scholarly journals Population dynamics of Puntius sophore (Hamilton, 1822) of river Sutlej in Punjab (India)

2021 ◽  
Vol 42 (6) ◽  
pp. 1505-1511
Author(s):  
J. Kumar ◽  
◽  
S.N. Datta ◽  
G. Tewari ◽  
S.S. Hassan ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Extreme Values ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Maximum Sustainable Yield ◽  
Recruitment Pattern ◽  
Fish Market ◽  
Baseline Information ◽  
River Sutlej ◽  
Puntius Sophore

Aim: The aim of the present paper was to describe first and comprehensive picture on length-weight relationship and population dynamics of riverine Puntius sophore. The findings of the investigation will be an imperative part of the ecological database from river Sutlej. Methodology: The length-frequency data of 579 specimens of P. sophore captured from different stretches of river Sutlej were collected fortnightly from Tajpur fish market and Haibowal fish market (Devnagar) during April 2019 to March 2020. All the population parameters were analyzed using FiSAT II analytical package developed by FAO. Results: The estimated length-weight relationships (LWRs) of combined male and female was derived as W=0.1471 L3.0605 (r=0.98). The growth parameters were L∞=123.5 mm, K=1.18 yr-1, to= -0.7672 yr-1, Rn=0.215 and ø'=4.241. The estimated natural mortality coefficient (1.25 per yr) was greater than fishing mortality (1.03 yr-1).The present level of exploitation (E=0.45, U=0.40) of P. sophore stock indicated that stocks were under-exploited. Prediction of maximum length from extreme values at 95% confidence interval was calculated as 112.48-138.24 mm. The recruitment pattern of P. sophore showed peaks during May and June. Interpretation: The P. sophore stock was under-exploited. The fishing intensity may be standardized to obtain optimum yield per recruit and thereby ideal maximum sustainable yield. This baseline information will help in further studies on the stock assessment and formulating strategies for rational exploitation of the species.

scholarly journals Population Dynamics and Stock Assessment of Gudusia chapra (Hamilton-Buchanan) in the Rajdhala Reservoir, Netrakona, Bangladesh

2007 ◽  
Vol 19 (3) ◽  
Author(s):  
M. A. RAHMAN ◽  
M. M. HAQUE
Keyword(s):  
Population Dynamics ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Maximum Sustainable Yield ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Length Frequency ◽  
Recruitment Pattern ◽  
Pattern Maximum

Population dynamics and stock assessment of chapila (Gudusia chapra, Hamilton-Buchanan) in the Rajdhala reservoir, Netrakona, Bangladesh was studied from January 2003 to December 2004 using length-frequency based analysis of FiSAT software to evaluate the growth parameters, mortality rates, exploitation rates, recruitment pattern, maximum sustainable yield (MSY) and the corresponding fishing mortality at this level. The annual rates of natural mortality, fishing mortality and total mortality were 1.34, 1.37 and 2.71 yr-1 in 2003 and 1.37, 1.58 and 2.95 yr-1 in 2004 respectively. The study revealed that the fishes were recruited in the fishery twice a year and the fishes were harvested at a higher level than the optimum fishing pressure. Twenty four percent of the present exploitation pressure on chapila is suggested to be reduced to get the MSY of this fish from the reservoir.

Population dynamics and stock assessment of Hilsa shad, Tenualosa ilisha (Hamilton, 1822) along the coast of Bangladesh

2021 ◽  
Vol 48 (2) ◽  
pp. 231-241
Author(s):  
Md Khairul Islam ◽  
Md Humayun ◽  
Manmatha Nath Sarker ◽  
Md Sharifuddin ◽  
M Niamul Naser
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Population Analysis ◽  
Total Mortality ◽  
Maximum Sustainable Yield ◽  
Fishing Mortality ◽  
Recruitment Pattern ◽  
Weight Relationship ◽  
Tenualosa Ilisha ◽  
Highly Correlated

Stock Assessment of Tenualosa ilisha (Hamilton, 1822) were estimated using FiSAT-II software with length-frequency data collected from different landing centers. The Southeast Coast of Bay Of Bengal, Cox's Bazar. The Von Bertalanffy growth parameters Land K for the species were asymptotic length (L∞) was 51.41 cm, growth rate (K) was 0.75 year-1 and t0 = -0.2 year respectively. The estimated value of total mortality (Z) based on length converted catch curve using these growth parameters was 2.35 year-1.Natural mortality (M) based on growth parameters and mean environmental temperature (T = 27° C) was 1.00 year-1 and fishing mortality (F) was 1.35 year-1. Optimum length of hilsa at first capture (Lc=L50) was 28.36 cm TL. Growth performance indices (ϕ') was 3.30. The estimated value of the exploitation rate (E) using the length-converted catch curve was 0.57. The recruitment pattern of this species was continuous and two peaks per year. The present investigation clearly showed the over fishing (E > 0.50) condition for T. ilisha in Bangladesh. The estimated length-weight relationship for the combined sex was found to be W = 0.0109 L3. Virtual population analysis (VPA) showed that the maximum fishing mortality occurring in the length between 30 to 35 cm with a maximum value in the length of 32 cm that repeatedly indicate high fishing mortality in the T. ilisha. The generalized length-weight relationship was fitted with the pooled data of all monthly samples were BW = 0.029 TL2.718 (R2= 0.833) respectively. The results revealed that all length-weight relationships were highly correlated (r > 0.993). Maximum sustainable yield (MSY) was estimated as 435,554 t. Bangladesh J. Zool. 48(2): 231-241, 2020

Incorporating habitat preference into the stock assessment and management of blue marlin (Makaira nigricans) in the Pacific Ocean

2012 ◽  
Vol 63 (7) ◽  
pp. 565 ◽  
Author(s):  
Nan-Jay Su ◽  
Chi-Lu Sun ◽  
André E. Punt ◽  
Su-Zan Yeh ◽  
Gerard DiNardo
Keyword(s):  
Population Dynamics ◽  
Habitat Preference ◽  
Stock Assessment ◽  
Ecosystem Approach ◽  
Maximum Sustainable Yield ◽  
Blue Marlin ◽  
Makaira Nigricans ◽  
Biological Variables ◽  
Population Dynamics Model ◽  
Spawning Stock

Stock assessments that include a spatial component or relate population dynamics to environmental conditions can be considered one way of implementing an ecosystem approach to fisheries. A spatially-structured population dynamics model that takes account of habitat preference is developed and then applied to Pacific blue marlin (Makaira nigricans), as they prefer certain habitats and migrate seasonally. The model is fitted to fishery catch-rate and size data, along with information on the relative density of the population over space derived from a habitat preference model fitted to oceanographic and biological variables. Results show that blue marlin are more abundant in tropical waters, and females account for most of the biomass. Assessments that allow for environmental factors, movement dynamics and sexual dimorphism indicate that this population is in an over-exploited state, with current spawning stock biomass below the level corresponding to maximum sustainable yield (SMSY) and current fishing mortality exceeding that needed to achieve MSY (FMSY). A risk analysis based on samples from a Bayesian posterior distribution suggests that the population will remain above SMSY after 20 years if exploitation rates are below the level corresponding to FMSY.

scholarly journals Population Dynamics and Management of Invasive Blue Tilapia (Oreochromis aureus) in Garmat Ali River, Basrah, Iraq

2020 ◽  
pp. 44-54
Author(s):  
Abdul-Razak M. Mohamed ◽  
Ayat N. Salman
Keyword(s):  
Population Dynamics ◽  
Growth Parameters ◽  
Relative Yield ◽  
Total Mortality ◽  
Reference Points ◽  
Recruitment Pattern ◽  
Oreochromis Aureus ◽  
Biological Target ◽  
Blue Tilapia ◽  
Yield Per Recruit

The blue tilapia, Oreochromis aureus is an invasive species that has successfully established itself in most of the Iraqi waters. However, there is little information on the population dynamics of the species in these waters. Hence, the growth parameters, mortality rates, probability of capture, recruitment pattern and yield per recruit of blue tilapia in Garmat Ali River, Iraq was assessed using FiSAT II software. A total of 1664 blue tilapia fish were collected by different fishing gears from October 2019 to September 2020 for recording the relevant data. The length-weight relationship obtained was W=0.0147*L3.0748 for fish ranging from 7.5 to 26.3 cm total length suggesting that the species shows positive allometric growth. The asymptotic length (L∞), growth constant (K), theoretical age at zero-length (t0), growth performance index (Ø') and longevity (tmax) were 29.9 cm, 0.205, -1.293, 2.345 and 10.7 years, respectively. The total mortality (Z), natural (M), fishing (F) and exploitation (E) were 1.09, 0.61, 0.48 and 0.43, respectively. Length at first capture (L50) was found to be 13.92 cm. The main recruitment pulse was from March to July with a peak in April, which account for 18.4% of the total recruitment in the year. The relative yield per recruit analysis revealed that the present exploitation rate (Epresent) for blue tilapia was below than the biological target reference points (E0.1 and Emax), which denotes that this stock was not over-exploited. For management purposes, higher yields can be achieved by reducing the mesh sizes of the nets during fishing.

Estimating some population parameters and stock assessment of Dark Sleeper Odontobutis potamophila in the Gaosha River, Wuyuan County, Jiangxi Province, China

2017 ◽  
Author(s):  
Wu Bin Wang Haihua ◽  
Fu Huiyun Zhang Yanping
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Landing Site ◽  
Jiangxi Province ◽  
Recruitment Pattern ◽  
Growth Coefficient ◽  
West Part ◽  
Exploitation Rate ◽  
Odontobutis Potamophila

A study was conducted to investigate the growth parameters, mortality and recruitment pattern of Odontobutis potamophila collected in the Gaosha river fish landing site, west part of Wuyuan County (Latitude: 29° 14' 29" N, Longitude: 117° 45' 49" E). O.potamophila were collected from November, 2013 to October, 2014. Growth parameters, asymptotic length (L) = 192mm and growth coefficient (k) = 0.22 year-1. Growth performance index(Ø’) =3.91, total mortality (Z) = 0.72 year-1, natural mortality (M) = 0.32 year-1, fishing mortality (F) = 0.40 year-1 and exploitation rate (E) = 0.55year-1.The estimated exploitation rate (E) has slightly exceeded the optimum value of E indicating this species was sustainable exploitation in the study area. The exploitation ratios were computed as Emax= 0.61, E10= 0.52, E50= 0.34. The length at first capture at 50%, (Lc) was 77 mm. The recruitment pattern of the species was found continuous all-round the year with one peak. The observation of the annual recruitment of O.potamophila found to occur from May to July. Steady biomass also increased with length class until 121-125 mm, and the total steady state biomass was found to be 2240 kg.

scholarly journals Stock Assessment of Lates niloticus in Upper Victoria Nile and its Impact on Uganda’s Economy

2021 ◽  
Vol 19 (2) ◽  
pp. 11-26
Author(s):  
Samuel Bassa ◽  
Albert Getabu ◽  
Erick Ogello ◽  
Anthony Taabu Munyaho ◽  
Dickson Oteino Owiti ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Nile Perch ◽  
Lates Niloticus ◽  
Slot Size ◽  
Catch Rates ◽  
A Minor

This study investigated the growth, mortality, recruitment, and catch estimates of Nile perch, Lates niloticus (Linnaeus, 1758), in Upper Victoria Nile, basing on total catches and length-frequency data collected between 2008 and 2018. The asymptotic length (L∞) had a value of 93.45 cm TL, growth curvature (K) was 0.446 year-1, total mortality (Z) was 1.85year-1, natural mortality (M) was 0.79 year-1, fishing mortality (F) was 1.09 year-1, exploitation rate (E) was 0.59 and growth performance index(ᴓ) of (L∞) was 3.604. There were two peaks recruitment period, a minor one in March and a major one in August. These respectively accounted for 12.8 and 26.3 percent of the total catch. The optimum sustainable yield (E0.5), maximum sustainable yield (Emax) and, economic yield (E0.1) was 0.278, 0.421 and 0.355 respectively. The findings suggest that there is a decline in the population of Lates niloticus in Upper Victoria Nile. Therefore, strict management of the fishery by adhering to the recommended slot size of 50-85 cm TL and curtailing use of illegal gears is needed. This will be possible through enforcement of regulations, monitoring, control and surveillance in order to ensure sustainability of the Nile perch fishery and ecosystem restoration in the Upper VictoriaNile.Keywords: Lates niloticus; Catch rates; Growth parameters, Upper Victoria Nile.

scholarly journals Population dynamics of anchovy pekto (Stolephorus waitei) in the waters of Malacca Strait, North Sumatra, Indonesia

2021 ◽  
Vol 22 (7) ◽  
Author(s):  
Miswar Budi Mulya ◽  
ARLEN HANEL JHON ◽  
ZULHAM APANDY HARAHAP
Keyword(s):  
Population Dynamics ◽  
Growth Parameters ◽  
Good Condition ◽  
Fork Length ◽  
Total Mortality ◽  
Recruitment Pattern ◽  
Water Region ◽  
Relationship Of ◽  
North Sumatra ◽  
Malacca Strait

Abstract. Mulya MB, Jhon AH, Harahap ZA. 2021. Population dynamics of anchovy pekto (Stolephorus waitei) in the waters of Malacca Strait, North Sumatra, Indonesia. Biodiversitas 22: 2693-2698. Anchovy pekto or Stolephorus waitei (Engraluidae: Clupeiformes) is one of the fish in the eastern coastal part of North Sumatra, occupying the waters of Malacca Strait. This research presents the population dynamics of S. waitei following its age, growth, mortality, and recruitment pattern based on the length-frequency data. Fork length (FL) and total weight (TW) data of S. waitei were collected at three sites from April to September 2018. A total of 1994 specimens with FL from 4.0 to 6.7 cm and TW from 0.2 to 2.3 g with the length-weight relationship of TW = 0.073FL3.0046 (R2=0.765) indicated a near isometric and positive allometric growth in the water region. The relative condition factor (Kn) ranged from 1.01 to 1.02, indicating an estimate of good condition of the fishes. The growth parameters based on von Bertalanffy was 6.56 cm (L?) with the growth coefficient (K) of 0.34 yr-1 and t0 (anchovy age at zero length ) of 0.6506. The total mortality (Z), natural mortality (F), and catch mortality (M) of S. waitei were 0.64, 1.39, and 0.75 yr-1 respectively, which suggest that the fishing activities of S. waitei are still in normal intensity. The recruitment pattern of S. waitei was stable between April and August with its peak in June by 14.21%. The fishing activities may then be limited during the spawning months (May to June) of S. waitei to maintain their population in the Strait of Malacca.

Estimation of Population Parameters and Stock Assessment of Mastacembelus armatus in the Taojiang River, Xinfeng County, Jiangxi Province, China

2019 ◽  
Author(s):  
Wu Bin ◽  
Wang Haihua ◽  
Ma Benhe ◽  
Xu Xiandong ◽  
Zeng Qingxiang
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Landing Site ◽  
Jiangxi Province ◽  
Recruitment Pattern ◽  
Growth Coefficient ◽  
Exploitation Rate ◽  
Mastacembelus Armatus ◽  
River Fish

A study was conducted to investigate the growth parameters, mortality and recruitment pattern of Mastacembelus armatus collected in the Taojiang River fish landing site, Xinfeng County. M. armatus were collected from March, 2018 to February, 2019. Growth parameters, asymptotic length (L¥) = 58.8cm and growth coefficient (k) = 0.13 year-1. Growth performance index(Ø2 ) =2.65, total mortality (Z) = 0.75 year-1, natural mortality (M) = 0.32 year-1, fishing mortality (F) = 0.43 year-1 and exploitation rate (E) = 0.57year-1.The estimated exploitation rate (E) has slightly exceeded the optimum value of E indicating this species was over exploited mainly due to fishing in the study area. The exploitation ratios were computed as Emax= 0.59, E10= 0.45, E50= 0.31. The length at first capture at 50%, (Lc) was 19.51 cm. The Steady biomass also increased with length class until 36.0-36.9 cm and the total steady state biomass was found to be 19.12 tons.

scholarly journals New insights on European hake biology and population dynamics from a sustained tagging effort in the Bay of Biscay

2013 ◽  
Vol 70 (7) ◽  
pp. 1416-1428 ◽  
Author(s):  
Hélène de Pontual ◽  
Aurélie Jolivet ◽  
François Garren ◽  
Michel Bertignac
Keyword(s):  
Population Dynamics ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Bay Of Biscay ◽  
Fishing Mortality ◽  
Return Rates ◽  
Life Traits ◽  
Species Analysis ◽  
First Maturity ◽  
European Hake

Abstractde Pontual, H., Jolivet, A., Garren, F., and Bertignac, M. 2013. New insights on European hake biology and population dynamics from a sustained tagging effort in the Bay of Biscay. – ICES Journal of Marine Science, 70: . Following a pilot experiment that fundamentally challenged the knowledge of European hake life traits (growth and age at first maturity), a sustained tagging effort was carried out in the Bay of Biscay from 2004 to 2007. Out of 27 690 fish tagged between 2002 and 2007, 1199 (4.3%) have been recovered to date. These data have permitted a refinement of the growth parameters of the species, analysis of interannual variability, improved understanding of movements and migrations, and an examination of natural (M) and fishing mortality (F). Both L∞ and K of a von Bertalanffy growth model could be estimated using a robust non-linear regression procedure. Growth varied significantly between years, which is likely related to variation in environmental factors such as temperature. Data did not reveal seasonal movements of fish perhaps because of poor tag return rates from offshore fleets. However, results clearly revealed homing behaviour and/or inshore residency. Confounding factors hindered the estimation of mortality, which resulted in high estimates of M. The outcomes of this experiment led to substantial changes in the stock assessment conducted by ICES and call into question the findings of previous studies that have used erroneous age-based data to address topics on the ecology and dynamics of this species.

scholarly journals Estimation of Growth and Mortality Parameters for Two Penaeid Species of Tanzanian Coastal Waters

2019 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Coastal Waters ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Commercial Fishing ◽  
Recruitment Pattern ◽  
Growth Coefficient ◽  
Fenneropenaeus Indicus ◽  
Asymptotic Size ◽  
Metapenaeus Monoceros ◽  
Exploitation Rate

Assessment of the growth and mortality parameters of Fenneropenaeus indicus and Metapenaeus monoceros was conducted. Samples for the study were collected during two ship surveys conducted in February and June 2011 and from land-based surveys on two sites at Bagamoyo and Nyamisati, which was conducted between February 2011 and December 2012. Lengthbased stock assessment FiSAT II software package was used for assessment. The growth parameters which were asymptotic size (L∞), growth coefficient (K), total (Z) and natural (M) mortality, exploitation rate (E) and recruitment pattern were estimated. The results of analysis indicate that asymptotic size (L∞) for F. indicus was 44.1 mm CL for zone 1, zone 2 and Bagamoyo while Nyamisati was 48.3 mm CL. The growth coefficient (K) was 0.42, 0.83, 0.3 and 0.65 per year for zone 1, zone 2, Bagamoyo and Nyamisati respectively. The natural mortality (M) value was low in Bagamoyo and high in zone 2 while exploitation rate (E) and was high at Nyamisati area and low at Bagamoyo site. The study observed high exploitation levels on the two land-based sites (Bagamoyo and Nyamisati) despite the existing moratorium on prawn commercial fishing activities since 2008 hence seasonal closure for artisanal fishers was recommended.

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