Pacific Ocean. Shallow and swift, it runs eastward beneath 

 the Equator for about 5,000 miles, carrying as much water 

 as 10,000 Mississippi rivers. 



The ship, Toinisend Cromwell, especially designed for 

 oceanographic and fishery research, was commissioned in 

 .January 1964. By July 1965, she had made 17 oceano- 

 graphic cruises. A vessel 158 feet long, she has a cruising 

 speed of 12.5 knots and can carry 10 scientists and 15 

 officers and crew. She can travel anywhere in the Pacific. 

 Her equipment includes radar, Loran, echo sounders, record- 

 ing pyranometer, and such new and specialized scientific in- 

 struments as a salinity-temperature-depth recorder. 



In February 1964 the newly commissioned vessel sailed 

 from Honolulu on a 20-day oceanographic cruise that took 

 her 960 miles south, 550 miles east, and 240 miles north of 

 Oahu. For the next 16 months, except in August 1964, she 

 set forth on a voyage that followed the same unaltering 

 course. When the last cruise of the series was completed on 

 July 2, 1965, she had sailed 72,000 miles, spent 320 days at 

 sea, collected many thousands of items of data, and proved 

 a significant point : that the work had been well worth 

 doing. 



The waters of the Hawaiian region rank among the most 

 intensively studied in the world. More oceanographic cruises 

 have put forth from Hawaii than any of the other 49 

 states, except California and Massachusetts (the sites of 

 the Nation's largest and oldest oceanographic institutions) 

 and perhaps Washington. The Hawaiian waters are so well 

 known, in fact, that oceanographers are now in a position 

 to progress beyond a broad, essentially static description of 

 average conditions in seasonal and annual terms to analyses 

 of the dynamic processes these conditions refiect. This dif- 

 ference is approximately that between a still photograph 

 and a motion picture. It was the Townsend Cromwell's 

 mission to gather the sequential data on which such studies 

 must be based, and to survey the distribution of physical 



and chemical properties of the ocean with area, depth, and 

 time. 



Although the numbers and distribution of fish must be 

 intimately related to changes in the environment, not until 

 a few decades ago did scientists feel confident enough of 

 their knowledge of the fisheries and the ocean to begin 

 attempts to link the two. But with the prodigious growth 

 of oceanography and fishery biology during the past few 

 years, such efforts have been made in several fisheries 

 located in many areas of the world ocean. In Japan, for 

 example, oceanographers have used their investigations to 

 locate promising areas for the tuna fleet. As another in- 

 stance, our Laboratory in the 1950's found rich accumula- 

 tions of tuna in the equatorial region south of the Hawaiian 

 Islands. The Towimend Cromwell's cruises were undertaken 

 in support of an enterprise of somewhat more sophistica- 

 tion than these pioneering ventures ; they were part of an 

 effort to depict the whole environment as it changes through 

 the year. 



The central Pacific affords a particularly convenient 

 laboratory for such investigations. As has been said, sea- 

 sonal and annual conditions in the surface waters are well 

 known. The climate is equable, so that field studies can be 

 carried on throughout the year and thus comprehensive 

 winter data, so rare in studies of the temperate Pacific, can 

 be readily obtained. The pronounced seasonality and sharp 

 annual fluctuations in the Hawaiian skipjack catch suggest 

 that if the availability of the fish directly reflects changes 

 in their immediate environment, then that availability can 

 be readily monitored from catch statistics. And the partial 

 success of the "aku forecasts" hints that skipjack avail- 

 ability is related to observable dynamic processes in the 

 ocean. 



The Hawaiian Oceanographic Climate 

 In 1962, after analysis of all the data available at that 

 time, oceanographer Gunter R. Seckel of our Laboratory 



27 



