Abstract

Farmed rainbow trout (Oncorhynchus mykiss) were examined for anisakid nematodes at fish farms in Elazıg city, Turkey. A total of 439 fish (246 from fish farm ponds and 193 from net-cages) were monthly investigated in the period from February 2000 to May 2003. Only the endoparasite, hysterothylacium aduncum (Nematoda: Anisakidae) was recorded in the digestive tract of the 91 cultured rainbow trout, O. mykiss fed with minced marine fish. Prevalence, mean intensity, and the abundance of H. aduncum on fish obtained from fish farm ponds were 36.99%, 16.00 ± 1.15, and 5.92 ± 0.15, respectively. However, this values in fish fed with freshly minced marine fish were 100%, 16.00 ± 1.15 and 16.00 ± 1.15, respectively. H. aduncum was found in the oesophagus, stomach, intestine, and pyloric caeca of fish. All H. aduncum were adult and was not found on fish fed with commercial pellets.

Key words: Hysterothylacium aduncum, rainbow trout, nematoda, anisakidae.