predicted length infinity (L) was 17.28 cm with high value of growth rates (K) of 1.4 year-1. The natural mortality rate (M) is 2.57 year-1, the fishing mortality rate (F) is 5.36 year-1 and total mortality rate (Z) is 7.93 year-1. The exploitation rate of Malayan leaf fish in Ranau Lake (E = 0.68 year-1) has passed the optimum score.  

Length-weight relationship, growth and mortality ofAnadara granosain Penang Island, Malaysia: an approach using length-frequency data sets

2014 ◽  
Vol 95 (2) ◽  
pp. 381-390 ◽  
Author(s):  
Mohammad Reza Mirzaei ◽  
Zulfigar Yasin ◽  
Aileen Tan Shau Hwai
Keyword(s):  
Growth Parameters ◽  
Total Mortality ◽  
Growth Function ◽  
Data Sets ◽  
Frequency Data ◽  
Length Frequency ◽  
Frequency Distributions ◽  
Weight Relationship ◽  
Logarithmic Relationship ◽  
Length Frequency Data

Length-weight relationship, growth parameters and mortality rates ofAnadara granosain the intertidal zone of Balik Pulau, Penang Island, West Coast of Malaysia were investigated based on monthly length-frequency data (December 2011 to November 2012). A total of 548 individuals ranging from 11.25 to 33.13 mm size were subjected to analysis. Logarithmic relationship between the length and weight was LogW = 2.328LogL − 2.537 (R2 = 0.922) for combined sexes. From this equation it was clear that the exponent ‘b’ value forA. granosashowed a negative allometric growth (b < 3). A von Bertalanffy growth function with an asymptotic length (L∞) of 35.40 mm and a growth constant (K) of 1.1 year−1was established from length frequency distributions. Thet0(−0.140) was estimated by substituting theL∞andKin the Pauly's equation. The sizes attained byA. granosawere 10.13, 14.36, 17.89, 20.82, 23.56 and 25.29 mm at the end of 2, 4, 6, 8, 10 and 12 months, respectively. The estimated growth performance index (Ø) was 3.13 while the estimated lifespan of the cockles was about 2.72 years at the study area. The estimated value of total mortality based on length-converted catch curve wasZ = 3.02 year−1. The natural mortality (M) and fishing mortality (F) rates were 1.84 and 0.48 year−1, respectively. The exploitation level (E) ofA. granosawas 0.20, which indicated slight fishing pressure on the stock.

Estimation of change in lifetime egg production from length frequency data

2005 ◽  
Vol 62 (7) ◽  
pp. 1626-1639 ◽  
Author(s):  
Michael R O'Farrell ◽  
Louis W Botsford
Keyword(s):  
Mortality Rate ◽  
Reference Point ◽  
Egg Production ◽  
Growth Parameters ◽  
Estimation Method ◽  
Natural Mortality ◽  
Frequency Data ◽  
Length Frequency ◽  
Estimation Model ◽  
Length Frequency Data

The percentage of unfished lifetime egg production (LEP) has been used to represent persistence in precautionary fisheries management, but estimation of this reference point requires substantial data and it is sensitive to errors in natural mortality rate. We present an estimation method that quantifies the change in LEP by a fishery when only length frequency samples, one early in the fishery and one recent, are available for assessment. Using simulated length frequency data with known parameter values, estimates of LEP had undetectable bias when challenged with random sampling variability and sample sizes as low as 100. Simulation of artificial data with (i) growth parameters that differed from the estimation model, (ii) transient size structures, and (iii) recruitment variability led to predictably biased estimates. In a direct comparison with the spawning potential ratio reference point, fractional LEP was much less sensitive to errors in natural mortality rate. Application of this method to length frequency data for blue rockfish (Sebastes mystinus) for years between 1980 and 2003 suggests that during this interval, LEP has been reduced to levels of concern.

scholarly journals Growth, Mortality and Exploitation Levels of Sphyraena sphyraena (Pisces: Sphyraenidae) and Apsilus fuscus (Pisces: Lutjanidae) in Ghanaian Waters

2021 ◽  
Vol 2 (1) ◽  
pp. 16-23
Author(s):  
Joseph Aggrey-Fynn ◽  
Divine Worlanyo Hotor
Keyword(s):  
Growth Parameters ◽  
Total Mortality ◽  
Growth Function ◽  
Frequency Data ◽  
Length Frequency ◽  
Fish Stocks ◽  
Von Bertalanffy Growth Function ◽  
Inshore Waters ◽  
The Mean ◽  
Length Frequency Data

Sphyraena sphyraena (Linnaeus, 1758) and Apsilus fuscus (Valenciennes, 1830) are commercially important fish species in Ghana. The stocks are exploited mainly by the artisanal and semi-industrial fisheries. Growth and mortality rates, and exploitation levels of the two stocks in inshore waters of Ghana were assessed as a contribution to fill the knowledge gap on the species. Samples were obtained from three landing sites along the coast of Ghana from February to July, 2017. Length-frequency data were used to estimate growth, mortality and exploitation ratios. The modal class for S. sphyraena was 37.0–39.9 cm total length (TL) and 34.0–35.9 cm TL for A. fuscus. The length and weight relationships established that growth in S. sphyraena was negative allometric, whereas that of A. fuscus was isometric. The estimated growth parameters from the length frequency data fitted with the von Bertalanffy growth function were asymptotic length (L∞) of 69.9 cm TL for S. sphyraena and 53.5 cm TL for A. fuscus. The growth constant (K) was calculated as 1.64 yr-1 for S. sphyraena and 0.50 yr-1 for A. fuscus. The mean length-at-first capture (Lc) was found to be lower than the mean length at sexual maturity (Lm) for both species. The sex ratio showed a dominance of females over males in S. sphyraena, and 1:1 for A. fuscus. The total mortality rate (Z) for S. sphyraena was more than for A. fuscus. The estimated natural mortality (M) was 1.88 yr-1 for S. sphyraena and 0.74 yr-1 for A. fuscus whilst fishing mortality (F) rate was 3.04 yr-1 for S. sphyraena and 0.93 yr-1 for A. fuscus. The exploitation ratio showed that both fish stocks were exploited over the optimum levels. The estimated population parameters of the species obtained from the study, therefore, might be useful for the sustainable management of the stocks.

scholarly journals PARAMETER POPULASI DAN BIOLOGI REPRODUKSI IKAN BENTONG (Selar crumenophthalmus) DI PERAIRAN KWANDANG,GORONTALO UTARA

2015 ◽  
Vol 6 (2) ◽  
pp. 111 ◽  
Author(s):  
Ria Faizah ◽  
Lilis Sadiyah ◽  
Tuti Hariati
Keyword(s):  
Total Mortality ◽  
Maturity Stage ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Frequency Data ◽  
Population Parameters ◽  
Length Frequency ◽  
Exploitation Rate ◽  
Length Frequency Data ◽  
Pelagic Fisheries

Perairan Kwandang merupakan salah satu basis utama perikanan pelagis kecil di perairan laut Sulawesi. Salah satu jenis yang banyak dimanfaatkan adalah ikan bentong (Selar crumenophthalmus). Penelitian ini bertujuan untukmenduga parameter populasi, tingkat pemanfaatan (E), dan biologi reproduksi dari ikan bentong. Data panjang cagak dikumpulkan dari PP Kwandang dari bulan Januari hingga November 2012. Pendugaan parameter populasi dilakukan dengan menggunakan metode Bhattacharya dengan bantuan software FISAT II Hasil analisis menunjukkan bahwa laju pertumbuhan (K) sebesar 0,76 per tahun dengan L”=24,7 cm. Laju kematian total (Z) sebesar 2,63 per tahun, dengan laju kematian alamiah (M) sebesar 1,28 per tahun, laju kematian akibat penangkapan (F) sebesar 1,3 per tahun dan laju pemanfaatan 0,51. Tingkat pemanfaatan ikan bentong sudah relatif optimum. Rasio jenis kelamin ikan bentong jantan dan betina adalah 1: 1,02. TKGI paling banyak ditemukan. Musim pemijahan ikan bentong diduga terjadi pada bulan November dan Desember.The Kwandang waters is one of the main base for small pelagic fisheries in Sulawesi sea. Bigeye scad (Selar crumenophthalmus) is one of species from small pelagic is exploited. The objectives of the research was to estimate the population parameters, exploitation rate and reproductive biology of bigeye scad. Length frequency data were collected from PP Kwandang, from January November 2012. Estimation of population parameters of bigeye scad used FISAT II method. The results showed that growth rate as follows (K) = 0,76 year-1 , L”=24,7 cm. Total mortality rate (Z) = 2,63 year-1, with natural mortality (M) = 1, year-1 and fishing mortality (F) = 1,3 year-1 and exploitation rate (E)=0,51. The exploitation rate are already optimum. Sex ratio of male and female are 1:1,02. The most commonly founded is Gonado Maturity Stage of I. The spawning season of bigeye scad estimated was November and December

MULTIFAN a Likelihood-Based Method for Estimating Growth Parameters and Age Composition from Multiple Length Frequency Data Sets Illustrated using Data for Southern Bluefin Tuna (Thunnus maccoyii)

1990 ◽  
Vol 47 (2) ◽  
pp. 301-317 ◽  
Author(s):  
D. A. Fournier ◽  
John R. Sibert ◽  
Jacek Majkowski ◽  
John Hampton
Keyword(s):  
Growth Parameters ◽  
Bluefin Tuna ◽  
Parameter Estimates ◽  
Data Sets ◽  
Frequency Data ◽  
Length Frequency ◽  
Objective Criterion ◽  
Southern Bluefin Tuna ◽  
Robust Likelihood ◽  
Length Frequency Data

We present a method for simultaneously analyzing multiple length frequency data sets. The method utilizes a robust likelihood-based estimation procedure that provides an objective criterion for hypothesis testing. The method is applied to length frequency data from southern bluefin tuna (Thunnus maccoyii) for which independent estimates of growth parameters based on tag return data are available. The estimates of the growth parameters from the new method were found to be in substantial agreement with the values previously obtained for these parameters. The strength of the likelihood approach is demonstrated by discriminating between alternative structural hypotheses for describing the data. The ability to simultaneously analyze multiple samples permits the method to exploit the extra information not available when analyzing samples one by one. The computer program maintains a database of fits to the data which enable the user to organize the results of the analysis. Graphical displays permit the user to view any of the fits, and an interactive graphics routine aids the user to find good initial parameter estimates.

scholarly journals Short Communication: Age and growth of elongated mudskipper, Pseudapocryptes elongatus (Cuvier, 1816) from Sundarbans, India

2018 ◽  
Vol 20 (1) ◽  
pp. 85-90 ◽  
Author(s):  
GOPALAN MAHADEVAN ◽  
PALANIVEL BHARATHIRAJAN ◽  
VELAYUTHAM RAVI ◽  
MOJTABA POULADI ◽  
MARYAM MIRZAEI VAND KHANGHAH
Keyword(s):  
Short Communication ◽  
Growth Parameters ◽  
Mathematical Expression ◽  
Fish Growth ◽  
Age And Growth ◽  
Von Bertalanffy ◽  
Frequency Data ◽  
Length Frequency ◽  
Males And Females ◽  
Length Frequency Data

Mahadevan G, Bharathirajan P, Ravi V, Pouladi M, Mirzaei Vand Khanghah M. 2019. Short Communication: Age and growth of elongated mudskipper, Pseudapocryptes elongatus (Cuvier, 1816) from Sundarbans, India. Biodiversitas 20: 85-90. The estimation of age and mathematical expression of fish growth is complex and debated subject in fishery sciences. Growth parameters of elongated mudskipper, Pseudapocryptes elongatus were estimated based on the length frequency data using FiSAT II software (several tools such as Powell-Wetherall method, ELEFAN and von Bertalanffy growth estimates). Samples were collected from Sundarbans mangroves using gill and cast nets and by hand picking. The length-frequency (LFQ) of P.elongatus was recorded from January 2014 to December 2015 and the above tools estimated the growth parameters (L∞, K and t0) from the progression of LFQ modes through time. L∞ and K values of males were 220.50 mm and 1.3 yr-1, respectively and similarly, L∞ and K values of females were 221.05 mm and 1.21 yr-1, respectively. The t0 values estimated for males and females were-0.1915 years and-0.1661 years, respectively. The estimated growth performance index (Φ) values for males and females of P. elongatus were 4.394 and 4.503, respectively. The lifespan of both the sexes was found to be 4+ years.

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