52. Are all fishes edible? 



Not all fishes are edible. Some have organs that are always poisonous 

 to man; others sometimes become toxic because of certain elements in 

 their diet. In Japan, a national dish called fugu is highly prized. It is pre- 

 pared from the puffer fish, and the gonads of the puffer are highly 

 poisonous. For this reason, fugu is only served in restaurants licensed 

 by the government. 



Consumption of sharks and rays has been known to cause illness or 

 death; this was probably because the victim ate a portion of the liver, 

 which contains a very high concentration of vitamin A that the human 

 body cannot tolerate. 



There are 300 tropical species of fishes that cause fish poisoning; one 

 type of poisoning is commonly known as ciguatera. A particular species 

 may cause ciguatera when caught on one side of an island, but not if 

 caught on the other side. These tropical fish are associated with reefs 

 and do not usually venture far from the home reef; for this reason, the 

 people living on one island may eat a certain species of fish, while those 

 on a nearby island would not. No one knows what causes the fish to be- 

 come poisonous, but most investigators agree that it is something in the 

 diet. There is no method to determine before a fish is consumed whether 

 or not it will cause ciguatera. Some common species of fish known to 

 cause ciguatera are: surgeon fish, jacks, porgies, snappers, goatfish, 

 moray eels, wrasses, and barracudas. 



Scombrid fish, commonly known as tuna or mackerel, have been 

 known to cause scombrid poisoning, usually because of inadequate 

 preservation. The flesh of scombrid fish contains bacteria which, if the 

 fish is not preserved soon after capture, begin to produce a histamine- 

 like compound. This compound, if ingested by humans, causes a severe 

 allergylike reaction and may even lead to death. 



Fish, C.J. and M. C. Cobb. 



Noxious Marine Animals of the Central and Western Pacific Ocean, 

 U. S. Dept. Interior, FWS, Res. Rept. 36, pp. 1-45. 



Norman, J. R. 



A History of Fisfies, Hill and Wang, 1963. 



Randall, John E. 



"A Review of Ciguatera, Tropical Fish Poisoning with a Tentative 

 Explanation of Its Cause," Bull. Mar. Sci. Gulf and Caribbean 8(3), 

 pp. 236-267. 



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