Effect of invasion of comb jelly Mnemiopsis leidyi on Kilka fishery The Caspian Sea

سال انتشار: 1384
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 1,480

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تاریخ نمایه سازی: 18 دی 1384

چکیده مقاله:

Fishery of small pelagic clupeid was established in Iran in 1971. The peak of catch reported 95 thousands tons in 1999. Then, it was reduced sharply an showed 83% fall down between 1999 and 2003. Furthermore, catch per unit of effort (CPUE) was decreased during these years. CPUE of Kilka was 5.5 tons per night in 1991 but it dropped to 3.9 tons in 1999 and now it reached only about 1 tons. The sudden decrease in Kilka landings has also been seen in the fisheries of other Caspian coastal countries. For example, Kilka catches dropped for the Russia, Azerbaijan, Kazakhstan, and Turkmenistan from 2000. Dramatic reductions have been reported for Russia from 800 thousands tons in 1995 to 17 thousands tons in 2003. This reduction in Azerbaijan is about 41%. These are the sign of damaged Kilka stocks in the Caspian Sea. Appearance of Mnemipsis leidyi in the Caspian Sea caused species composition changes of Kilka. Anchovy Clupeonella engrauliformis was already dominant species in the commercial catch and also in research studies. Based on stock assessment investigation during 1996-97, stocks of Kilka was estimated 273.8 thousands tons. Anchovy comprised about 77%, Big eyed C.grimmi 141% and Common Kilka C.cultriventris 8.5%. These compositions were Anchovy 91.8%, Big eyed 6.8% and Common Kilka 1.4% in the landing. Nowadays, Anchovy and also Common Kilka comprise 50% of catch and Big eyed disappear in the commercial catch. In spite of catch reduction of small pelagic from 400 thousands tons to less than 50 thousands tons, in the Black Sea during 1984-88, but due to great sensitivity of the Caspian Sea as a closed basin, the impact of Mnemiopsis Caspian Sea could be very drastic.


Farokh Parafkandeh Haghighi

Iranian Fisheries Research Organization, P.O.Box: ۱۴۱۵۵-۶۱۱۶, Tehran, Iran