Monitoring (biology and catch) of Kilka in commercial catch in 2000-2001

Abstract

Kilka fish has been catch in Iranian coastal waters in Mazandaran and Giulan provinces. During in 1999 to 2000 Kilka fishing ships discharged theirs catch in three pons, Babolsar, Amirabad (in Mazandaran) and Anzali (in Giulan). In this investigation which had been done in commercial catch regions, in addition of biological characteristics survey such as species composition, length, weight, age, sexual and stages of sexual maturity, catch amount and catch per unit effort also were analyzed. The results shown that catch. effort increased in 2000 (184 vessels) but catch amount and CUPE sharply decreased, as catch of kilka in Mazandaran and Gilan in 1999 decreased from 28 and 57 thousand tons to 19.6 and 42.6 thousand tons respectively. CPUE also decreased from 3900 kg in 1999 to 2500 kg in 2000. Between three species of kilka, anchovy dominated but the frequency of this fish decreased from 8590% to 76% and the frequency of common kilka sharply increased. Common kilka had been caught in spring and summer but in 2000 this fish caught all months. Anchovy spawn in spring and autumn but mass spawning anchovy occurred in autumn. Spawning of common kilka occurred in spring and early summer. The length frequency of anchovy is close and the bigger fish did not see in catch. The average length of anchovy decreased from 96.3 mm in 1997 to 87.3 mm in 2000. The age frequency had the same situation, as fish with 5+ and 6+ were not or had very low frequency. According to the reports mass group of Mnemiopsis leidyi saw in 2000 in south of the Caspian. The animal damaged the pelagic stocks in Black Sea. Probably Mnemiopsis caused this mentioned characteristics in the Caspian Sea.