96 REPORT OF THE SECRETARY OF COMMERCE 



respects. They provided for the prohibition of clearance for area 3, 

 when the boats ah-eady cleared for fishing were sufficient to catch 

 the limit allowed, and" for the setting of a subsequent date of last 

 fishing. They also provided for the retention and sale of a limited 

 proportion of halibut caught incidentally to fishing for other species 

 with set lines in areas closed to halibut fishing. Other changes af- 

 fected the dates of beginning and termination of the winter closed 

 season. 



The Commission recorded the catch from each area, forecast and 

 announced tlie date of attainment of each area limit and closed the 

 areas accordingly. It issued new regulations on February 26, 1938, 

 changing the regulations of August 1937 by increasing the catch 

 limits in areas 2 and 3 one million pounds each and prohibiting the 

 use of set nets for the capture of halibut. 



The investigations necessary for the fulfillment of the purposes 

 of the treaty included the collection and analysis of the current sta- 

 tistical and biological data, which are necessary for tlie evaluation 

 of the success of regulation and for continued intelligent control of 

 the fishery. 



Further improvement in the condition of the stocks of halibut 

 was revealed by the investigations. In area 3, which includes the 

 grounds north and west of Cape Spencer, Alaska, the catch per unit 

 of effort was 19 percent greater than in the previous j^ear and 73 

 percent greater than in 1930, the year when the abundance of halibut 

 reached its lowest ebb. The catch per unit in area 2, which includes 

 the grounds between Cape Spencer and Willapa Harbor, Wash., was 

 slightly greater than in 1936, and 74 percent greater than in 1930. 



Extensive market measurements showed that the reduction in the 

 rate of capture of the fish resulting from regulation had produced 

 a further small increase in the size of the fish landed, which, in con- 

 junction with the general increase in abundance, indicated an in- 

 crease in the spawning stock on the grounds from the previous year. 

 Analysis of the catches of spawn taken in area 2, by means of quan- 

 titative net hauls made from a chartered vessel in the winter of 

 1936-37, showed an increase over the previous three winters. The 

 net hauls were repeated in the "winter of 1937-38 and the results are 

 in process of analysis. 



Four publications were issued during the year, one report and 

 three circulars. The report, "Theory of the effect of fishing on the 

 stock of halibut," dealt with the theory that explains the past decline 

 of the fishery and its gradual recovery as a result of present regulation. 

 The circulars "Why are there separate areas?", "Halibut tagging 

 experiments," and "The early life history of the halibut," explain in 

 simple form the results of the investigations of the Commission and 

 their bearing on the regulation of the fishery. 



The investigations of the Commission continued to explain the 

 changes taking place in the stocks of halibut on the banks. They 

 prove that the condition of the stocks is still improving, as a result of 

 regulation, and offer new assurance of the ultimate success of the 

 Commission in rebuilding the stocks of halibut to a higher level of 

 productiveness. 



