BIOLOGY OF BIKINI ATOLL — SCHULTZ 309 



use vegetable poisons, although aboriginal natives in nearly all parts 

 of the world have made use of them. Since that time most American 

 ichthyologists have used vegetable poisons to collect fishes for scientific 

 purposes. Drs. Eigenmami and W. R. Allen, University of Kentucky, 

 describe methods of collecting fresh-water fishes in their 1942 pub- 

 lication, "The Fishes of Western South America." 



From 1936 to 1938 the author experimented with the use of pow- 

 dered derris root in fresh-water streams, and during the second World 

 War, with the rotenone extract; the latter, however, did not appear 

 to be as effective as the powder. It was not until 1939 that an op- 

 portunity came to carry on extensive experiments. Upon arrival in 

 the Phoenix Islands, he found practically no enclosed tidal pools, 

 the type of habitat in which ichthyologists had previously used ro- 

 tenone fish poisons in small quantities. The reefs were flat, pavement- 

 like structures, with narrow to wide channels, connected with open 

 water, whereas the deepest isolated pools left at low tide were only 

 a few inches deep and often lacked fish. 



A large variety of fishes could be seen swimming in the chaimels, 

 in the open waters, and even in the ocean surf. These had to be 

 collected somehow. After carefully studying the currents and esti- 

 mating the depth of water, the author attempted the use of rotenone 

 in the open water among the corals and algae. At the end of July 

 1939, after 4 months' continuous work in various coral-reef habitats, 

 methods of using rotenone in open-water situations had been per- 

 fected and, as a result, over 14,000 excellent fish specimens were 

 recovered for the United States National Museum. 



When the author was asked late in 1945 about obtaining samples of 

 shallow-water reef fishes at Bikini, Operation Crossroads, for pur- 

 poses of determining the relative abundance of fishes before and after 

 the atomic explosions, he suggested the methods developed in 1939. A 

 few months later, during March to August 1946, and again in July 

 and August 1947, fishes were collected by the use of rotenone. Differ- 

 ent techniques were applied depending on the situation. As a result, 

 there were taken over 70,000 fish specimens on which systematic and 

 population studies could be based. Part of these were discarded after 

 data from them were recorded. 



Thirty-five minutes before the tide reached its lowest point, the dry 

 powdered root was placed in buckets or any suitable containers and 

 mixed with water to a thick chocolate malted milk consistency, allow- 

 ing about 20 minutes for one man to mix 25 pounds. By squeezing 

 and stirring with the hands as water was gradually added, the powder 

 soon formed a thick mud. Ten minutes before low water, the dis- 

 tribution of the mixture began. The stupefying of a great variety of 

 fishes with rotenone was most successful at the lowest stage of water. 



The success of this operation depended on determining the strength 



