Population dynamic of bony fishes in Iranian waters of the Caspian Sea

This study was conducted to determine growth parameters, catch and fishing effort trends, stock assessment and Acceptable Biological Catch (ABC) of bony fishes in the Iranian coastal waters of Caspian Sea in the years 2013-2014 and 2014-2015. According to the result, the numbers of beach seines were 124 and 120 and their fishing efforts were observed 44688 and 46299 beach seining, respectively. The total catches (including illegal fishing) were also obtained 17144.3 mt and 16733.2 mt during 2013-2014 and 2014-2015, respectively. The highest proportion of catch was belonged to kutum and golden grey mullet (94.4% and 89.5%, respectively) in two fishing seasons mentioned above. Growth parameters of kutum were estimated as K=0.19/yr, L_∞ =61.3 cm, t0=-0.99/yr. The Growth parameters were K=0.18/yr, L_∞= 61.1 cm, t0= -0.14/yr for golden gray mullet and were K=0.14/yr, L_∞= 70.8 cm, t0= 0/yr for common carp. Based on catch-at-age data, in the years 2013-2014 and 2014-2015, the total biomass, from the biomass-based cohort analysis were estimated 46900 mt and 41000 mt for kutum and 11550 mt and 12670 mt for golden grey mullet, respectively. The reference points of F0.1 and F35% were 0.41/yr and 0.34/yr for kutum and 0.36/yr and 0.33/yr for golden grey mullet, respectively. According to catch of species/groups, three main groups can be divided easily. The one–way ANOSIM catch similarity test indicated that coverage rates of different years were homologous and similar, but the coverage rates of different months, regions and periods were not similar. Also, there were significant differences in community composition of fishes in catch of beach seines among three times; three durations; three regions and seasons (in all cases MRPP, p<0.001). During 1996-2000 species Rutilus rutilus, Vimba vimba, Chalcalburnus chalcoides, Aspius aspius, Barbus sp, Salmo trutta caspius and Silurus glani in the years 2000-2005 species/groups shads, Abramis brama and Esox lucius and in the years 2005-2012 species Cyprinus carpio and Stizostedion lucioperca were indicator species. Also, in the west region of the Caspian Sea species/groups Vimba vimba, Chalcalburnu schalcoides, Aspius aspius, Barbus sp, Abramis brama, Stizostedion lucioperca, Esox lucius and Silurus glani; in middle Rutilus frisii kutum, shads and Salmo trutta caspius and in east species/groups mullets, Rutilus rutilus and Cyprinus carpio were identified as indicator species. Based on available models, the ABCs were estimated as 8250-9750 mt for kutum and 1650-1950 mt for golden grey mullet (with precautionary approach 8250 mt and 1650 mt for kutum and mullet, respectively). For two species, the ABC with a lower and more accurate value based on more information, should be selected for the implementation of a precautionary management approach

The study of some limnological study of the Kan river in the catchment area of the Persian Gulf Martyrs Lake (Chitgar), Tehran trophic index in Anzali lagoon

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

The feasibility of Gamasiab river area fish farming of rainbow trout (Oncorhynchus mykiss)

This study was carried out about 15 months to determine suitable locations for the development of aquaculture across the Gamasiab river of Hamedan province in 2007 - 2008. Physicochemical parameters and macro benthic invertebrates fauna 15 and 13 stations respectively every 45 days and seasonally fish identify in 8 stations were performed according standard methods. The average water temperature was 12.8±3.7 oC, minimum and maximum dissoled oxygen were 2.6 and 12.5 mg/lit respectively during the study. The pH range was between 7.5-8.8 , the minimum and maximum Ec was 250 and 750 µmos/cm in Mehr and Tir. The transparency range was recorded about 1-103 F.T.U. The uder factors such as amount of suspended materials: 0.01-0.1 mg/l, amount of BOD5: 0.05-6.2 mg/l and COD: 30 (minimum) and 70.57 (maximum) were recorded. The total solids material (T.S.S) were less than 1 mg/lit. Totally 37 groups of bentic organisms were identified which 11 groups of them were appertained to pollution sensitive orders containing Ephemeroptera, Trichoptera and Plecoptera. During fish population studied 21 species belonging 5 family were identified. Based on obtained results of biological, ecological, economic and social parameters, 10 sites in 7 areas were suitable identified for fish rearing and 12 aquaculture programs (10 plan for fish rearing and 2 plan for increasing fish production of (Oncorhynchus mykiss). The minimum and maximum production capacity in mentioned places was estimated about 1675 and 3850 tons respectively

Caspian brown trout (Salmo trutta caspius) broodstock supply in south western of the Caspian Sea (Guilan province)

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