FISHERY BULLETIN; VOL. 83. NO. 3 



our experience that much of the fishing effort in 

 these blocks is in the two depth regimes discussed 

 here. Thus we believe the figures in Table 5 are 

 reflective of the relative fishing effort between 

 blocks. 



The data indicate that Anacapa (blocks 684, 707) 

 and eastern Santa Cruz (blocks 685, 708) were in- 

 deed among the most heavily fished areas. On the 

 other hand, the westernmost section of San Miguel 

 (block 690), with generally the largest fish size fre- 

 quencies, was also fished intensively. There are other 

 discrepancies between fishing pressure and size fre- 

 quencies (Fig. 2). Though block 686 (mid-Santa Cruz) 

 is only moderately fished, Sebastes serranoides mean 

 lengths (0-36 m) are similar to those of the more 

 heavily impacted areas to the east. The drop in S. 

 mystinus length (0-36 m) begins in block 687 

 (western Santa Cruz), another moderately fished 

 site. In fact, both S. mystinus and 5. caurirms taken 

 in adjacent block 710 (eastern Santa Rosa) are larger 

 than block 687, even though more fishing took place 

 in block 710. This is not to imply that differences in 

 fishing effort between areas may not play a role. 

 Rather, we believe that the response to temperature 

 by these species is also important. 



The marine fauna of the Southern California Bight 

 is notable for its temporal fluctuation. Studies of 

 both fossil (Fitch 1969) and present day records 

 (Hubbs 1948; Radovich 1961; Stephens et al. in 

 press) indicate considerable fluctuation in relative 

 abundance between temperate and tropically derived 

 species. Much of this faunal variability is due to 

 unstable water temperature patterns over the con- 

 tinental shelf. Weakening of the California Current 

 allows for a northerly flow of subtropical water and 

 its associated fauna. During periods of strong 

 California Current, temperate forms increase in 

 abundance. Data for this paper were gathered dur- 

 ing the end of a cold cycle (1976) and the beginning 

 of a warm one (which continues to the present - 

 1984). 



Juveniles and adults may move with insurgent 

 water masses. This is particularly true of such 

 pelagic or semipelagic species as Seriola lalandei, 

 Sphyraena argentea, Sarda chiiiensis, and Scomber 

 japonicus. All occur about Santa Cruz and Anacapa 

 Islands (and throughout much of the Southern 

 California Bight) in warmwater periods. During the 

 strong 1983 El Nino, the tropical yellowfin tuna, 

 Thunrms aibacares, and skipjack tuna, Euthynnus 

 pelamis, ventured far north of their usual range up 

 to Santa Cruz Island. Even relatively sedentary 

 species may follow currents. The finescale trigger- 

 fish, Batistes polylepis, was an early migrant into 



southern California at the beginning of the warm 

 cycle in the mid-1970's and remains relatively com- 

 mon about inshore reefs as far north as Santa 

 Barbara. 



Larval transport and subsequent species recruit- 

 ment may be affected by changes in water masses. 

 During 1983, a number of warm- temperate species 

 (including rock wrasse, Halichoeres semicinctus; 

 garibaldi, Hypsypops rubicunda; spotted sandbass, 

 Paralabrax maculatofasciatics; Seriola lalandei; 

 Sphyraena argentea; salema, Xenistius califomien- 

 sis) recruited off Santa Barbara, well north of their 

 usual range.* Similar unusual northerly recruitment 

 of Semicossyphtcs pulcher and Catalina goby, 

 Lythrypmcs dalli, occurred during the same period 

 off central California.^ 



Young of-the-year of warm-temperate species 

 have recruited north of their usual range in past 

 warm periods, e.g., 1957-58 (Radovich 1961). In 

 many cases, such as that of the opaleye, Girella 

 nigricans, off Monterey, only a single year class (i.e., 

 1958) survives, leading in succeeding years to 

 populations of similar-sized individuals.^ During the 

 early 1970's, we observed that the population of 

 Semicossyphus pulcher around San Miguel, was com- 

 posed entirely of large individuals. Perhaps these, 

 too, were the survivors of a successful year class dur- 

 ing the 1957-58 warmwater period. 



Conversely, during the years of strengthened 

 California Current, species more representative of 

 central California recruit south. The early 1970's 

 were a relatively cool water period and temperate 

 species such as kelp greenling, Hexagrammos deca- 

 grammus; Ophiodon elongatus; Sebastes mystinus; 

 and S. serranoides young-of-the-year successfully 

 recruited in southern California (Stephens and Zerba 

 1981; Stephens et al. in press). These maintained 

 themselves in the locally cool habitat at the head of 

 Redondo Submarine Canyon, well after they disap- 

 peared from much of the Bight. Water temperature 

 is also responsible for the continuation of long-term 

 temperate species remnant populations on the 

 southern sides of several Baja California points 

 (Hubbs 1960). Here, upwelling water creates suit- 

 able conditions for a number of temperate species, 

 which are either missing from, or found in deeper 

 water off of, southern California. 



*S. Anderson and .1. McCullauj;;h, Marine Science Institute, 

 University of California, Santa Barbara, CA 93106, pers. commun. 

 November 1983. 



*D. Miller, California Department of Fish and Game, 2201 Garden 

 Road, Monterey, CA 93940, pers. commun. January 1977. 



^F. Henry, California Department of Fish and Game, 2201 

 Garden Road, Monterey, CA 93940, pers. commun. November 

 1983. 



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