scholarly journals Growth, Mortality and Yield-per-recruit of Nile Tilapia (Oreochromis niloticusM/em>) in Garmat Ali River, Iraq

2020 ◽  
Vol 8 (6) ◽  
Author(s):  
Ayat N. Salman ◽  
Abdul-Razak M Mohamed
Keyword(s):  
Assessment Tool ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Reference Points ◽  
Fishing Mortality ◽  
Exploitation Rate ◽  
Biological Target ◽  
Mean Size ◽  
Yield Per Recruit

The study was conducted to estimate the growth, mortality, recruitment and yield-per-recruit of Oreochromis niloticus from Garmat Ali River, Basrah, Iraq from October 2019 to September 2020. The population parameters were analyzed using the FAO-ICLARM stock assessment tool (FiSAT). A total of 2696 O. niloticus ranged from 7.0 to 25.0 cm and the sizes 13.0-18.0 cm constituted 64.2% of the total catch. The length-weight relationship was W= 0.012L3.109 suggesting that the species shows positive allometric growth. The growth parameters for the species were estimated as L∞= 30.45 cm, K= 0.45, to= -0.313 and Ǿ= 2.622. The coefficients of total mortality (Z), natural mortality (M) and fishing mortality (F) were 3.26, 1.03 and 2.24, respectively. The exploitation rate for the species computed to be 0.69. Fish were recruited to the fishery at a mean size of L50= 14.92 cm. The peak of recruitment was 23.51% in June. The analysis of yield-per-recruit (Y/R’) indicates that stock is not being overfished since the present exploitation rate was below the biological target reference points (E0.1 and Emax). So, more yields could be achieved by reducing the mesh sizes of the nets for fishing the species

scholarly journals Population dynamics of Chrysichthys nigrodigitatus (Lacépède, 1803) in Ikere-gorge, Oyo State, Nigeria

2021 ◽  
Vol 56 (1) ◽  
pp. 79-86
Author(s):  
S.O. Ajagbe ◽  
D.O. Odulate ◽  
R.O. Ajagbe ◽  
O.S. Ariwoola ◽  
F.I. Abdulazeez ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Fishing Mortality ◽  
Length Frequency ◽  
Optimum Length ◽  
Growth Coefficient ◽  
Exploitation Rate ◽  
Length Frequency Data

The growth and mortality parameters of Chrysichthys nigrodigitatus were estimated to assess the sustainability of its exploitation in Ikere-gorge, Oyo State, Nigeria. A total of 1210 of Chrys­ichthys nigrodigitatus were sampled from fishermen catches between January, 2017 and Decem­ber, 2018. C. nigrodigitatus were exploited with gillnet, cast net and traps (Malian trap net and bamboo). Total lengths were measured with fish measuring board. The FAO-ICLARM Stock Assessment Tool (FiSAT II) software was used to analyze length-frequency data of the fish. The estimated growth parameters are: asymptotic length is 60.9 cm, growth coefficient is 0.96, optimum length is 38.51 cm; length at maturity is 33.44 cm while length-at-first-capture is 12.62 cm. The estimated mortality parameters are: total mortality is 3.29 per year, natural mortality is 1.43 per year and fishing mortality is 1.86. It was observed that C. nigrodigitatus of Ikere-gorge were more vulnerable to exploitation at sizes less than their length at maturity. Likewise, the ex­ploitation rate (E = 0.57 yr-1) is greater than sustainable exploitation rate (Emax = 0.46 yr-1). This shows that exploitation of C. nigrodigitatus in Ikere-gorge is not sustainable. Therefore, there is need to reduce fishing pressure on C. nigrodigitatus to ensure its sustainability in Ikere-gorge.

scholarly journals Population dynamics and management of two cichlid species in the Shatt Al-Arab River, Iraq

2020 ◽  
Vol 12 (2) ◽  
pp. 261-269
Author(s):  
Abdul-Razak M. Mohamed ◽  
Abdullah N. Abood
Keyword(s):  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Reference Points ◽  
Invasive Fish ◽  
Oreochromis Aureus ◽  
Cichlid Species ◽  
Assessment Study ◽  
Biological Target ◽  
Yield Per Recruit

Cichlids are invasive fish to Iraqi waters and became well established and prevailing in different waters. Despite that, there is no stock assessment study conducted for these fish. So, growth, mortality, recruitment and yield-per-recruit of two cichlid’s species; Coptodon zillii and Oreochromis aureus from the Shatt Al-Arab River, Iraq were evaluated from November 2015 to October 2016 using the FiSAT software. A total of 1285 C. zillii (2.9-24.0 cm TL) and 1353 O. aureus (4.5-25.0 cm TL) were examined. Length-weight relationships were derived, indicating allometric growth for both species. The growth parameters (L?, K, Rn, to and ?) obtained for C. zillii were 25.5 cm, 0.320, 0.212, -0.793 and 2.318, respectively, while for O. aureus were 27.8, 0.490, 0.214, -0.271 and 2.578, respectively. The annual rate of total mortality (Z), fishing (F) and natural (M) for C. zillii was found to be 1.51, 0.84 and 0.68 respectively, and for O. aureus 2.49, 1.08 and 1.41, respectively. The present exploitation rates (Epresent) for C. zillii and O. aureus were computed to be 0.454 and 0.57, respectively. Lengths at first capture (LC) were 12.97 cm for C. zillii and 13.25 cm for O. aureus. The peaks of recruitment of C. zillii and O. aureus were from February to May and May to July, respectively. The Epresent for C. zillii and O. aureus were below the biological target reference points (F0.1  and Fmax), indicating that these species were not overexploited. For management purposes, more yields could be obtained by an increase in the fishing activities on cichlids.

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 Growth, mortality and stock assessment of greenback mullet, Planiliza subviridis from northwest Arabian Gulf, Iraq

2021 ◽  
Vol 6 (2) ◽  
pp. 142-148
Author(s):  
Abdul-Razak M. Mohamed ◽  
Ali H. Al-Hassani
Keyword(s):  
Mortality Rate ◽  
Stock Assessment ◽  
Population Analysis ◽  
Arabian Gulf ◽  
Total Mortality ◽  
Reference Points ◽  
Fishing Mortality ◽  
Fish Samples ◽  
Exploitation Rate ◽  
First Maturity

The growth, mortality and stock parameters of greenback mullet, Planiliza subviridis from Iraqi marine waters, northwest Arabian Gulf was assessed using FiSAT II software for length-frequency data collected from February 2020 to January 2021. P. subviridis is one of the species caught in large quantities as commercial by artisanal fishers. Fish samples were collected by the Shaheen steel-hulled dhow and from the artisanal fishermen. The total length and body weight relationship of fish was estimated as W= 0.034L2.670, indicating negative allometric growth. Of 3350 specimens, growth and mortality parameters were evaluated. The asymptotic length (L∞), growth rate (K) and growth performance index (Ø') were 33.8 cm, 0.30 and 2.535, respectively. The total mortality rate (Z), natural mortality rate (M), and fishing mortality rate (F) were 1.11, 0.74 and 0.38, respectively. The present exploitation rate (Epresent) of P. subviridis computed as 0.34. Length at first capture (L50) was 17.47 cm. Recruitment of P. subviridis was observed throughout the year, with a peak during July. The yield per recruit analysis indicates that the current exploitation rate was below the biological target reference points (E0.1 and Emax), which refers to the stock of P. subviridis is underexploited. Virtual population analysis results showed that mid-lengths (16-22 cm) experienced the highest fishing mortality. The length at first capture (L50) was higher than the length at first maturity (Lm) of the species. So, for management purposes, more yields could be obtained by increasing the fishing activities on this species for a substantial harvest.

scholarly journals Population dynamics of an invasive species Carassius auratus in the Shatt Al-Arab River, Iraq

2020 ◽  
Vol 5 (3) ◽  
pp. 384-389
Author(s):  
Abdullah N. Abood ◽  
Abdul-Razak M. Mohamed
Keyword(s):  
Population Dynamics ◽  
Carassius Auratus ◽  
Assessment Tool ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Relative Yield ◽  
Reference Points ◽  
Fish Length ◽  
Exploitation Rate ◽  
Precautionary Measures

The population dynamics of the crucian carp, Carassius auratus in the Shatt Al-Arab River, Iraq was studied from November 2015 to October 2016 with monthly samples collected by different fishing gears. The FAO-ICLARM Stock Assessment Tool (FiSAT II) software was used for the mathematical analysis. Length-weight relationship was calculated as W= 0.0149L3.065 for fish length 4.6 to 26.8 cm. Growth parameters L∞, K and Ø were computed as 29.1 cm, 0.51 and 2.635. The total (Z), natural (M) and fishing (F) mortalities were 2.69, 1.09 and 1.60, respectively. Exploitation rate (E) was 0.59. Length at first capture (Lc) was found to be 10.04 cm. C. auratus displayed one main pulse of annual recruitment. The relative yield per recruit analysis revealed that the exploitation rate (E) of C. auratus was higher than the biological target reference points E0.1 and equivalent to Emax. It could be concluded that the C. auratus stock in the Shatt Al-Arab River is operating nearby the exploited situation and needs some precautionary measures to avoid the overexploitation by activating the national law of fishing, exploiting and protecting aquatic resources, in particular preventing illegal fishing methods and follow up the execution of the closed season to prevent the decline of our fish resources.

Population dynamics and stock assessment of deep water rose shrimp Parapenaeus longirostris (Lucas, 1846) from the Mediterranean Coast of Morocco

2020 ◽  
Vol 67 (2) ◽  
Author(s):  
Hesham Awadh ◽  
Mustapha Aksissou
Keyword(s):  
Population Dynamics ◽  
Deep Water ◽  
Growth Parameters ◽  
Stock Assessment ◽  
Total Mortality ◽  
Mediterranean Coast ◽  
Parapenaeus Longirostris ◽  
Exploitation Rate ◽  
The Mediterranean ◽  
Yield Per Recruit

The population dynamics and stock parameters of the deep water rose shrimp Parapenaeus longirostris (Lucas, 1846) was investigated from the Mediterranean coast of Morocco. Length-frequency data were collected from landings of coastal trawlers at M’diq Port on the Moroccan Mediterranean coast over a period of 13 months from April 2017 to April 2018. The estimated growth parameters were CL∞ = 52.87 mm, K = 0.39 yr-1 and to = - 0.35 .Total mortality coefficient (Z) was estimated as 3.49 yr-1 while the natural mortality estimated using two different methods was 1.89 yr-1 and 1.36 yr-1 and correspondingly the fishing mortality was calculated as 1.51 yr-1 and 2.13 yr-1. Yield per recruit and relative biomass per recruit analysis showed that the value of current exploitation rate (E) is 0.68 which is higher than the exploitation rate E 0.5=0.36, which indicates that the stock is currently overexploited. Hence it is advised to decrease the present exploitation rate by 50% of the current level to sustain the fishery.

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.  

scholarly journals Population parameters of the pontic shad, Alosa immaculata Bennett, 1835 in the Fatsa coast of the south-eastern Black Sea

2019 ◽  
Vol 36 (4) ◽  
pp. 319-324
Author(s):  
İsmet Balık
Keyword(s):  
Black Sea ◽  
Maximum Yield ◽  
Total Mortality ◽  
Reference Points ◽  
Growth Equation ◽  
Fishing Mortality ◽  
Population Parameters ◽  
The South ◽  
South Eastern ◽  
Exploitation Rate

The aim of this study is to estimate population parameters of pontic shad, Alosa immaculata Bennett, 1835 in the Fatsa coast of the south-eastern Black Sea. A total of 314 pontic shad specimens were collected from study area using artisanal fishing gears from March 2013 to February 2014. In the study, parameters of the von Bertalanffy growth equation were found as L∞=43.05 cm; k=0.430 per year and t0=-0.451 year. The growth performance index (Φ') was estimated as 2.90. The total mortality (Z), natural mortality (M), fishing mortality rates (F) were calculated as 1.33 year-1, 0.75 year-1 and 0.58 year-1, respectively. The annual instantaneous fishing mortality rate was greater than both the target (Fopt=0.375 year-1) and limit (Flimit=0.50 year-1) biological reference points. Similarly, the present level of exploitation rate (E=0.43) was higher than the exploitation ratio for maximum yield per recruit (Emax=0.375) suggesting that overexploitation occurred. These results showed that this species has been over-exploited in the Fatsa coast of the south-eastern Black Sea. Measures should be taken to reduce the current exploitation rate for sustainable fishing of pontic shad in the Fatsa coast of the south-eastern Black Sea.

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

scholarly journals PARAMETER POPULASI IKAN BETOK (Anabas testudineus (BLOCH, 1792)) DI EKOSISTEM PAPARAN BANJIR SUNGAI MUSI, Lubuk Lampam

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Syarifah Nurdawati ◽  
Zulkarnaen Fahmi ◽  
Freddy Supriyadi
Keyword(s):  
Growth Parameters ◽  
Total Mortality ◽  
Fish Length ◽  
Fishing Mortality ◽  
Anabas Testudineus ◽  
Weight Growth ◽  
Exploitation Rate ◽  
Management Policies ◽  
Distribution Of Fish ◽  
Musi River

Anabas testudineus Bloch, 1792 is economically important fish species found in Lubuk Lampam floodplains of Musi River. Fishing activities that take place throughout the year can affect reproduction patterns and recruitment (new additions) of fish. This study aims to evaluate several parameters of betok fish populations that can be used as input for fish resource management policies in floodplains of Musi river. A total of 3271 samples of betok fish caught by fishermen from March to November 2011 were collected to obtain data on fish length and weight. Growth parameters (L∞, K, Z dan M) were calculated using FiSAT II based on the length frequency distribution of fish. The values of L∞ and K were obtained at 204.75 mm and 0.24 / year respectively while the maximum age of fish was estimated to be 4.36 years. The total mortality (Z) and natural mortality (M) of betok fish is 0.99 / year and 0.42 / year, Fishing mortality (0.56/year). The exploitation rate (0.57) was slightly lower than the predicted value (Emax= 0.69) indicating that Anabas  testudineus was near fully exploited in the Lubuk Lampam floodplain ecosystem.  

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