The scientists from the Laboratory in Honolulu who made 

 the dives aboard the Afiherah write of their observations 

 with a cool dispassion ; they speak of them with excitement, 

 for what they saw has been seen by very, very few men. 

 They found the sloping .sandy plain featureless and almost 

 barren of life, except where it was dotted by coral growth 

 or rocky rubble: There hosts of creatures congregated. The 

 rocky ledges 10 to 60 feet high that interrupted the plain 

 were surrounded by clouds of colorful fishes. Above these 

 bottom-dwelling species swam schools of fishes of the mid- 

 depths. 



Wherever the steep face of the limestone underwater cliff 

 afforded a foothold, things were growing, and small feeding 

 fishes were swarming around them like bees about a blossom- 

 ing tree. It was at this considerable depth, about 500 feet, 

 that a scientist aboard the Affhrnih made what was perhaps 

 the single most important observation of the dives. There 



he saw skipjack tuna feeding on fishes an inch or so long. 

 The depth to which the .skipjack tuna traveled had never 

 been known before. The fish are known almost entirely from 

 their brief visits to the surface in pursuit of prey. It was at 

 a depth of more than 500 feet, also, that the precious red 

 coral was seen. In crevices and ledges along the cliff face 

 were seen spiny lobsters of a size rarely caught in Hawaii. 

 Like the skipjack tuna, other fishes such as snapper, amber- 

 jack, and wahoo patrolled the cliff. In all, more than 100 

 species of fish were seen on the Ashemh dives. There were 

 literally millions of the small forage fish upon which the 

 larger, commercially important species feed (figs. 22 and 

 23). 



These fishes were observed near the shores of Oahu. 

 Whether the same conditions obtain in the open sea is not 

 known ; hence the interest in the use of larger submersibles 

 and a sensitive sonar in fishery studies. 



FISHES AND GEAR 



Once the subsurface stocks of skipjack tuna are located 

 the next step will be to harvest them. The only subsurface 

 tuna stocks yet taken are those which the Japanese and the 

 Hawaiians catch on their longlines. Under the direction of 

 John J. Magnuson, a group of scientists at the Laboratory in 

 Honolulu has spent several years studying facets of the 

 behavior of tunas (fig. 24). From these studies may come 

 the clues nece.ssary to the construction of new types of 

 fishing gear, and shifts to new methods. 



Fishes of the open sea have been most successfully caught 

 by the longline, an item of gear which does not actively 

 seek the fish, but which the fish themselves find. According 

 to Magnuson, it is po-ssible that the best future gear for the 

 subsurface tunas will be designed on this principle. The gear 

 could be an adaptation of the longline, or it could be a drift- 

 ing net or trap. Along the coast of Europe, long nets are used 



to intercept the regular migrations of the bluefin tuna. If 

 the routes used by the Pacific tunas could be determined, 

 gear might be devised to catch these fish during their 

 migrations. Information on how well tunas see, hear, smell, 

 may afford new insights as to new types of gear and methods. 

 The Governor's Conference pointed to the existence in the 

 central Pacific of a tremendously large stock of tunas and 

 examined the problems of locating and catching them. The 

 solution of these problems is a long-term project. The con- 

 ference also had more immediate results. It suggested 

 several ways in which the catches of the present Hawaiian 

 fisheries could be improved — by easing the bait problem and 

 thus allowing the fishermen to spend more time fishing for 

 tunas; by encouraging offshore fishing; by testing methods 

 successful elsewhere but untried in Hawaii, notably the use 

 of a light-weight synthetic purse seine developed by the 



35 



