(O 



O 



X 



o 



I- 

 < 



m 



< 



IT 

 O 



1950-51 



1960-61 



1965-66 



1970-71 



CRAB SEASON YEARS 



Figure 1. — Crab landings, in millions of pounds, for 

 Washington, Oregon, northern California (Eureka area), 

 and San Francisco area, by season, for the 25-yr period 

 1947-48 through 1971-72. 



seasons. The latter resulted from high catches 

 in newly exploited crab grounds off Brookings, 

 Oreg. (Pacific Marine Fisheries Commission, 

 1960, 1961). Perhaps the high catches in north- 

 ern California during the same period were 

 due to exploitation of these or other newly dis- 

 covered beds. 



The coastwide trend from 1963-64 until 

 1969-70 has been one of steadily improving 

 catches climaxing in record catches for nearly 

 all areas. What might have been termed a col- 

 lapse of the Eureka and San Francisco region 

 fisheries in 1962-63 and 1963-64 has become a 

 reality for the San Francisco area ports. All 

 other areas recovered from this depressed 

 period. 



Figure 2 shows the summed upwelling index 

 values for lat. 48°N, 45°N, and 42°N. The units 

 of the indices are cubic meters of water upwelled 

 per second per 100 m of coastline. Absolute 

 values of the indices were always lowest in 

 Washington, intermediate in Oregon, and high- 

 est in northern California. 



A uniform coastwide pattern of annual var- 

 iability of the upwelling index is apparent in 

 all three states, over the periods of 1948-57 

 and 1960-71. No coastwide trend is apparent 

 for the summers of 1958 and 1959. Deviations 

 from the agreement pattern do appear in other 

 years (1949, 1954, 1961, 1966, 1969, and 1970) 

 but they are small and probably insignificant. 



800 



X 600 



Q 



z 



e 400 



UJ 



a. 



3 



200 



' ' ' I ' ' ' ' I 

 •■ -• 42»N, N CALIF 



 -o 45°N, OREGON 



* • 48°N. WASH. X 



"1 I I I — I — p — I — I — I — 



/ \ 



' ^ I ^ I \ 



I ^ I ^ \ 



' / . ' * 



•,  ■. . \ / K ' \ 



1955 I960 1965 



UPWELLING YEARS 



1970 



Figure 2. — Bakun's upwelling indices for Washington, 

 Oregon, and northern California. The units of the index 

 are cubic meters of water upwelled per second per 100 m 

 of coastline. The northern California values represent 

 summed March through September index values calcu- 

 lated by Bakun for lat. 42 °N. The Oregon data were 

 summed over April through September at lat. 45 °N and 

 the Washington data were summed over May through 

 September at lat.48°N. 



Figures 3, 4, and 5 are time-series plots of 

 upwelling index and crab catch, in Washington, 

 Oregon, and northern California, respectively. 

 Washington winter crab catches are plotted 

 opposite the preceeding summer's upwelling 

 index (V2-yr lag). Oregon and northern Cali- 

 fornia crab catch data are plotted with a IV2 yr 

 lag (upwelling plotted opposite catch of the 

 winter V-Zi yr later). Reasons for the differing 

 lag times will be discussed later. 



The Oregon data (Figure 4) follows trends 

 in upwelling index values remarkably well, 

 since 1955. Notable is the weak upwelling pe- 

 riod of 1960-63 followed IV2 yr later by the 

 poorest crab catches in 1961-62 through 1964- 

 65, and the high values of the upwelling index 

 in 1964-68 followed IV2 yr later by record 

 and near-record crab landings in 1965-66 

 through 1970-71. The record catch of 1970-71 

 would seem anomalous but very likely reflects 

 the long-term effect that prolonged periods of 

 very strong upwelling can have on the popula- 

 tion. The three record years of upwelling in 

 1965-67, as well as strong upwelling in 1968, 

 may have generated enough food reserves to 

 keep the crab population supplied with a food 

 surplus, thus contributing to a good catch 2V2 

 vr later. 



905 



