Jackson Estuarine Laboratory

Abstract

Bacteria belonging to the genus Vibn'o were demonstrated as etiologic agents of disease in captive sharks, following their isolation from a dead sandbar shark, Carcharhinus plumbeus, and from experimentally infected lemon sharks, Negaprion brevirostris. Studies were expanded to healthy, freeranging sharks captured and sampled for bacteria at Bimini, Bahamas. The bacterial flora of 28 neritic sharks, comprising five species, were examined. All 28 sharks were colonized with bacteria, primarily the genus Vibrio. All tissues and organs sampled contained Vibrio spp.• including liver, spleen, kidney, eye, mouth, skin, pancreas, intestine, stomach, gall bladder, gill slits, and fetuses (from a pregnant sharpnose). The conclusion, based on over 300 bacterial isolates from over 50 healthy sharks, is that sharks contain an autochthonous flora in most tissues and organs. The bacteria typically number between 102 and 105 bacteria per gram of tissue except blood, which is free from both aerobic and anaerobic bacteria. Human pathogens among the isolates included V. alginolyticus, V. parahaemolyticus, Listonella damsela, and Clostridium spp. While their ecological niche remains an enigma, it is clear that bacteria in healthy sharks can derive nutrients from elasmobranchs and, under conditions of stress to the host, cause death. Equally clear is the fact that when used as food, shark meat must be thoroughly cooked to destroy potential pathogens. If not properly cooked, pathogens such as V. parahaemolyticus could initiate gastroenteritis.

Publication Date

8-1-1990

Journal Title

Elasmobranchs as living resources: Advances in the biology, ecology, systematics, and the status of the fisheries

Publisher

NOAA, National Marine Fisheries Service

Document Type

Article

Comments

This is an article published by NOAA in Elasmobranchs as living resources: Advances in the biology, ecology, systematics, and the status of the fisheries, in 1990.

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