50 



Fishery Bulletin 104(1) 



spectral analysis, and cross correlation time series were 

 made in accordance with Zar (1984). 



Results 



Decadal-regional analysis 



The 22-year fishery data for Loligo opalescens were 

 divided into two periods: 1981-89 and 1990-2003 

 (Table 1) due to a southward shift in the fishery after 

 1989. For the first period (1981-89), 87% of the effort 

 and 66% of the landings were predominantly focused 

 in the MB or APR region, specifically in the southern 

 portion of Monterey Bay. The amount of squid captured 

 in 1981 and 1982 was not matched again in Monterey 

 Bay until 2002. The MB region was the most focused 

 region; 62% of the total catch and 83% of the CPUE 

 came from a very small area (block 526, Fig. 1) — ^just 

 off Monterey harbor. CPUE in this region and time 

 period was low, 5.54 tons/vessel-day (Table 1). SM had 

 4.43% of the landings and 2.2% of the vessels, yielding 



S 120 



100- 

 i 80- 



1 60 

 § 40 

 f 20 

 -> 



.0 



J: Q ii - i - . l .., - :^^ ~<t- 



1981 1983 1985 1987 1989 1991 



1993 1995 1997 1999 2001 2003 



1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 

 Strong Week Week Strong Strong 



El Nino 

 Year 



El Nino La Nina 



Figure 2 



Fi.shery data for Loligo opalescens, summed by year for 1981-2003. (A) 

 landings, (B) vessel days, and (Cl catch per unit of effort (CPUEi by 

 year for Monterey Bay (April [APRI— black circles) and southern Cali- 

 fornia (October [OCT!— unfilled circles) regions. Scale ofy-axis changes 

 between A, B, and C. Note the lack of landings in OCT in 1984 and APR 

 in 1998. following strong El Nino events. 



a CPUE of 14.85 tons/vessel-day. The SB, SCB, and SD 

 areas were similar in the 1980s with landings around 

 9%, vessels at 3%, and CPUEs varying from 18.5 to 

 20.5 tons/vessel-days. The CC area had the smallest 

 percentage of landings (2.5%) and vessels (0.7%), but the 

 highest CPUE (27.4%) — most likely due to squid being 

 hauled as a secondary target species in this region. 

 Few fishermen choose to harvest squid in the central 

 California area because of rough seas and rocky, gear- 

 fouling ocean bottoms. 



The focus of the market squid fishery shifted to 

 southern California in the 1980s and landings sur- 

 passed those of Monterey Bay in 1990 (Fig. 2, Table 1). 

 Whereas vessel-days per year decreased by 17.6% in 

 the MB area, vessel-days increased 20-fold in the other 

 areas. For the period 1990-2003. SM and SB ranked 

 third and fourth for landings and vessel-days because 

 of hauls made on the northern coasts of the Chan- 

 nel Islands and off the Malibu and Redondo Canyons, 

 respectively. CC is the area least targeted, with only 

 5% of landings and vessels. CPUE for this period was 

 26 tons/vessel for all areas except MB, where it was 

 little more than half that at 14 tons/ 

 vessel. CPUE in APR/MB has nearly 

 tripled since 1981-82. CPUE in the 

 OCT region has increased more mod- 

 estly, except in SM. 



Since 1999, annual landings have de- 

 creased in OCT (91,229 tons to 22,180 

 tons) and increased in APR (289 to 

 14,521 tons— with 22,770 tons in 2002, 

 Fig. 2A). Effort has increased as well in 

 the last 23 years (Fig. 2B). With the ex- 

 ception of MB 1981-82, all areas saw the 

 number of vessel-days/month increase 

 until the 1997-98 season. The number of 

 vessel-days has decreased since 1999 — in 

 OCT (4011 to 1573)— and has increased 

 in APR (20 to 978). The average number 

 of days between landings for individual 

 boats in APR (2.3) and OCT (2.1) was 

 not significantly different (^-testg 05,2,, 

 df=977, f-value 0.87, P=0.39). 



There have been increases in CPUE 

 concomitant with gains in experience, 

 and advances in technology have en- 

 hanced the ability of fishermen to lo- 

 cate squid. There has been a "ratcheting 

 up," both in terms of size of vessel and 

 in the amount of sonar (from single to 

 dual frequency [50 to 200 kHz]) used in 

 the competition among fishermen. How- 

 ever, CPUE decreased substantially in 

 all regions in 1984 and 1998, the second 

 years of the two biggest El Niiio events 

 recorded. Milder El Niiio events in 1987 

 and 1992 preceded dips in CPUE val- 

 ues in 1988 and 1993 (Fig. 2C). Aver- 

 age CPUE was calculated for the APR 

 and OCT regions by splitting the data 



