(1955-64, r = 0.90; 1965-75, r = 0.87) as the peak 

 catches of 1957, 1969, and 1970 closely corres- 

 ponded to sunspot maxima years 1957, 1968, and 

 1969. However, the amplitude of the two 

 phenomena appeared to be asynchronous. The 

 very high sunspot peak of 1957 saw a considerably 

 lower peak crab catch than did the relatively low 

 sunspot peak of 1969. 



Woelke^ suggested that Dungeness crab land- 

 ings were influenced by water temperature during 

 the crabs' larval stage about 4 yr before, with 

 temperatures at that time being inversely corre- 

 lated to landings. We analyzed the relationships 

 between crab catches and the sunspot numbers of 

 4 and 5 yr previous. Correlation coefficients were 

 generated for two crab catch cycles (cycle 1 = 

 1955-64; cycle 2 = 1965-74). The highest correla- 

 tion (cycle 1, r = 0.82; cycle 2, r = 0.95) was 

 between Dungeness crab catches and the sunspot 

 number of 5 yr before (Figure 2, Table 2). The 

 correlation was strongly negative. That is, high 

 sunspot number in a particular year seemed to be 

 a predictor of relatively low crab catches 5 yr 

 hence. 



60 

 a) 

 a 



? 50 



a 



z 



_J *- 



< X 



i CD 30 



< 

 o 



20 



80 100 120 140 

 SUNSPOT NO 



160 180 200 



FIGURE 2.— Mean annual sunspot numbers (SS) of the years 

 1950-69 plotted against total annual landings of Dungeness 

 crabs ( TAL) 5 yr later ( 1955-74). 



T.\BLE 2. — The correlation between commercial Dungeness 

 crab catches and the mean annual sunspot number 5 yr previous 

 (cycle 1 = sunspots of 1950-59, crab landings 1955-64: cycle 2 = 

 sunspots of 1960-69, crab landings 1965-74). 



Period 



df 



^ratio 



Cycle 1 

 Cycle 2 

 Cycles 1 and 2 



0.82 

 .95 

 .69 



1. 8 

 1,9 

 1,23 



16.7 

 87.6 

 20.8 



^0.01 

 <.001 

 <.01 



A number of factors may be involved in the cy- 

 clical C. magister catches. Upwelling, by influenc- 



^Woelke, C.E. 1971. Some relationships between tempera- 

 ture and Pacific Northwest shellfish. Proc. 51st Annu. Conf., 

 Western Assoc. Game Fish Comm., p. 132-135. 



ing food density, may have an effect (Peterson 

 1973). Water temperature and salinity, as well as 

 current pattern may influence larval survival 

 (Lough 1976). Botsford and Wickham (1975) felt 

 that density-dependent biotic factors, such as can- 

 nibalism, might play a part. 



However, as Eddy (1979) stated, in discussing 

 sunspot studies, "We start into the deep waters of 

 uncertainty not from rocks but from the sand, and 

 with statistics our only lifeline." Sunspots, rela- 

 tively dark areas about 2000° K cooler than their 

 surroundings, have been noted for more than 1,500 

 yr (Herman and Goldberg 1978). In the past 200 yr, 

 sunspot activity has been correlated to many 

 planetary processes. Statistical correlations have 

 been made between sunspots and both climatolog- 

 ical and biological phenomena ( Gnevyshev and 01' 

 1977; Pittock 1978). However, increased sunspot 

 activity brings about only slight changes in both 

 magnetic fields and incident radiation levels and, 

 unfortunately, there exists no completely accept- 

 able hypothesis which explains how these slight 

 alterations act on the various processes. 



Thus, whether sunspot activity somehow influ- 

 ences any of the above (including crab catches) is 

 unknown. The work of Southward et al. (1975) 

 suggests that an array of events, including inter- 

 tidal barnacle, Chthalamus sp., numbers, hake 

 and cod trawl catches and pilchard egg densities 

 are correlated, in 11-yr cycles, to sunspot number. 

 There is the strong suggestion in this work that 

 sea surface temperature (also strongly correlated 

 to sunspot activity) may be responsible for the 

 cyclical events. Hence, sunspot activity may be 

 linked to biotic events through the agencies of 

 another level of phenomena (in this case tempera- 

 ture). 



Whether the crab catch and sunspot cycles re- 

 main congruent will have to be seen. Other corre- 

 lations of this nature have proven spurious with 

 time. If the pattern holds, however, annual 

 sunspot number may be a useful predictor of 

 Dungeness crab catch, delineating periods of catch 

 maxima and minima and perhaps predicting catch 

 amplitude, i.e., how many crabs will be taken. 



Acknowledgments 



We would like to thank J. Eddy and R Oilman for 

 enlightening discussions on solar activity. S. Penn 

 and K. Zerba for the illustrations, and S. 

 Warschaw and J. Schulz for typing the manu- 

 script. 



795 



