BIOLOGY OF BIKINI ATOLL — SCHULTZ 303 



drilled by the G. E. Failing Supply Co., under the direction of the 

 geologists. 



The study of the effect of radiation on marine animals, especially 

 fishes, was made during 1946 and 1947 by the University of Washington 

 group under the direction of Drs. Lauren K. Donaldson and Arthur J. 

 Welander, School of Fisheries, Seattle. 



Since fishes represented the group of animals of greatest economic 

 importance in and around the atoll, emphasis was placed on them. 

 Statistical studies were attempted in 1946 and 1947 with the view 

 of measuring the relative abundance of fishes, those caught by trolling, 

 and on the reef by other means. The pelagic kinds — tuna and their 

 relatives — were caught by commercial fishermen^ using trolling meth- 

 ods. This work was under the immediate supervision of John C. 

 Marr and Osgood R. Smith, United States Fish and Wildlife Service. 

 Similar population studies were made of the lagoon and reef fishes 

 by Vernon E. Brock, director, Division of Fish and Game, Territory 

 of Hawaii, Dr. Earl S. Herald, United States Fish and Wildlife Serv- 

 ice, and Dr. Leonard P. Schultz, curator of fishes in the United States 

 National Museum, Smithsonian Institution. The latter and Loren 

 P. Woods, curator of fishes, Chicago Natural History Museum, are 

 preparing a descriptive catalog of the fishes of the northern Marshall 

 Islands. 



BIKINI ATOLL AS A FISH HABITAT 



Bikini Atoll in shape resembles a bathtub, except that its sides are 

 cut through by several deep channels. It is about 22 miles long by 13 

 miles wide, inclosing a lagoon whose depth is mostly 180 feet with 

 a few areas down to 200 feet. Rising from the lagoon floor are large 

 coral heads, a few of which come near the surface, whereas around 

 the margins of the atoll reef are more coral heads that reach the sur- 

 face. The lagoon floor slopes gradually upward from its deeper parts 

 to those areas exposed during the low tides. The bottom is composed 

 of loose sand, fragments of calcareous algae, and coral remains, on 

 which are growing a great variety of sessile invertebrates, aquatic 

 algae, and into the rocky fragments worms burrow. In otherwise un- 

 used crevices, fishes hide. 



SANDY AREAS 



Considerable areas adjoining the rim of the atoll in the shallower 

 parts of the lagoon are composed of loose sand. In places where this 

 sand is continually shifting, no corals occur, but where it remains 

 stable small isolated ones from a few inches to 2 or 3 feet high occur. 

 These areas are somewhat barren of fish life. 



Usually around coral clusters are a few kinds of damsel fishes, one 

 or two species of wrasse, scorpion fish, often gobies and blennies. 



