Drifting Object and Pelagic Fish — Gooding and Magnuson 
487 
Fig. 1. The observation raft used in study. 
2 m at the Equator. Average wind speeds 
ranged from 10 to 15 knots. Cloud cover seldom 
exceeded 30%. 
The observation chamber beneath the raft 
(Fig. 3) accommodated a single observer, who 
could view the area beneath and around the 
raft. Two observers manned the drifting raft 
from dawn to dusk. Watch positions in the 
chamber were rotated each hour. Nights were 
spent on the ship, which remained 1-3 miles 
from the raft. A skiff provided transportation 
between ship and raft. 
The observers noted the number of each kind 
of fish at the raft, their position under or near 
the raft, and their reaction to the raft and to 
other fish or invertebrates. Night observations 
were made under bright moonlight, but a flash- 
light was used at intervals to determine more 
accurately the positions of the fish. The ac- 
cumulation was quantified by making population 
counts of the species present at intervals during 
the day. An estimate of population changes 
during the night was obtained by comparing the 
last count in the evening with the first count on 
the following morning. 
158° 157° 156° 155°W 
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155° 150° W 
Fig. 2. Areas in which drifts were made with 
the observation raft, off Hawaii ( upper panel) and 
near the Equator ( lower panel). 
Fig. 3. The observation chamber of the raft. 
Dark specks to right of chamber are small fish. The 
white object behind the chamber is the parachute 
drogue. 
