POISONOUS FISHES 325 



puller, moray eel and red snapper are believed to become poisonous 

 because of their eating habits. 



The acquisition of poisonous properties by a fish is thought to be 

 derived as a result of herbivorous fishes feeding on poisonous marine 

 algae. Carnivorous fishes would become poisonous by feeding on poi- 

 sonous herbivores. Controlled laboratory feeding studies have demon- 

 strated that at least one species, Leptocottus armatus Girard, the Cal- 

 ifornia staghorn sculpin, has the ability to feed on poisonous fish flesh 

 and harbor the poison in various tissues of its body with no apparent 

 alteration in its behavior. Studies are now in progress on this particular 

 phase of the program and will be reported at a later date. This food 

 chain theory has been presented in greater detail in our "Survey of the 

 poisonous fishes of the Phoenix Islands." ^ 



Ichthyosarcotoxism in man is frequently confused with various 

 types of bacterial food intoxications. True fish poisoning is in no way 

 related to putrefactive processes, hence the state of freshness of the fish 

 has no bearing on the production nor the potency of the poison.* The 

 chemical nature of these poisons, exclusive of puffer poison, are un- 

 known. Some fish poisons appear to- exert a variety of physiological 

 effects which represent the combined action of the different compo- 

 nents. Many of the symptoms resemble those produced by such com- 

 pounds as aconitine, muscarine and curare. Many of the scombroid 

 (tuna-like) fishes produce rather violent histamine-like reactions, which 

 appear to be dependent on the freshness of the fish. On the other hand 

 some of the skipjacks contain neurotoxins which are frequently present 

 in freshly caught specimens. 



Japanese scientists have studied tetraodon toxin or puffer toxin in 

 great detail. Tetraodon toxin has been assigned the provisional formula 

 of CisHgiNOig. It has been isolated as a white hygroscopic powder 

 soluble in water and insoluble in the ordinary organic solvents. It is 

 neither a protein, an alkaloid, nor a protamine. The exact chemical 

 nature and relationship of other ichthyosarcotoxins have not been stu- 

 died to date. All fish poisons, however, are water soluble and relatively 

 heat stable. Ordinary cooking procedures do not destroy or appreciably 

 alter the potency of the poison. 



Clinical Characteristics 

 Since the Pacific Science Congress is primarily concerned with 

 Pacific research, the discussion of the clinical aspects of ichthyosarco- 

 toxism is limited to the four clinical types of ichthyosarcotoxism com- 

 monly recorded for the Pacific area. 



• The only exception to this statement is in the case of scombroid poisoning which results 

 from eating- inadequately preserverl fishes. However, the symptoms are quite different from 

 ordinary, types of bacterial food poisoning. 



