Abstract
The present paper reports fundamental aspects of host-parasite interaction between a cymothoid isopod, Norileca indica (Milne Edwards, 1840), and the fish Indian Mackerel Rastrelliger kanagurta (Cuvier, 1816). N. indica is recovered from the branchial cavity of the host fish R. kanagurta. The appendages like pereopods and the mouth part of N. indica exhibit morphological adaptation for the parasitic mode of life. The parasitic mode of feeding in N. indica was confirmed by amplifying DNA from its gut contents, which matched the tissue of the host fish (R. kanangurta). The effect on the host fish includes a reduction in the length and weight of the host fish. The continuous lodging of the parasite inside the gill chamber causes the degeneration of the gill filaments of the host fish. Further, the mucus protease activity was higher in infected fish when compared to uninfected fish. Overall, this paper tries to address the effect of cymothoid parasitism on marine fishes.