Observations on the food and feeding habits and recovery of a new nematode species Dujardinascaris mujibi (Heterocheilidae) from a marine edible fish of Karachi coast, Pakistan

Abstract

Food is an important factor in the fish biology, to the extent of governing their growth, maturity and migratory movements. Therefore, this research was aimed to investigate the feeding habits of marine edible fish Sphyraena forsteri (Cuvier, 1829) collected during February 2006 to July 2007 from fresh landing at fish harbor, Karachi coast, Pakistan. The gut analysis of 120 fish specimens were analyzed by using occurrence method and frequency of occurrence. The food items were grouped into 7 categories. Crustaceans and miscellaneous were the dominating categories followed by teleosts and molluscs. No significant seasonal variations in food contents were observed. Different parasitic species were found along with food content of some fishes studied. The most dominant parasites were Nematodes that might be the best indicator for food analysis. These parasites were not the part of the food content and may be swallowed with some food items, as the fish is an intermediate host for nematode parasites. Identification of nematodes was made through Scanning Electron Microscopy and compared with literature, which revealed the recovered nematode as new species, Dujardinascaris mujibi n.sp., along with some already known reported nematodes whereas infestation were detected in intestine of 10 fish specimens.