Studies on endoparasitic copepods: Sarcotaces arcticus (Copepoda: Phylichthyid) infested dotted grouper (Epinephelus epilistictus) from the Arabian Gulf water, Saudi Arabia

Abstract

This study aimed to investigate the presence of Sarcotaces sp. in Epinephelus epilistictus (the dotted grouper) in Saudi Arabia. So, during our routine clinical examination of fish health conditions at Jubail province in the eastern region of Saudi Arabia (Arabian Gulf), nine grouper fish species were examined for Sarcotaces sp. (Copepoda: Phylichthyidae). Only the dotted grouper (Epinephelus epilistictus) harbored parasitic Sarcotaces spp. with an incidence of 9.06% of 1600 clinically examined fish samples. The collected Sarcotaces sp. was Sarcotaces arcticus (S. arcticus). The copepods were completely encapsulated cysts with a pyriform or pear-like shape, small to large, white-grayish, fluid-filled with thick black ink beneath the skin, or fully embedded in the muscular layer. The cysts present in the lateral aspect of trunk muscles, flank, caudal peduncle, near the anal opening, or pelvic and pectoral fin with an infestation rate (1–6 cysts) per fish. The cyst histopathology reveals the capsular layer of the cyst consisting of fibrous connective with pressure atrophy of the adjacent muscles associated with dilated blood vessels. The absence of infestation in other kinds of grouper fish species from the water of the Arabian Gulf in Jubail province may indicate parasitic host specificity and geographic locality distribution.