Host-specificity of metazoan parasites infecting mullets of Kerala, India.

Eight species of mullets occurring in the estuarine habitats of Kerala, India, were examined for the presence of metazoan parasites. Of the 50 species of metazoan parasites encountered, 18 (36%) were oioxenic and 6 (12%) euryxenic; 48% of the parasites infected two to four host species and 4%, more than four host species. Among monogeneans, one species (16.7%) was restricted to a single host species and one species was seen to infect all the eight host species. Of the 12 digeneans, 3 (25%) infected a single host species and two (16.7%) were found on all the eight species of hosts. Among the 25 species of copepods, 12 (48%) were restricted to one host species and two (8%) infected all the host species. The overall picture forthcoming from the study is that the metazoan parasites of the mullets of Kerala waters showed varied levels of specificity with respect to their hosts; about 1/3 of them are highly host-specific, whereas, only 1/8 of them is distributed in all the host species.