The present study analysed samples of Serra Spanish mackerel, Scomberomorus brasiliensis and largehead hairtail, Trichiurus lepturus captured from the coastal waters of Rio Grande do Norte, Brazil, with a view to verify the occurrence of metazoan parasites related to public health in these fish and determine the parasitic indices and sites of infection. In S. brasiliensis, 28 nematode specimens of Contracaecum fortalezae were encountered in the branchial chamber and gonads with 20% prevalence. Besides 24 trematode specimens of Didymocystys sp. were found in the tegument, muscles and branchial chamber with 40% prevalence. In T. lepturus, a nematode Hysterothylacium sp. was found in the intestine, with a prevalence of 33.33% and 641 digenetic specimens of Catarinatrema verrucosum were found in the tegument, branchial chamber and stomach, with a prevalence of 100%. The occurrence of the parasitic members of the family Anisakidae and the digenetic trematodes of the families Hemuridae and Didymozoidae have zoonotic potential and are related to public health since the fish hosts are of commercial importance.

This paper reports on parasitism in the marine fish Atlantic bumper Chloroscombrus chrysurus (Osteichthyes: Carangidae) by the cymothoid isopod Cymothoa spinipalpa as well as information pertaining to biological aspects. The fish samples were netted in the coastal waters of the Rio Grande do Norte, Brazil, and examined on a monthly basis from January to December 2006. A total of 30 adults of C. spinipalpa were found in 26 of the 204 Atlantic bumpers sampled. A prevalence of 12.8% and mean intensity of 1.15 parasites per fish were registered. The isopods were found in the branchial chamber and buccal cavity of the host. However, the parasitized and non-parasitized fish did not show any significant differences in their mean body mass, body length and condition factor. A positive correlation was found between the total length of female isopods and total body length of the hosts. The parasitic isopod females were larger than the males. Occurrence of males in the branchial chamber and the buccal cavity did not show any significant differences statistically, whereas the females showed a preference for the buccal cavity.