FIGURE 1. Living tuiiu> fur behaviurul experiments are 

 collect oil b> expert fishermen <>f the HCS Laboratorv'?. 

 \e»sei (harlen //. (filbert. At ih*' left, the struggling tuna 

 is ^Huiig over the shipV rail us technician Haits t<i guide it 

 to the hdlfliiig lank. In the other photograph, the fish is 

 gently hxwereH into the fiber glass lank, where it will Hwim 

 free. The men are standing on the lid of the lank. The 

 Laboratory in Honolulu is the oiil> one in the world where 

 living tunas are regularlv available fur behavioral studies. 



THE FISHES 



The World of fhe Tunas 



Fish and fish products, according to estimates of the Food 

 and Agriculture Organization of the United Nations (FAO), 

 provide man with 12 percent of the animal protein in his 

 diet. The percentage is small, but the surprising thing may 

 be not that men take so little of their food from the sea, 

 but that they are able to take so much, for the fish are 

 small and the ocean very large. Consider the catch of skip- 

 jack tuna, Katsuwoinoi pelamin (Linnaeus), in the Pacific 

 Ocean: About 100 million fish (550 million pounds) are 

 taken annually. These may represent one-tenth of the adult 

 population, which would then be 1 billion fish. These 1 

 billion skipjack are found in an oceanic area covering some 

 23-million square miles. If they were spread out evenly, like 

 checks in a plaid, then there would be one skipjack for each 

 0.023 square miles, or one for each 14.7 acres. To capture 

 3,000 of them, a relatively good catch, a boat would have 

 to collect every skipjack tuna in an area 10 miles wide and 

 69 miles long. 



But fishes are not distributed evenly. They seek out areas 

 favorable for feeding or spawning, they gather in schools, 

 they migrate from place to place with the seasons. Commer- 

 cial fishing is possible only because over the millennia keen- 

 eyed fishermen have noted and taken advantage of recurrent 



patterns in the behavior of fishes. Now these age-old obser- 

 vations are being extended and reinforced by the skills of 

 modern science. 



During the past few decades, scientists have learned a 

 great deal about the sensory capacities of fish and how the 

 animals behave. Much of that knowledge rests, however, 

 on experiments with species that have little or no commer- 

 cial value, with the notable exception of the salmon. 



Hindering efforts to conduct systematic experimental 

 studies of the food fishes of the open sea, such as the tunas, 

 has been the difficulty of maintaining the.se relatively large 

 and swift creatures in captivity. The Laboratory in Honolulu 

 has conquered this obstacle in a way that has made possible 

 several basic inquiries into the sen.sory capacities and be- 

 havior of tunas. 



Several times a year, the Charles H. Gilbert, the smaller 

 of the Laboratory's two research vessels, no.ses alongside 

 the dock in Honolulu carrying on her deck a cargo of what 

 look like oversized bathtubs with lids on them (fig. 1). A 

 complex of water hoses runs to and from the tanks. P^ach 

 container carries 5 to 10 live tunas caught only a few hours 

 previously by the Gilbert's crew of expert pole-and-line 

 fishermen. 



