scholarly journals Population dynamics of the mullet fish, Rhinomugil corsula (Hamilton, 1822), in the Sitakunda coast of the Bay of Bengal

2019 ◽  
Vol 47 (2) ◽  
pp. 305-314 ◽  
Author(s):  
Syeda Ismat Ara ◽  
MA Azadi ◽  
Munira Nasiruddin ◽  
Aftab Hossain ◽  
MG Mustafa
Keyword(s):  
Population Dynamics ◽  
Bay Of Bengal ◽  
Relative Yield ◽  
Total Mortality ◽  
Recruitment Pattern ◽  
Instantaneous Rate ◽  
A Minor ◽  
Two Peaks ◽  
Yield Per Recruit ◽  
Rhinomugil Corsula

Population dynamics of the mullet species, Rhinomugil corsula, was studied, using FiSAT-II program, with the length-frequency data of 2480 fish specimens. The asymptotic length (L∞) and growth coefficient (K) of this fish were estimated to be 31.4 cm and 1.0/year, respectively. The instantaneous rate of natural mortality (M), fishing mortality (F) and total mortality (Z) were estimated to be 1.73, 1.20 and 2.93, respectively. The recruitment pattern of the species was prolonged with two peaks, major peak during June to December and a minor peak during January to April. The L25, L50 and L75 were found to be 8.61, 10.42 and 12.23 cm, respectively. The relative yield per recruit (Yʹ/R) and biomass per recruit (Bʹ/R) were 0.751 and 1.731, respectively. The value of exploitation (E) was found to be 0.41 which indicated that R. corsula was not over fished (E > 0.50) in the study area. The maximum exploitation (Emax) value was 0.55. The growth performance index (ϕ´ = 2.99) of R. corsula in the Sitakunda coast of the Bay of Bengal was found to be moderate. Bangladesh J. Zool. 47(2): 305-314, 2019

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.

scholarly journals Population dynamics of notopterus notopterus (Pallas, 1769) from the Kaptai reservoir of Bangladesh

2015 ◽  
Vol 12 (2) ◽  
pp. 112-122 ◽  
Author(s):  
M Golam Mustafa ◽  
S Singha ◽  
MR Islam ◽  
Nayan Mallick
Keyword(s):  
Population Analysis ◽  
Relative Yield ◽  
Total Mortality ◽  
Natural Mortality ◽  
Total Catch ◽  
Instantaneous Rate ◽  
Virtual Population ◽  
Exploitation Rate ◽  
Two Peaks ◽  
Notopterus Notopterus

Population parameters of Notopterus notopterus (Pallas, 1769) from length-frequency data collected from Kaptai Reservoir of Rangamati, Bangladesh from January, 2013 to December, 2013 were calculated by using FiSAT software. The asymptotic total length (L?) and growth coefficient (K) were estimated to be 34.91cm and 0.38 y?1respectively. The instantaneous rate of natural mortality (M), fishing mortality (F) and total mortality (Z) were estimated to be as 0.91 y?1, 0.28 y?1and 1.19 y?1 respectively. The value of exploitation rate (E) was found to be 0.24 which clearly pointed toward moderate or less fishing pressure (E<0.50) of N. notopterus in the Kaptai reservoir of Bangladesh. The recruitment of the species was found throughout the year with two peaks - one from March-April; and another from May- June. Virtual population analysis (VPA) estimated that the maximum numbers of N. notopterus were caught between 10.50 cm to 32.50 cm with maximum F value (0.80 y?1) in the mid length of 18.30 cm. During the year 2013 the total catch of N. notopterus was found to be 664.5 MT, which contributed about 7.78% of the total catch of Kaptai Lake. Relative yield per recruit (Y’/R) and biomass per recruit (B’/R) suggested that the natural mortality should be reduced to 0.91 y?1 by proper management to obtain a maximum sustainable exploitation rate (Emax= 0.828) for the species in the reservoir. DOI: http://dx.doi.org/10.3329/sja.v12i2.21923 SAARC J. Agri., 12(2): 112-122 (2014

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.

scholarly journals GROWTH AND EXPLOITATION STATUS (Channa striata Bloch, 1793) IN LUBUK LAMPAM FLOODPLAINS, SOUTH SUMATERA

2013 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Zulkarnaen Fahmi ◽  
Syarifah Nurdawati ◽  
Freddy Supriyadi
Keyword(s):  
Relative Yield ◽  
Total Mortality ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Population Parameters ◽  
Future Plan ◽  
Channa Striata ◽  
Exploitation Status ◽  
Yield Per Recruit

Due to the economic importance of C. striata in Lubuk Lampam floodplains (Indonesia), this study is aimed to estimate the biological and population parameters required for proposing a future plan to sustain and manage this valuable fish resource. The growth, mortality and explotation ratio of <em>Channa striata</em> estimated by employing FiSATProgramme are reported. The parameters of Von Bertalanffy growth model of 1,529 sample fishes were estimated as K= 0.36/ year, L” = 72.98 cm and to = -0.52 year. The coefficients of total mortality (Z), natural mortality (M) and fishing mortality (F) were 1.72, 0.73 and 0.99 year-1 respectively. Relative yield per recruit analysis shows that the presentexploitation rate (E) was 0.58. Yield per recruit can be maximized at the exploitation ratio of 0.5 and Lc/Linf values of 0.3. The Yield per recruit and biomass per recruit models indicated that, the fisheries status of <em>C. striata</em> in Lubuk Lampam floodplains exceed the limit reference point (Fmax), thus stock of this species in Lubuk Lampam floodplains is indicated being driving down.Reduction in fishing effort and increase number of selective fishing gears are suggested to sustain the fishery of <em>Channa striata</em> in Lubuk Lampam floodplains.

scholarly journals Population Dynamics of Five Important Commercial Fish Species in the Sundarbans Ecosystem of Bangladesh

2019 ◽  
pp. 1-13
Author(s):  
Md. Golam Mustafa ◽  
Imran Ahmed ◽  
Mohammod Ilyas
Keyword(s):  
Population Dynamics ◽  
Fish Species ◽  
Total Mortality ◽  
Assessment Tools ◽  
Natural Mortality ◽  
Lates Calcarifer ◽  
Recruitment Pattern ◽  
Exploitation Rate ◽  
Acanthopagrus Latus ◽  
The Sundarbans

Aims: To determine the population dynamics and assess the exploitation level of Mystus gulio, Acanthopagrus latus, Chelon parsia, Otolithoides pama and Lates calcarifer in the Sundarbans ecosystem of Bangladesh. Study Design: Monthly length-frequency data of five fish species were collected from the Sundarbans ecosystem. The lengths of five fish species were recorded to the nearest one cm intervals in each month. Place and Duration of Study: The study was conducted from January to December 2011 in the Sundarbans ecosystem in Bangladesh. Methodology: The FAO-ICLARM Fish Stock Assessment Tools (FiSAT II) software was used to estimate the von Bertalanffy growth parameters (L∝ and K), mortality coefficients (Z, M and F), probability of capture, recruitment pattern and Yield/Biomass-per-recruit for five commercially important fish species caught by fishers in the Sundarbans ecosystem of Bangladesh. Results: In the Sundarbans ecosystem of Bangladesh area the values of asymptotic length (L∝) for Mystus gulio, Acanthopagrus latus, Chelon parsia, Otolithoides pama and Lates calcarifer were found to be 23.0 cm, 33.6 cm, 30.0 cm, 32.5 cm and 55.0 cm respectively while the growth co-efficient (K) were 0.75, 0.85, 1.1, 0.8 and 0.5 respectively. The estimates for L∝ (23.00 – 55.0 cm) and K (0.5-1.1 year-1) obtained were consistent with those available in the literature. Relatively high K and low L∝ values, typical of short-lived tropical fishes, were obtained for Mystus gulio, Acanthopagrus latus, Chelon parsia and Otolithoides pama. The length growth performance index (ϕ’) of the Pauly and Munro’s function was in the range of 2.599 – 3.180. Natural mortality, fishing mortality and total mortality were in the range of 0.956-1.89, 0.55-1.58 and 1.52-3.3 respectively. Estimates for total mortality (Z) and natural mortality (M) imply low annual rates of survival and high turnover rates. The recruitment pattern suggested one main pulse of annual recruitment. The exploitation rate was estimated to be between 27% and 47% and the length at first capture was estimated to be approximately 19-54% of L∝. The exploitation rate obtained for five fish species are relatively lower compared to other available studies in the coastal areas of Bangladesh. The growth and exploitation rates obtained were compared with available estimates to evaluate the consistency of the results with current knowledge about the species in the region. Conclusion: The study indicated that the length-at-first-capture/L∝ seem to be a simple parameter, which could be used to make a rapid assessment of the status of the stocks. All together, the present study reveals that the population of these five studied species attains acceptable sustainability levels in the Sundarbans ecosystem and scope for a slight increase in catch efforts.

scholarly journals Population Dynamics of Two Cichlids, Oreochromis aureus and Tilapia zilIi, from Wadi EI-Raiyan Lakes, Egypt

2004 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
S.F. Mehanna
Keyword(s):  
Population Dynamics ◽  
Relative Yield ◽  
Von Bertalanffy ◽  
Fishing Mortality ◽  
Oreochromis Aureus ◽  
Exploitation Rate ◽  
Growth Equations ◽  
Yield Per Recruit

Age, growth, mortality, relative yield-per-recruit and relative biomass-per-recruit of Oreochromis aureus and Tilapia zilli collected from Wadi EI-Raiyan lakes during the period from August 2000 until July 2001 have been estimated. Age was determined from scale readings and the results showed that the maximum life spans of O. aureus and T. zilli were three and four years, respectively. The von Bertalanffy growth equations were L1= 27.15 (l-e'0.56(t+0.32) for 0. aureus and L1= 33.5 (l-e -0.49(t+0.15) for T. zilli. The instantaneous annual rates of total, natural and fishing mortality were calculated as 1.69, 0.25 and 1.44, respectively for 0. aureus and 1.1, 0.2 and 0.9, respectively for T. zilli. Exploitation rate was estimated as 0.85 and 0.82 for 0. aureus and T. zilli, respectively. Relative yield-per- recruit and relative biomass-per-recruit analysis indicated that the stocks of O. aureus and T. zilli were overexploited and that the current exploitation rate should be reduced by about 53% for 0. aureus and 55% for T. zilli to ensure that at least 50% of the individuals could be maintained for spawning and recruitment.  

scholarly journals Population dynamics of the cyprinid fish, Amblypharyngodon mola (Hamilton) from the Kaptai lake, Bangladesh

2013 ◽  
pp. 141-151 ◽  
Author(s):  
MA Azadi ◽  
A Mamun
Keyword(s):  
Population Dynamics ◽  
Growth Parameters ◽  
Population Analysis ◽  
Maximum Yield ◽  
Water Reservoir ◽  
Total Mortality ◽  
Cyprinid Fish ◽  
Virtual Population ◽  
Computer Based ◽  
Yield Per Recruit

Length frequency based population dynamics of the small indigenous cyprinid fish, Amblypharyngodon mola from the Kaptai lake (an artificial water reservoir), Bangladesh were studied using the computer based FiSAT program. Growth parameters La and K were found to be 104.65 mm and 0.95 year-1 respectively. The annual rate of natural mortality (M), fishing mortality (F) and total mortality (Z) were found to be 1.22, 2.04 and 3.26 respectively. Exploitation rate (E) was 0.63, while maximum yield per-recruit (Emax) was estimated as 0.678. The suitable selection pattern (L50) was found to be 51.09 mm. The yield per recruit and biomass per recruit determined as a function of Lc/La and M/K were estimated as 0.49 and 1.28 respectively. The Wetherall plot provided estimates of La and Z/K were 103.38 mm and 3.31 respectively. Growth performance index (?? = 4.017) was found to be suitable. Virtual population analysis (VPA) showed that the maximum number of A. mola was caught between the total length of 75 to 93 mm with values of F exceeding to 2.04 year-1. The estimated mean biomass was found to be 2.81 metric tons. The fish was recruited in the fishery during March to October with maximum in July. DOI: http://dx.doi.org/10.3329/cujbs.v4i1.13398 The Chittagong Univ. J. B. Sci.,Vol. 4(1&2):141-151, 2009

scholarly journals Dynamique De La Population De La Crevette D’eau Douce Atya Scabra (Leach, 1815) (Decapoda: Atyidae) Dans La Rivière Bia, Région Du Sud-Comoé (Côte d’Ivoire)

2017 ◽  
Vol 13 (12) ◽  
pp. 84
Author(s):  
Vincent Kadjo ◽  
Assoi O. Etchian ◽  
Jean-Noel Yapi ◽  
Atcho Otchoumou ◽  
Aka Jean-Paul Agnissan ◽  
...  
Keyword(s):  
Survival Rate ◽  
Growth Performance ◽  
Normal Distribution ◽  
Performance Index ◽  
Total Mortality ◽  
Major Peak ◽  
Minor Peak ◽  
Rational Management ◽  
A Minor ◽  
Two Peaks

The parameters of growth, mortality, the exploitation and the recruitment of Atya scabra (Leach, 1815) as traditionally fished in the Bia river, were studied. These parameters were determined from the size frequencies by the FiSAT II software. The results obtained at the specimens of Aboisso were:= 156,45 mm, K = 1,50 year -1, Φ' = 4,56, Z = 5,72 year -1, M = 1,48 year -1, F = 4,24 year -1 and E = 0,74 year -1. In Biaka, theestimated values were: L = 140,7 mm, K = 0,68 year -1, Φ' = 4,13, Z = 1,52year -1, M = 0,91 year -1, F = 0,61 year -1 and E = 0,40 year -1 . Aboisso specimens have a higher growth performance index (Φ') than Biaka's and a weak longevity (tmax = 2 years) compared to Biaka (tmax = 4.41 years). Shrimps are under exploited in the locality of Biaka (E 0.5). Total mortality is higher in Aboisso than in Biaka. However, the survival rate recorded in Aboisso (S = 0.003 years) is lower than that of Biaka (S = 0.22 years). Recruitment is continuous throughout the year, with two peaks (a major peak in September and a minor peak in February) in Aboisso. As for Biaka, the presence of a normal distribution indicates that recruitment is single. These results will serve as a database for rational management of A. scabra.

scholarly journals Population dynamics and stock assessment of grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-west coast of India

2017 ◽  
Vol 64 (3) ◽  
Author(s):  
G. B. Purushottama ◽  
Gyanaranjan Dash ◽  
Thakur Das ◽  
K. V. Akhilesh ◽  
Shoba Joe Kizhakudan ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Stock Assessment ◽  
Total Mortality ◽  
North West ◽  
The North ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Yield Per Recruit ◽  
Peak Phase

The life history and exploitation parameters of Rhizoprionodon oligolinx Springer, 1964 were assessed using commercial landing data of 2012-2015 from Mumbai waters of India to understand the population dynamics and stock status of the species. The average annual landing of the species was estimated to be 383 t, which formed about 9.1% of the total shark landings of Maharashtra. L∞, K and t0 estimated were 97.1 cm, 0.47 yr-1 and -0.79 yr respectively. Total mortality (Z), fishing mortality (F) and natural mortality (M) rates were estimated as 2.16 yr-1, 1.48 yr-1 and 0.69 yr-1 respectively. The length at capture (L50), length at female maturity (Lm50) and male maturity (Lm50) were estimated as 49.7, 62.3 and 59.5 cm respectively, which indicated that most of the sharks entered peak phase of exploitation before attaining sexual maturity. Length-weight relationship indicated allometric growth (b>3) for the species. The species was found to be a continuous breeder and showed peak recruitment during April. The current exploitation rate (Ecur) was found to be 0.68, which is lower than Emax estimated for the species using Beverton and Holt yield per recruit analysis. Thompson and Bell prediction model showed that at current exploitation level, the biomass (B) has reduced to 32% of virgin biomass (B0) where as, the spawning stock biomass (SSB) has reduced to 16% of the virgin spawning stock biomass (SSB0). Hence the exploitation level for the species should be reduced by 40% that will ensure the availability of SSB at a relatively safer 30% level to rebuild the stock for long term sustainability of the resource.

scholarly journals Aspects of Population Dynamics of Tiger Tooth Croaker, Otolithes ruber (Bloch and Schneider, 1801) from Northwest Arabian Gulf, Iraq

2021 ◽  
pp. 9-21
Author(s):  
Abdul-Razak M. Mohamed ◽  
Ali H. Al-Hassani
Keyword(s):  
Population Dynamics ◽  
Population Analysis ◽  
Arabian Gulf ◽  
Relative Yield ◽  
Total Mortality ◽  
Reference Points ◽  
Virtual Population Analysis ◽  
Virtual Population ◽  
Exploitation Rate ◽  
Otolithes Ruber

The present study consists of the growth, mortality, relative yield recruit and virtual population analysis of tigertooth croaker, Otolithes ruber from Iraqi marine waters, northwest Arabian Gulf between February 2020 and January 2021. Analysis of population dynamics employed methods fitted in FiSAT II software using pooled length-frequencies. A total of 3835 individuals of O. ruber ranged from 17.0 to 60.0 cm have been collected. The exponent (b) of the length-weight relationship was found to be 2.755. The von Bertalanffy growth parameters (L∞ and K) were estimated as 68.5 cm and 0.36, respectively, while the growth performance index (Ø') was 3.228.  The total mortality (Z) was calculated as 1.10, while the natural and fishing mortality rates were 0.69 and 0.41, respectively, and the current exploitation rate (Ecurrent) was 0.38. Fish were recruited to the fishery at a mean size of L50= 20.55 cm. The recruitment pattern of O. ruber was continuous throughout the year with two major peaks. The analysis of yield-per-recruit (Y/R’) indicates that the current exploitation rate was below the biological target reference points (E0.1 = 0.40 and Emax= 0.53), refer to the stock of O. ruber is underexploited. The 27 cm length group was more vulnerable to fishing and more harvested according to virtual population analysis. sLength at first capture was higher than the length at first maturity of the species in the region. For management purposes, more yields could be obtained by increasing the mesh sizes of the nets employed in the fishing of the species. 

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