چكيده انگليسي :
Anzali wetland is the most important wetlands of Iranian and the most valuable wetland in Iranian Caspian Sea basin. This lagoon has commercial, sporting, recreational, engagement and genetic diversity, and it has special freshwater fish species, and it is impotant for migratory and spawning of migratory fishes, too. Anzali lagoon is an important aquatic ecosystem in releasing of fish fingerlings produced by Iranian fisheries organization. This study has been done in 4 basins of the wetland, east, west, center and south area, and north (and estuary), and in 11 important rivers to Anzali lagoon, consist of Chafrud, Bahambar, Morghak, Khalkaee, Palangvar, Masulrukhan, siadarvishan, Pasikhan, Pirbazar, Tashrud and Sheijanrud, from April 2016 until September 2017 and the main porposes were identification, distribution and abundance of native and alien fishes from resident or migrant forms and determination of length, weigth, age and sex ratio. There was used eclectric gear for fishing inside lagoon and its rivers, too and they have been selected 3 to 5 stations in lagoon and its rivers. The result on about 20,000 fish individual in all studied area showed 57 species belong to 15 fish families exist in Anzali wetland basin and Cyprinidae, Gobiidae, Clupeidae and Percidae with 26, 9, 4 and 3 species, respectively, had the most diversity. They were identified 43 and 27 fish species inside wetland and its estuary and totally 52 species, and in rivers entering wetland with 38 fish species, which of them, Siahdarvishan river with 34 species had the most diversity and Morghak river with 11 species had the least diversity, respectively. 31 fish species belong to fresh water resident, 9 species belong to migratory fishes, 12 species belong to estuary and some species had 2 or 3 habitat, too. Exotic and native or endemic fish had 13 and 44 species, respectively. Alburnus chalcoides and Carassius gibelio observed in all stations in lagoon and its rivers. Gambusia holbrooki with 22.8%, Carassius gibelio with 19.7%, Hemiculter leucisculus with 12.1%, and Blicca bjoerkna with 10.1% were abundant inside Anazli Lagoon. Alburnoides samiii, Capoeta gracilis and Ponticola iranicus with 24.8%, 17.1% and 16.6 were abundant among 38 identified fish species in all rivers, too. In a conclusion, it can be told Blicca bjoerkna and Cyprinus carpi have not problem, now, Abramis brama, Scardinius erythrophthalmus and Esox Lucius are vulnerable, but the position of 7 economical species of Anzali Wetland consist of Leuciscus aspius, Luciobarbus capito, Rutilus lacustris, Tinca tinca, Silurus glanis, Perca fluviatilis and Sander lucioperca is very bad and need severe notice of related organizations and the real lovers of environment, too.
The study of reproductive characteristics of important commercial fishes of Anzali wetland, consist of Esox Lucius, Blicca bjoerkna, Carassius gibelio, Cyprinus carpio, Hemiculter leucisculus, Perca fluviatilis, Scardinius erythrophthalmus and Tinca tinca has been done in this project, too.Total length and body weight of females were more than males in all studied fish species. Dominant age composition in adults was 2-5 in males and 2-7 in females, too. The ratio of males was more than females in E. Lucius, H. leucisculus and P. fluviatilis and it was less than females in the other fish species with significan difference. Maturity took place at 1 year old in C. gibelio, H. leucisculus and P. fluviatilis, 2 years old in E. Lucius and B. bjoerkna and 3-years old in C. carpio. Spawning season was January to February for E. Lucius, winter for P. fluviatilis and spring and summer for other fish species (Cyprinidae), too, on basis of gonado-somatic index and composition of gonad maturity stages of adult females. Absolute fecundity was assessed the most for common carp (238014 eggs) and the least for white bream (6898 eggs), too. The averages of egg diameter was determind from 0.62 mm in H. leucisculus to 1.89 mm in E. Lucius, too.
Feeding indices of 8 commercial fish (Hypophthalmichthys molitrix, Hemiculter leucisculus, Ctenopharyngodon idella, Scardinius erythrophthalmus, Cyprinus carpio, Carassius gibelio, Esox Lucius and Perca fluviatilis were determined in this project, too. Results showed that intensity of feeding was higher than 400 in 2 species, 200-400 in 3 species and lower than 110 in another species and there was seasonal changes, so that the minimum amounts of the index was observed in winter but maximum values related to another seasons in relation to fish species. There was at least one food items in the alimentary tract of 92% of H. molitrix, 94% of H. leucisculus, 84% of C. idella, 86% of S. erythrophthalmus, 75% of C. carpio, 98% of C. gibelio, 81% of E. Lucius and 62% of P. fluviatilis specimens and indicated high feeding in 6 fish species and relatively high feeding in c. carpio and P. fluviatilis, too. There were 39 genera from phytoplankton and 2 genera from zooplankton in the gut of H. molitrix, 7 genera from high plants, 7 taxa from benthic animals, 8 groups from nektonic invertebrates and 5 fish species and also 22 genera from phytoplankton and 4 genera from zooplankton in the gut of H. leucisculus, 5 genera from high plants in the gut of C. idella, 6 genera from high plants, 13 taxa from benthic animals, 3 groups from nektonic invertebrates and 2 fish species in the gut of S. erythrophthalmus, detritus and addition to particles of high plants, filamentous algae, 12 taxa from invertebrates belong to vorms, mussels, crustaceans, insects and 3 fish species and in the gut of C. carpio, and detritus analysis in some individuals showed 21 genera from phytoplankton and 3 genera from zooplanktons, too. There was 45 genera from phytoplankton and 16 genera from zooplankton, 4 taxa from benthos and one fish species in the gut of C. gibelio, 2 genera from zooplankton, 9 taxa of invertebrates and 28 fish species in the gut of E. Lucius and finally 5 taxa from insects, 2 groups of crustaceans and 6 fish species in the gut of P. fluviatilis. In general, it can be told E. Lucius, H. leucisculus and C. carpio have had the most diversity of preys among studied fish species in Anzali lagoon.
