scholarly journals Growth and Mortality of Sillago sihama (Forsskål) from Karachi Coast, Pakistan

2020 ◽  
pp. 42-52
Author(s):  
Abdul Baset ◽  
Qun Liu ◽  
Baochao Liao ◽  
Abdul Waris ◽  
Han Yanan ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Seawater Temperature ◽  
Total Mortality ◽  
Growth Function ◽  
Power Coefficient ◽  
Frequency Data ◽  
Length Frequency ◽  
Von Bertalanffy Growth Function ◽  
Sillago Sihama ◽  
Length Frequency Data

Length frequency data of silver sillago, Sillago sihama (Forsskål) were collected and measured from the fisherman catches using beach seines and handlines, at random, during 2012 from the Karachi coast of Pakistan. In this study, 1846 fish individuals (male and female combined) were collected ranging from 10 to 24 cm with dominant individuals ranged 12 to 16 cm (total length). Weight ranging was measured from 9 to 110 g. The above length-frequency data were analysed for the estimation of growth and mortality parameters. The power coefficient b of length-weight, the relationship was estimated at 2.9177. The estimated von Bertalanffy growth, function parameters of 25.20 cm (L∞) and 1.00 year-1 (K) were calculated by ELEFAN method equipped on FiSAT computer package. With length-converted catch curve analysis, the total mortality rate (Z) and its 95% confidence interval were 2.42 (2.174-2.669) year-1. The natural mortality rate (M) was 1.84 year-1 calculated with Pauly’s equation (the annual average seawater temperature was 27°C). Therefore, the fishing mortality rate was Z-M= 0.5787year-1. The exploitation ratio (E) estimated as F/Z=0.239 which is less than biological reference point (0.5), therefore it indicates that the stock of S. sihama was exploited at managed.

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 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.

Growth, mortality, ovarian maturity, and exploitation of the Guinea shrimp, Holthuispenaeopsis atlantica (Balss, 1914) (Decapoda: Dendrobranchiata: Penaeidae) in inshore waters of Ghana, West Africa

2020 ◽  
Vol 40 (3) ◽  
pp. 247-255
Author(s):  
Paulina Okpei ◽  
Joseph Aggrey-Fynn ◽  
Isaac Okyere
Keyword(s):  
West Africa ◽  
Growth Parameters ◽  
Total Mortality ◽  
Growth Function ◽  
Frequency Data ◽  
Length Frequency ◽  
Inshore Waters ◽  
The Mean ◽  
Ovarian Maturity ◽  
Length Frequency Data

Abstract The Guinea shrimp, Holthuispenaeopsis (= Parapenaeopsis) atlantica (Balss, 1914) is exploited by traditional and commercial fisheries in the Gulf of Guinea, West Africa. We assessed growth, mortality, ovarian maturity, and exploitation of the population of the species in inshore waters of Ghana as a contribution of filling the knowledge gap on the species. Samples were obtained from fish landing sites from three different coastal towns in Ghana from October, 2017 to May, 2018. Length-frequency data were used to estimate growth, mortality and exploitation ratio. The modal class for males was 6.0–6.9 cm total length (TL) and 9.0–9.9 cm TL in females. The length and weight relationship established that growth in both sexes was negatively allometric. The estimated growth parameters from the length frequency data fitted with the von Bertalanffy growth function were asymptotic length (L∞) of 10.08 cm for males and 15.4 cm for females. The growth constant (K) was calculated as 0.99 yr–1 for males and 0.89 yr–1 for females. The mean length-at-first capture (Lc) was found to be lower than the mean length at sexual maturity (Lm). The sex ratio showed a preponderance of females over males throughout the period, with 76.21% females. The total mortality rate (Z) for males was more than for females. The estimated natural mortality was 2.32 yr−1 for males and 1.93 yr−1 for females (M) whiles fishing mortality (F) rate was 1.22 yr−1 for males and 1.46 yr−1 for females. The exploitation ratio showed the stocks were not over-exploited. The estimated population parameters of the species obtained should be significant for the sustainable management of this resource.

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 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

Population Biology of the Goby Pseudapocryptes elongatus (Cuvier, 1816) in the Coastal Mud Flat Areas of the Mekong Delta, Vietnam

2007 ◽  
Vol 20 (2) ◽  
Author(s):  
T.D. DINH ◽  
M.A. AMBAK ◽  
A. HASSAN ◽  
N.T. PHUONG
Keyword(s):  
Population Biology ◽  
Relative Yield ◽  
Mekong Delta ◽  
Total Mortality ◽  
Fish Stock ◽  
Frequency Data ◽  
Length Frequency ◽  
Total Length ◽  
Mud Flat ◽  
Length Frequency Data

The goby, Pseudapocryptes elongatus, is an amphibious fish and common in the coastal mud flat areas of the Mekong Delta, Vietnam. The fish population was examined to obtain the information required for sustainable use and aquaculture development. Length frequency data of the fish ranging from 9.0 to 24.0 cm total length were analyzed using the FiSAT II software. The parameters of von Bertalanffy growth function fit to the length frequency data were L∞ = 26 cm, K = 0.65 yr-1, and to = - 0.26 yr-1. The longevity (tmax) was 4.35 yrs. There were two recruitment peaks with very different magnitudes and the means of the two peaks were separated by an interval of 5 months. Length at first capture (Lc) was 11.75 cm. The fishing mortality (F = 1.47 yr-1) and natural mortality (M = 1.44 yr-1) accounted for 51 and 59% of the total mortality (Z = 2.91 yr-1), respectively. Relative yield-per-recruit and biomass-per-recruit analyses gave Emax = 0.74, E0.1 = 0.61 and E0.5 = 0.35. The breeding season was extended during the rainy season, with the spawning peaks in July and October. Length at first maturity (Lm) was estimated at 15.4 and 16.3 cm for females and males, respectively. The batch fecundity estimates ranged from 2,652 to 29,406 hydrated oocytes per ovary in the fish specimens ranging from 12.8 to 22.4 cm total length. Results show that the fish stock is subjected to growth overexploitation.

scholarly journals Investigation and Development of Post-Season Modelling of Arrow Squid in the Snares and Auckland Islands

2021 ◽  
Author(s):  
◽  
Vidette Louise McGregor
Keyword(s):  
Automatic Differentiation ◽  
Integrated Model ◽  
Current Data ◽  
Management Approach ◽  
Frequency Data ◽  
Catch Per Unit Effort ◽  
Length Frequency ◽  
Model Builder ◽  
Set Up ◽  
Length Frequency Data

<p>Squid fisheries require a different management approach to most fish species which are much longer living. Most squid live for around one year, spawn and then die. The result of this is an entirely new stock each year with little or no relationship of stock sizes between the years. Hence, it is difficult to set appropriate catch limits prior to the season. Currently, there is nothing set up for modelling the New Zealand squid fishery in-season or post-season. In-season management would allow for adjustments of catch limits during a season. Post-season management would provide information on how much the stock was exploited during a season (described as the escapement). I have produced an integrated model using ADMB (Automatic Differentiation Model Builder) (Fournier et al., 2011) which models length frequency data, CPUE (Catch Per Unit Effort) indices and catch weights from a season. It calculates escapement which indicates how much the fishery is currently being exploited. In running the model against data from four area and year combinations, I found the escapement calculation to be stable. The results suggest this modelling approach could be used with the current data collected for post-season modelling of the fishery. I am less confident about in-season modelling with the current data collected. The integrated model fits quite poorly to the CPUE data, suggesting some discrepancy either between the data or the assumptions made of them. Sampling from a greater number of tows is recommended to improve the length frequency data and this may also improve the ability of the model to fit both to these and the CPUE.</p>

scholarly journals Investigation and Development of Post-Season Modelling of Arrow Squid in the Snares and Auckland Islands

2021 ◽  
Author(s):  
◽  
Vidette Louise McGregor
Keyword(s):  
Automatic Differentiation ◽  
Integrated Model ◽  
Current Data ◽  
Management Approach ◽  
Frequency Data ◽  
Catch Per Unit Effort ◽  
Length Frequency ◽  
Model Builder ◽  
Set Up ◽  
Length Frequency Data

<p>Squid fisheries require a different management approach to most fish species which are much longer living. Most squid live for around one year, spawn and then die. The result of this is an entirely new stock each year with little or no relationship of stock sizes between the years. Hence, it is difficult to set appropriate catch limits prior to the season. Currently, there is nothing set up for modelling the New Zealand squid fishery in-season or post-season. In-season management would allow for adjustments of catch limits during a season. Post-season management would provide information on how much the stock was exploited during a season (described as the escapement). I have produced an integrated model using ADMB (Automatic Differentiation Model Builder) (Fournier et al., 2011) which models length frequency data, CPUE (Catch Per Unit Effort) indices and catch weights from a season. It calculates escapement which indicates how much the fishery is currently being exploited. In running the model against data from four area and year combinations, I found the escapement calculation to be stable. The results suggest this modelling approach could be used with the current data collected for post-season modelling of the fishery. I am less confident about in-season modelling with the current data collected. The integrated model fits quite poorly to the CPUE data, suggesting some discrepancy either between the data or the assumptions made of them. Sampling from a greater number of tows is recommended to improve the length frequency data and this may also improve the ability of the model to fit both to these and the CPUE.</p>

scholarly journals Age, growth and mortality of the anchovy Stolephorus commersonnii (Lacepède,1803) (Clupeiformes) caught off the coast of Tanga, Tanzania

2021 ◽  
pp. 95-104
Author(s):  
Albogast T. Kamukuru ◽  
Shigalla B. Mahongo ◽  
Baraka C. Sekadende ◽  
Joseph S. Sululu
Keyword(s):  
Software Tool ◽  
Growth Function ◽  
Fishing Effort ◽  
Northern Coast ◽  
Management Intervention ◽  
Von Bertalanffy Growth Function ◽  
Relationship Model ◽  
June July ◽  
Spawning Periods ◽  
Length Frequency Data

The population dynamics of Stolephorus commersonnii (Lacepède, 1803) from a ringnet fishery operating off the northern coast of Tanga Region were evaluated based on monthly length-frequency data collected from August 2016 to August 2017. The total length (TL) and total weight (TW) of 14,410 individuals ranged from 22 to 130 mm and from 0.39 to 14.64 g respectively. S. commersonnii exhibited a negative allometric growth pattern with the length-weight relationship model: W = 0.00001 x L2.886. The von Bertalanffy growth function was Lt = 86.03 x (1 – e–1.19(t – (–0.01))) using ELEFAN I from the FiSAT II software tool package. Growth performance index and longevity were estimated at (ɸ) = 3.9 and Tmax = 2.5 yrs, respectively. The total (Z), fishing (F) and natural (M) mortalities were determined at 1.39, 0.53 and 0.86 yr-1, respectively. The current exploitation rate (Ecur) was estimated at 0.38. S. commersonnii exhibited a year-round breeding pattern, with two recruitment peaks in March and June/July. Length-at-first-capture (Lc50) and length-at-first-sexual maturity (Lm50) were 40.51 and 57.35 mm TL, respectively, suggesting growth overfishing. The stock of anchovy indicates an overfishing scenario requiring management intervention such as reducing fishing effort levels, increasing mesh sizes and introducing seasonal closures during peak spawning periods.

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