Zeidberg et al : The fishery for Loligo opalescens from 1981 through 2003 



53 



APR CPUE/SOI 



10 12 14 16 -16 -14 -i: -10 



Time lag (months) 



10 12 14 16 



Figure 4 



Time-series analysis: cross-correlation between CPUE and the global climatic indices: Southern Oscilla- 

 tion index (SOI for atmospheric pressure differences between Tahiti and Darwin, A and B) and NIN03 

 (SST anomaly in eastern equatorial Pacific, C and D) for regions OCT (A, C) and APR/MB (B, D). The 

 correlation between CPUE and N1N03 is greater than the correlation between CPUE and SOI in both 

 regions. CPUE lags NIN03 by 9-11 months in APR and 4 months in OCT. Thus, the effects of an El 

 Nifio event cause declines in CPUE for Loligo opalescens in Southern California 4 months later and 

 in Monterey Bay 9-11 months later (long arrows). High correlation coefficients at a 10-month lag in 

 Southern California (OCT) may be due to a second generation of market squid responding to changes 

 in SST (shorter arrow). 



all stations were averaged to create the February PDI 

 (Fig. 6 lower right), and this PDI was then compared to 

 the November recruitment of spawning adults (CPUE) to 

 the fishery for the same year. Linear regression was not 

 significant for 1999-2003 {r'- = 0.522. P=0.1683). How- 

 ever, if 1999 was treated as an outlier because it lacked 

 nearshore sampling sites where 76% of the paralarvae 

 were captured subsequently, the regression explains 

 97.8% of the variance, and the F-value of the ANOVA 

 ratio test for this regression is significant, P=0.007 

 (Fig. 7J. From 1992 through 2002, SCB (36.2%) and SM 

 (16.2%) represented nearly half of the landings for the 

 state, and therefore this technique (regression of CPUE 

 on PDI) could apply throughout the state. 



Discussion 



We report landings, effort, and catch per unit of effort 

 for Loligo opalescens in California for 1981-2003. It is 

 important to reiterate that CPUE is an approximation of 

 abundance in the fishery and fails to estimate biomass of 

 squid in California waters. Vessels that attempt to cap- 



