Occurrence of ectoparasitic isopod Norileca indica (H. Milne Edwards, 1840) on bigeye scad Selar crumenophthalmus (Bloch, 1793) from Great Nicobar Island, India.

Present study records the occurrence and range extension of an ectoparasitic isopod, Norileca indica (H. Milne Edwards, 1840) from the branchial cavity of bigeye scad Selar crumenophthalmus (Bloch, 1793) collected from Pilobah, Great Nicobar Islands. Detailed morphological characteristic of the parasite were presented along with prevalence, mean intensity and abundance. Out of the 130 specimens of S. crumenophthalmus examined, 32 were found to be infested with N. indica. The sizes of the female specimens were in the ranges 14.0 to 20.1 mm and the male specimens were 13-14 mm.