152 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 9 



USE OF ROTENONE FISH POISONS 



In our paper on Atherinids (Allan Hancock Pacific Expeditions, vol. 

 9, no. 5) we have given notes on one effective method of marine ichtyo- 

 logical collecting, the use of the electric light in night collecting from the 

 ship. We now present an even more useful method. 



Some of the fishes described below were obtained by the use of 

 vegetable "fish" poisons, which are perhaps the most useful of all tools to 

 the ichthyological collector. Although the aborigines of most parts of the 

 world use plant juices of many kinds to stupefy and kill fish to eat, the 

 general use of fish poisons by the scientific fish collector is a relatively 

 recent development. Probably the first ichthyologist to use fish poisons 

 regularly was the late David Starr Jordan, and it is largely to this method 

 that we may attribute the hitherto almost unheard of variety of small 

 fishes he and his students obtained in Japan, Samoa, and other Pacific 

 localities. Jordan usually used chloride of lime, and the method is 

 mentioned in his Guide to the Study of Fishes (1905). The late Dr. 

 Carl H. Eigenmann was apparently the first ichthyologist who made 

 regular use of native vegetable fish poisons, and his classical account of 

 his first results, in the introduction to his Freshwater Fishes of British 

 Guiana (1912), should be read by every ichthyological collector. As a 

 matter of fact, it was Eigenmann, and his student, Dr. William Ray 

 Allen, who first suggested the importation of the dried roots of fish 

 poison plants into the United States as an insecticide, the story having 

 recently been published in their Fishes of Western South America 

 (1942). The subsequent immense growth of the commerce in the roots 

 both of the Asiatic Derris elliptica and of various tropical American fish 

 poison plants (called timbo in Brazil, barbasco or cube in Peru), for use 

 in insecticides, provides the scientific fish collector with a ready means of 

 supply. The first use of the commercial product was made by Dr. Carl 

 L. Hubbs. The literature of economic entomology now abounds with 

 papers on the various rotenone poisons. In addition to those given by 

 Eigenmann and Allen (1942), we give only one (Holman, 1940) which, 

 incidentally, mentions Allen's work in Peru. 



The active principle in these roots is said to be rotenone, but Dr. A. W. 

 Herre tells the senior author that one of the chemists of the Bureau of 

 Science in Manila found other and even more potent piscicidal elements in 

 derris root. In any event, the action on the fish is one of suffocation, a 

 prevention of exchange of oxygen in the gills, and the gill filaments in 

 derris-killed fish are of a peculiar bright red color. The "poison" does 



