ASFB Home > 2003 > Biological Invasions: Consequences for Parasites, Pathogens, Emerging Diseases, and Fisheries in the Marine Environment.

Impact of the invasive ctenophore Mnemiopsis leidyi on the Kilka fisheries Clupeonella engrauliformis in the Southern Caspian Sea

Hassan Ghadirneja

Iranian Fisheries Research Organization (IFRO); P.O. Box 14155-6116, Tehran, Iran.
Email: Ghadirnejad@yahoo.com

The present paper evaluates the impact of mass occurrence of M. leidyi in the Southern part of the Caspian Sea on the Kilka fisheries (clupeidae family; C. grimmi, C. engrauliformis, C. cultriventris). A background of fisheries in the Southern part of the Caspian Sea including Kilka fisheries and catch trend in the last decade is given.

Southwest part of the Caspian Sea has the highest density of M. leidyi with values of up to 2285 individuals per cubic meter. The impact of such high densities of M. leidyi is significant especially for the pelagic ecosystem including Kilka (C. engrauliformis) stocks. Evidence of relationship between mass occurrence of M. leidyi and sharp decreases of Kilka (C. engrauliformis) stocks is discussed.

Anchovy kilka (C. engrauliformis) is living in the same range of depth (10-25m) as invasive ctenophore is present massively which highlights the impact on the biomass of anchovy kilka species by sharp decrease in the catch trend. The catch composition has changed. Anchovy Kilka was dominant with 85 to 90% in the catch at the early stage of Kilka fisheries and nowadays has dropped to only 55%. Common Kilka is dominant in the catch composition these days.

Finally, some suggestions are given to reduce the impact of this invasive ctenophore on the Kilka fisheries.

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