Özet:

Abstract The parasite infection in cultured fish can be dangerous and cannot be treated immediately. Parasitic copepods are the most frequently encountered taxa parasitizing fish and cause significant economic loss in mariculture. The objective of this study were to determine the intensity and prevalence of copepodic parasite on cantang hybrid grouper (Ephinephelus sp.) and tiger grouper (Ephinephelus fuscoguttatus), and to determine the histological change caused by parasite infection. This study was conducted from five fish farmers at Batam waters, Riau Islands composed of seven cantang hybrid grouper populations, and two tiger grouper populations. For parasit observation, at least 36 fishes were randomly sampled from each grouper population. The fish showing symptoms of red nodules in the oral cavity was designed as positive infected fish. The counting number of  parasites was carried out by observation using a binocular microscope. The infected and uninfected tissues were preserved on neutral buffered formalin and processed for histology. The copepodic parasite was found both in cantang hybrid grouper (Ephinephelus sp.) and tiger grouper (E. fuscoguttatus). The parasite was found at high prevalence on cantang grouper with average prevalence of 62% with highest prevalence at 87%. The intensity copepodic parasite on cantang hybrid grouper were at low level with an average intensity of five parasites/fish. The infection on as tiger grouper with an average intensity of 4.5 and prevalence 40.25%. The prevalence and intensity of copepodic parasite on cantang grouper tends to increase with increasing fish size. Copepodic parasite infection in fish tissue caused congestion, polymorphonuclear, haemorrhage, hyperplasia and mucus proliferation.

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