were closely correlated with trends of annual 

 variability of an upwelling index, for the per- 

 iod 1959-71. Poor correlations during the per- 

 iod 1950-58 may have resulted from one or a 

 combination of at least four causes. First, if the 

 fishery were not as intense in these earlier 

 years so that fewer than 90-95% of the avail- 

 able males were taken during a particular 

 season, each seasons catch may be higher than 

 an upwelling index might suggest. Second, 

 if at any time during this period some pre- 

 viously unexploited areas were fished, the state- 

 wide catch data would be higher than one might 

 predict, if one could predict catch. For valid 

 comparison of the raw catch data to environ- 

 mental factors, all crab beds must be "cleaned- 

 out" each year. Third, the upwelling index may 

 be in error during this period. Earlier atmos- 

 pheric pressure data may not be as reliable, or 

 sparce data coverage may have yielded erro- 

 neous indices. A fourth alternative may be that 

 all data are adequate, and that only the extreme 

 conditions influence crabs. Four summers of 

 poor upwelling occurred together from 1960 to 

 1963, followed by five summers of good upwell- 

 ing in 1964-68. Crab catch trends were well 

 established during this period. Prior to the 

 1960's no such persistent trends were found, 

 except with the Oregon data. 



To my knowledge, this study represents the 

 first published attempt to relate Bakun's (in 

 press) upwelling index to fisheries data. Al- 

 though the physical meaning of the index is 

 clear (index value proportional to the volume 

 of water upwelled) it must be remembered that 

 it expresses a monthly mean condition. A low 

 value of the index does not necessarily imply 

 that upwelling-induced production was low in 

 a particular month. For example, if during a 

 particular month, there were 5-day periods of 

 alternating northwest and southwest winds, 

 the upwelling index would be low, but biologi- 

 cal production may still have been reasonably 

 high. In this light then, perhaps only persistent 

 summers of either high or low values have bio- 

 logical meaning. 



Whatever the reasons might be for certain 

 anomalous data points occurring during the 

 period 1950-58, the data from the past 13 yr 

 lend strong support to the hypothesis that up- 



welling is responsible for fluctuations in the 

 crab catches of the west coast, and that the 

 catches show response to the upwelling IV2 yr 

 later off northern California and Oregon, and 

 V2 yr later off Washington. 



Acknowledgments 



This study has been supported by a NOAA 

 Institutional Sea Grant to Oregon State Uni- 

 versity (Contract No. 2-35187). I am indebted 

 to Andrew Bakun of the Pacific Environmental 

 Group, National Marine Fisheries Service, 

 NOAA, Monterey, Calif., for supplying a copy of 

 his manuscript on upwelling indices. I am also 

 indebted to Charles Miller for assistance with 

 the statistical tests, for reviewing this manu- 

 script, and for many helpful discussions. William 

 Pearcy read an earlier manuscript and offered 

 valuable comments. C. Dale Snow of the Oregon 

 Fish Commission, Newport, Oreg., supplied 

 the recent crab catch data. We had several mu- 

 tually informative discussions. 



Literature Cited 



Bakun, A. 



In press. Coastal upwelling indices, west coast of 

 North America. 1946-71. U.S. Dep. Commer., 

 NOAA Tech. Rep. NMFS SSRF-671. 

 Butler, T. H. 



1961. Growth and age determination of the Pacific 

 edible crab Cancer nuigisier Dana. J. Fish. Res. 

 Board Can. 18:873-891. 

 Califorwa Department of Fish and Game. 



1951-71. The commercial fish catch of California 

 for the years 1948-49 through 1970. Calif. Dep. 

 Fish Game, Fish Bull. 84-154. 

 Cleaver, F. C. 



1949. Preliminary results of the coastal crab (Cancer 

 magister) investigation. Wash. Dep. Fish., Biol. 

 Rep. 49A:47-82. 

 Hubbard, L. T., and W. G. Pearcy. 



1971. Geographic distribution and relative abun- 

 dance of Salpidae off the Oregon coast. J. Fish. 

 Res. Board Can. 28: 183 1-1836. 

 MacKay, D. C. G. 



1942. The Pacific edible crab, Cancer magister. 

 Fish. Res. Board Can. Bull. 62, 32 p. 

 Pacific Marine Fisheries Commission. 



1959-70. Status of the Pacific Coast Dungeness 

 Crab Fishery. 12th-23d Annu. Rep. Pac. Mar. 

 Fish. Comm. 



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