Monitoring and surveying fingerlings releasing (Kutum bream and pike perch) in quality and quantity point of view

Due to having so many commercial fish species, the Caspian Sea has special importance. In order to enhancement and restocking of some fish species such as kutum, bream, pike perch and common carp that their stocks were under damage, shilat company annually released fingerlings of these species into the river of Iranian part of the Caspian sea specially for kutum, bream and pike perch in Guilan province. Monitoring and surveying of fingerlings releasing in quality and quantity point of view, from loading to offloading place was done by fisheries research center of Guilan province. The mean number of fingerlings per loading in 2000 was about 11808 with minimum and maximum of 30000 and 616000 fingerlings Respectively, The caring time from culturing pond to the western river of Guilan was more than the same for eastern rivers; but the number of fingerlings per loading for western rivers were much more with. Comparison to eastern one and it is recommended .that the, fingerlings density per, loading should be adjusted by, distance that is better to be much' more for near distance. The weight range of fingerlings was recorded as 0.55 to 1.6 gr with an average of 1.02 gr. The fingerlings: release of kutum to the rivers such as Chalvand, Lemir, Kargan roud, Navroud, Khalehsara, Anzali lagoon, Sefid roud, Chamkhaleh and Khoshk roud were 1.01,6.4 milions respectively. Totally, 79087605 •fingerlings of kutum released to the Guilan province rivers. The most kutum fingerling released, had a weight range of 0.6 to 1 gr (56.6 milions fingerlings). Also the peak of releasing was in August (31.7 milions fingerlings). Surviving rate of kutum in 1991 was estimated 8.4% e That showed 16% decrease-with„comparison-to-1996-and-1-99-7.In study of parasitic diseases in fingerlings Diplostomum (digen), Tricodina, giroductylus (monogen) were recognized, among these, Diplostomum was more important for pathogenesis. The percent of contamination by diseases in 2000, highly decreased in comparison to 1995. The rate of pike perch fingerlings release from 1990 to 2000 had an increasing trend and from 16000 fingerlings in 1990 reached 3.8 million fingerlings if 2000.¯Nümber Si li on s-respectively-he-mean number fingerlings per loading for the above mentioned rivers were 103467, 76227, and 89300 fingerlings respectively. Pike perch fingerlings released in May (2.5 million fingerlings) and gune (0195 million fingerlings). Released number of Pich perch fingerlings peaked in weighting range of 0.5-1 gr and average weight of fingerlings was 0.9 in 2000. Although some fingerlings were released below 0.5 gr. During 10 years ago the catch of bream is to be grow up gradually and had some fluctuations. Totally, 14.5 milions of bream fingerlings were released in to the Anzali lagoon, the number of fingerlings per loading was 75057 with minimum and maximum of 11200' to 140000 fingerlings respectively. Mean weight of bream fingerlings in 2000 was better than previous years and reached 1.15 gr. releasing of bream fingerlings was in July (7948250 fingerlings) with average weight of 1.4 gr, but in August this figure decreased to 0.75 gr. The weight range of released bream fingerlings was 0.5-2.2 gr and maximum number of released fingerlings had a weight range of 0.6-1 gr. return coefficient of bream in 1993 was 1% which showed decrease in comparison to 1991.

Iranian Fisheries Science Research Institute

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