• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.68-71
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• 1998

The egg structure and shape of the skin parasite, Entobdella hippoglossi from the Atlantic halibut, Hippoglossus hippoglossus was examined using scanning electronic microscope. The newly produced eggs of E. hippoglossi were yellowish in color and tetrahedral in shape. The eggs were entwined together in a complicated chain-like fashion by a long filament. The appendage showed the presence of buoy-like structures. The buoy-like structures on the appendage of the eggs of E. hippoglossi in the present study were totally different from other sticky droplets. It is suggested that these structures are not sticky droplets but buoys for floating eggs which have entwined together on the bottom of the sea. It seems that these buoy-like structures may be needed for preventing the eggs from being covered by mud or particles and thus maintaining the eggs in an oxygenated environment.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.63-67
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• 1998

The host finding behavior of Entobdella hippoglossi oncomiracidium, skin parasite of the Atlantic halibut was investigated. Almost of the parasite swam downward from the top to the bottom of the 150cm glass tube within 30 minutes. The average swimming speed of oncomiracidium was $0.32\pm0.10cm/second$ throughout the experiment. When the parasites arrived on the bottom of the glass tube, they moved upwards and downwards continuously within the 10cm of the bottom. This behavior would suggest that it may be one of the essential methods for host searching of the parasite. When the oncomiracidia was exposed different stimuli, they responded positively light and halibut mucus.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.433-433
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• 2000

The monogenean skin parasite, Entobdella hippoglossi has commonly be found broodstock of the Atantic halibut. Heavy infestation of the parasite appears to be serious problem to the halibut farming industry. However, because the behavior of host, research on this parasite is not yet be carried out. The present study, therefore, was investigated the oncomiracidium of Entobdella hippoglossi to the basic step for solving this problem. (omitted)

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.134-138
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• 1999

This study investigated the relationship between attachment site preference of the skin parasite, Entobdella hippoglossi and mucous cell density, moucus cell size and epidermis thickness on the surface of the Atlantic halibut Hippoglossus hippoglossus. Parasites occupying the ventral surface of their host were significantly longer and wider than those found on the other zones of the fish (P<0.05). The mean size of the mucous cells on the front region was significantly greater than the other regions on the dorsal and ventral surface (P<0.05). The average numbers of mucous cells and the epidermal thickness in the skin of the halibut were shown that the front region had significantly higher numbers of mucous cells and thicker layer than the rear region on the dorsal and ventral surface of the halibut, respectively (P<0.05).