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This study focused on identification phytoplankton, zooplankton, benthos, fishes and relationship between biotic and abiotic parameters at three stations in the Kan river during 2014. This study identified 19 phytoplankton taxa. The findings showed, the diatoms abundance were dominated in the river. The chlorophytes abundance were recorded the lowest abundance in this study. The nutrients and water temperature were the significant abiotic parameters to increase cyanophytes and chlorophytes abundance in the Kan river. This study identified 26 zooplankton taxa. The Rotatoria and Protozoa abundance were dominated in the Kan river. Based on CCA, there was no correlation between abundance zooplankton and abiotic parameters. The biodiversity index of plankton was between 1.8 and 2 and the lake situation is located in the mesotrophic category. The study of the Kan river fishes showed, only one endemic fish species Capoeta bohsei. The length (between 38 and 270 mm, average 144±86 mm) and weight (between 1.1 and 356 g, average 108.8±146.7 g) of the C. bohsei were varied during the study period. The 19 benthos taxa were identified. The Ephemeroptera was most abundant in the benthos groups. The classification of river based on biology indicator and environmental parameters confimed that water quality is located in the moderate category. Iranian Fisheries Science Research Institute Published

This study focused on identification phytoplankton, zooplankton, benthos, fishes and relationship between biotic and abiotic parameters at three stations in the Kan river during 2014. This study identified 19 phytoplankton taxa. The findings showed, the diatoms abundance were dominated in the river. The chlorophytes abundance were recorded the lowest abundance in this study. The nutrients and water temperature were the significant abiotic parameters to increase cyanophytes and chlorophytes abundance in the Kan river. This study identified 26 zooplankton taxa. The Rotatoria and Protozoa abundance were dominated in the Kan river. Based on CCA, there was no correlation between abundance zooplankton and abiotic parameters. The biodiversity index of plankton was between 1.8 and 2 and the lake situation is located in the mesotrophic category. The study of the Kan river fishes showed, only one endemic fish species Capoeta bohsei. The length (between 38 and 270 mm, average 144±86 mm) and weight (between 1.1 and 356 g, average 108.8±146.7 g) of the C. bohsei were varied during the study period. The 19 benthos taxa were identified. The Ephemeroptera was most abundant in the benthos groups. The classification of river based on biology indicator and environmental parameters confimed that water quality is located in the moderate category.

This study was conducted to determine growth parameters, catch and fishing effort trends, stock assessment of Caspian Sea mullets in the Iranian coastal waters of Caspian Sea in the fishing season of 2013-2014. For gathering of data on biometry and catch statistics, 5 mobile working group in the regions of Anzali, Kiashahr, Noshahr, Babolsar and Torkmen were involved from the start to the end of fishing season.Gathered data Were entered to the computer. For data analysis, common methods were undertaken for estimation of growth parameters, mortality rates, biomass and Maximum Sustainable yield (MSY) as well. According to the result, the number of beach seines cooperatives was 124 and fishing efforts were 44688 beach seining haul. The catch per unit of effort CPUE) was calculated 53 kg/haul during this fishing season. The total catches of Caspian Sea mullets (including illegal fishing estimated as 2373 mt. Growth parameters of golden gray mullet (Liza aurata) were estimated as K=0.16/yr, L_∞=57.4 cm, t_0=-0.45/yr. Based on catch-at-age data, in the fishing season of 2013-2014, the total biomass, from the biomass-based cohort analysis were estimated 12473.3. mt. Based on these results, the fishing mortality rate in fishing season of 2013-2014 were 0.575/yr. In this survey, the Maximum sustainable yield were estimated as 2558.6 mt respectively. Generally from three Northern Province’s cooperatives 3406 samples collected. Results of biometry of golden gray mullet (Liza auratus) showed that the mean length and weight and age of this species were 32.3±6.1 cm and 383.5±74.823.4 g and 1.2±5.6 y respectively and leaping gray mullet (Liza saliens) showed that the mean length and weight and age of this species were 24.8±3.3 cm and 119±25.5 g and 2.5±0.6 y respectively. The biometric results showed that, 97.5% of the samples belonged to golden gray mullet and population of leaping gray mullet was sever declined. Also, the fishing of the mullet was increased over the last year by 10.3 % from 2151 tons to 2373 tons per year during 1391-92 and 1392-93, respectively .

Caspian trout (Salmo trutta caspius ) is one of the migratory fish species which lives and feeds in the Caspian Sea .This species distributed in south and western of the Caspian Sea . In order to rehabilitation of the Caspian trout in western area, the operation of the project started from the beginning of the fishing season of the 20112012. Specimens of the Caspian trout obtained from beach seine cooperatives and have been transferred to the fish farm in Asalem region .Totally, 44 specimens of the Caspian trout has been caught in two month period .Most of the fishes was from Kargan roud river . The mean length and weight of the brood fishes were 67.7 cm and 3122.7 g respectively .As at present Shilat uses just the broods of the Tonekaboon region for restocking of this species ,we recommend to use the broods of the western region separately for rehabilitation of the stocks of this region .

This study was conducted to determine growth parameters, catch and fishing effort trends, stock assessment of Caspian Sea mullets in the Iranian coastal waters of Caspian Sea in the fishing season of 2013 - 2014. For gathering of data on biometry and catch statistics, 5 mobile working group in the regions of Anzali , Kiashahr , Noshahr , Babolsar and Torkmen were involved from the start to the end of fishing season.Gathered data Were entered to the computer. For data analysis , common methods were undertaken for estimation of growth parameters , mortality rates , biomass and Maximum Sustainable yield ( MSY ) as well. . According to the result, the number of beach seines cooperatives was 124 and fishing efforts were 44688 beach seining haul . The catch per unit of effort CPUE) was calculated 53 kg/haul during this fishing season . The total catches of Caspian Sea mullets (including illegal fishingestimated as 2373 mt. Growth parameters of golden gray mullet (Liza aurata ) were estimated as K=0.16 /yr, L∞ = 57.4 cm, t0 = - 0.45 /yr. Based on catch-at-age data, in the fishing season of 2013-2014 , the total biomass, from the biomass-based cohort analysis were estimated 12473.3. mt. Based on these results , the fishing mortality rate in fishing season of 2013-2014 were 0.575 /yr . In this survey , the Maximum sustainable yield were estimated as 2558.6 mt respectively . Generally from three Northern province's cooperatives 3406 sampels collected.Results of biometry of golden gray mullet (Liza auratus) showed that the mean length and weight and age of this species were 32.3 ± 6.1 cm and 383.5 ± 74.823.4 g and 1.2 ± 5.6 y respectively and leaping gray mullet (Liza saliens) showed that the mean length and weight and age of this species were 24.8 ± 3.3 cm and 119 ± 25.5 g and 2.5 ± 0.6 y respectively . The biometric results showed that ,97.5 % of the samples belonged to golden gray mullet and population of leaping gray mullet was sever declined. Also , the fishing of the mullet was increased over the last year by 10.3 % from 2151 tones to 2373 tones per year during 1391-92 and 1392-93 , respectively . Iranian Fisheries Science Research Institute Published

Caspian trout (Salmo trutta caspius ) is one of the migratory fish species which lives and feeds in the Caspian Sea .This species distributed in south and western of the Caspian Sea . In order to rehabilitation of the Caspian trout in western area, the operation of the project started from the beginning of the fishing season of the 20112012. Specimens of the Caspian trout obtained from beach seine cooperatives and have been transferred to the fish farm in Asalem region .Totally, 44 specimens of the Caspian trout has been caught in two month period .Most of the fishes was from Kargan roud river . The mean length and weight of the brood fishes were 67.7 cm and 3122.7 g respectively .As at present Shilat uses just the broods of the Tonekaboon region for restocking of this species ,we recommend to use the broods of the western region separately for rehabilitation of the stocks of this region . Iranian Fisheries Science Research Institute Published

In the years 2007-2007, 2008-2009 and 2009-2010 the exploitation of bony fishes resources (by 131 beach seines) started on 12 October but finished on 9 April, 9 April and 13 April, respectively. During these periods the total catch of bony fishes were 23537.8, 20045.5 and 18664.8 tonnes, respevtively. During these periods, kutum predominated and represented the highest proportion of total catch at 73.1, 74.0 and 66.9% , followed by golden grey mullet at 18.3, 13.9 and 18.7%, respectively. K values calculated 0.22, 0.15 and 0.14 year-1 and L∞ were 66.0, 62.7 and 70.0 cm for kuttum, golden grey mullet and common carp, respectively. The instantaneous coefficient natural mortality were estimated as 0.386 and 0.35 year-1 for kutum and golden grey mullet, respectively. During three periods, the exploitation rates were 0.789, 0.584 and 0.614 for kutum and 0.71, 0.75 and 0.61 for golden grey mullet, respectively. In the years 2007-2007, 2008-2009 and 2009-2010, the total biomass, from the biomass-based cohort analysis were 56600, 62090 and 61590 tonnes for kutum and and MSY estimated about 24733.7 and 8550.4 tones for kuttum and 11040, 11900 and 14460 tonnes for golden grey mullet, respectively. The ABC (acceptable biological catch) were estimated as 8000 and 2200 tonnes. Iranian Fisheries Science Research Institute Published

In the years 2007-2007, 2008-2009 and 2009-2010 the exploitation of bony fishes resources (by 131 beach seines) started on 12 October but finished on 9 April, 9 April and 13 April, respectively. During these periods the total catch of bony fishes were 23537.8, 20045.5 and 18664.8 tonnes, respevtively. During these periods, kutum predominated and represented the highest proportion of total catch at 73.1, 74.0 and 66.9% , followed by golden grey mullet at 18.3, 13.9 and 18.7%, respectively. K values calculated 0.22, 0.15 and 0.14 year-1 and L∞ were 66.0, 62.7 and 70.0 cm for kuttum, golden grey mullet and common carp, respectively. The instantaneous coefficient natural mortality were estimated as 0.386 and 0.35 year-1 for kutum and golden grey mullet, respectively. During three periods, the exploitation rates were 0.789, 0.584 and 0.614 for kutum and 0.71, 0.75 and 0.61 for golden grey mullet, respectively. In the years 2007-2007, 2008-2009 and 2009-2010, the total biomass, from the biomass-based cohort analysis were 56600, 62090 and 61590 tonnes for kutum and and MSY estimated about 24733.7 and 8550.4 tones for kuttum and 11040, 11900 and 14460 tonnes for golden grey mullet, respectively. The ABC (acceptable biological catch) were estimated as 8000 and 2200 tonnes.