FISHERY BULLETIN: VOL. 69, NO. 4 



conditions. I adjusted for this by using a method 

 suggested by Gulland (1961) whereby effort is 

 an average of the current year's effort {Xi) and 

 the effort from some number of preceding years 

 (Xi-i, Xi^2, Xi-i ), depending on the av- 

 erage number of years a year class is available 

 to the fishery. I used for North Atlantic alba- 

 core an average of effort in the current year 

 and the two preceding years: 



X = 



Xi + Xi-i + X- 



The results (Figure 10) show that in the North 

 Atlantic there has been only a slight decline in 

 CPUE over the history of the fishery. When 

 actual catch and effort data are plotted on the 

 predicted yield curve, only in 1964 did yield ex- 

 ceed even 50 '^r of the predicted maximum. It 

 is likely, therefore, that an analysis using an 

 equilibrium-yield model for the North Atlantic 

 albacore longline fishery is not feasible since the 

 population abundance (as represented by 

 CPUE) has apparently not declined sufficiently 

 to effectively describe the dynamics of the stock 

 in relation to fishing. Consequently, maximum 

 sustainable yield from the North Atlantic long- 

 line fishery is not estimable at this time. It 

 appears, however, that increased fishing will re- 

 sult in increased yield with no major decline in 

 CPUE. 



SOUTH ATLANTIC 



The albacore longline fishery in the South 

 Atlantic is concentrated in three main areas 

 (Figure 8). During the late 1950's and early 

 1960's fishing was excellent in area C and fishing 

 effort increased rapidly to a peak of about 22 

 million hooks in 1964. CPUE declined sharply, 

 however, from a high of 10.0 albacore per hun- 

 dred hooks, and in recent years has stabilized at 

 about 2Jy. In 1961 the Japanese fished in area D 

 for the first time, and this area quickly became 

 the major producer of albacore in the South 

 Atlantic. Fishing is excellent almost year round, 

 and CPUE has remained fairly constant at about 

 8.0 albacore per hundred hooks over the past 5 

 years. Area E has recently developed as a good 



20 40 60 80 



FISHING EFFORT (MILLIONS OF HOOKS) 



Figure 10. — Linear relation between catch per unit of 

 effort (CPUE) and effort (upper panel) and theoretical 

 equilibrium yield curves (lower panel) predicted for the 

 North Atlantic albacore longline fishery. The effort 

 figures in the upper panel are means of the current 

 year's effort and the two preceding year's effort. Effort 

 figures in the lower panel are actual yearly values. 



albacore area although effort is still relatively 

 low. 



I combined catch and effort data from the 

 Japanese, Chinese, and Korean longline fishery 

 and plotted CPUE against effort in the same 

 manner as for the North Atlantic (Figure 11). 

 The decline in CPUE is more pronounced than 

 for the North Atlantic. The yield curve indi- 

 cates a theoretical maximum yield of about 

 1,100,000 albacore from an effort of about 32 

 million hooks. This yield was equaled in 1964 

 and surpassed in 1966 and 1968 with an effort 

 of about 25 million hooks. 



The South Atlantic albacore fishery has under- 

 gone two rather sei^arate and distinct phases. 

 The first phase was from 1956 to 1964 when 

 most fishing effort was in area C. This area 

 produced excellent catches for several years; 

 then catch rates declined rapidly. In 1965 the 

 Japanese increased their fishing in area D in 

 response to excellent catch rates in this area. 



852 



