PRELIMINARY REPORT ON RESFFISH STUDIES ON BIKINI ATOLL 
4 
V* 
March- April 1946 
The original plan was to occupy several rotenone poisoning 
stations on Bikini Atoll reefs for the purpose of getting a relative 
index of abundance of fish life. In the use of the rotenone it was 
not intended to do so much poisoning that measurable damage would 
result to the fish fauna and might be detectable after the bomb 
blast. Poisoning stations were thus well separated but their 
location depended largely on accessability of the reef and suitable 
habitats for working. This made it necessary to locate the stations 
close to the islands on which landing was feasable at high tide. 
The broad flat expanses of the reefs, where the water flows over in 
V * 
large quantities at high tide has little or no cover for fishes 
and is unsuitable for measuring fish abundance by the poisoning 
method. The stations selected represent the best habitats that 
were available in the area visited and were selected after careful 
reconnaissance. 
These habitats may be classified as follows: (1). Outer edge of 
ocean reef in surf among corals, channels, and algae. This zone 
is about 50 to 75 feet wide in most localities. (2). Ocean reef with 
corals 1 to 4 feet high, some algae, with narrow to wide channels 
between, or scattered coral heads, srnd with the water 2 to 5 feet 
deep at low tide. Bottom usually sandy. (3). Lagoon reef with 
corals, 1 to 4 feet high, smme algae, narrow channels or crevices 
with water up to 6 feet deep, occasionally deeper. (4). Shallow 
tidal pools, high up on reef, usually not over 1 1/2 feet deep, 
isolated at low tide, with scanty growth of corals or none. (5). 
Pond-like tidal nool connected with lagoon at high tide. 
