the protein migrates toward the anode, the positive pole. 

 The different forms of esterase are characterized l)y their 

 relative mobility, the rate of migration. The samples are 

 strained with a dye so that they appear as brown bands 

 on the plate. Thus after the samples have been treated 

 for a period of a few hours, there will be bands on different 

 parts of the plates. 



What the possession of these subtly different types of 

 esterase may mean physiologically to the fish is uncertain, 

 except for the broad biochemical function noted above. The 

 thing that makes serum esterase interesting to fishery 

 biologists is the fact that the distribution of the several 

 forms is genetically controlled. In the serum esterase 

 system in skipjack tuna, six phenotypes commonly occur, 

 resulting from various combinations of three main types of 

 serum esterase. If the proportions of each of these six 

 types in fairly large samples differ consistently between 



populations, then those jjopulations can be said to be 

 genetically distinct. 



On the basis of the serum esterase system, Fujino has 

 found that skipjack tuna in the Pacific Ocean can be split 

 into two poi)ulations: one found near the Japanese i,slands 

 and to the south of them in the Marianas and Palau, and 

 another found off the west coast of Baja California, Tahiti, 

 the Line Islands, and Hawaii. And what made the samples 

 taken by the Jajiaiicse fishermen operating between the 

 date line and JaiKin so important, was that when propor- 

 tions of six esterase forms are counted these samples 

 proved to be of fish not from the nearby western Pacific 

 group, but indistinguishable from tho.se of the eastern and 

 central Pacific. Thus a possible boundary between the 

 populations lies far to the west of the inlcrnalional date 

 line, a fact not known before. 



THE SHRIMP RESOURCE 



Recent studies of the shrimp and bottom fish resources 

 of the Hawaiian Islands showed that a possible commercial 

 venture could be initiated for a low volume specialty mar- 

 ket. Oceanic islands, such as the main ones in the Hawaiian 

 chain, are characterized by narrow underwater shelves. 

 Water more than a mile deep can be found within 6 miles 

 of the Hawaiian shore. Thus a large resource of animals 

 that live on or near the bottom in .shallow water could 

 scarcely be expected in the Hawaiian Islands. 



In an early investigation of these demersal resources of 

 the Hawaiian Islands, a study of the fauna to a depth of 

 about 5,000 feet was made in 1902 on the Albdtross, re- 

 search vessel of the U.S. Fi.sh Commission (a predecessor 



of the Bureau of Commercial Fisheries). According to 

 Howard O. Yoshida, Laboratory scientist who headed the 

 trawling surveys in 1967 and 1968, most of the published 

 records of deep-water fishes and invertebrates from Ha- 

 waii are based on specimens caught on the Albatross survey. 

 Between October 1967 and May 1968 the Laboratory in 

 Honolulu, in cooperation with the Hawaii Institute of Ma- 

 rine Biology, University of Hawaii, made three exploratory 

 bottom trawling cruises on the Townsend Cromwell (fig. 

 1.5). The strategy adopted in the surveys was first to 

 locate the most promising areas on the basis of depth 

 data and bottom notations on navigational charts, and then 

 make detailed echo-sounding transects in those areas. Bot- 



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