Woodbury: Reduction of growth in otoliths of Sebastes entomelas and 5. flavidus 



687 



growth of widow rockfish in this area as 

 compared with growth from more north- 

 erly distributed populations. This may be 

 related to diet because more northerly dis- 

 tributed populations consume more fish 

 and euphausiids, whereas populations in 

 the south feed more on gelatinous zoo- 

 plankters. Lorz et al. (1983) reported the 

 diet of yellowtail rockfish in Queen Char- 

 lotte Sound comprised both fish and eu- 

 phausiids, whereas off Washington it com- 

 prised mainly euphausiids. Pereyra et al. 

 ( 1969) found that fish dominated the diet 

 of both yellowtail and widow rockfish col- 

 lected near Astoria Canyon, off northern 

 Oregon. Brodeur and Pearcy ( 1984) noted 

 that yellowtail rockfish preyed on a diverse 

 assemblage, dominated by euphausiid, 

 fish and squid, depending on the season. 

 Adams (1987) reported that widow rock- 

 fish collected off northern California fed 

 primarily on gelatinous zooplankters. At 

 Cordell Bank, during late fall, winter, and 

 in years of reduced productivity (e.g. 1983), yellow- 

 tail rockfish have been found to feed primarily on 

 gelatinous zooplankton, which has a lower nutri- 

 tional value than their preferred diet of euphausiids 

 (MacFarlane'^). Owing to the lack of upwelling and 

 reduced productivity during 1983, these fish were 

 probably forced to feed on less nutritional prey. Al- 

 though lacking stomach analysis data for 1983, 

 Lenarz and Wyllie Echeverria ( 1986) found a signifi- 

 cant reduction in visceral fat of yellowtail rockfish 

 collected at Bodega Bay during 1983 as compared 

 with 1980, a "normal" year. 



An assumption of this study is that the widow and 

 yellowtail rockfish sampled during this study did not 

 migrate to less productive waters during 1983 and 

 then return. Most species within the Sebastes genus 

 spend their adult life within a relatively small area 

 (Stanley et al., 1994). Both widow and yellowtail rock- 

 fish lead an epibenthic schooling existence, inhabit- 

 ing the area above benthic structures. Several tag- 

 ging studies have been conducted on yellowtail rock- 

 fish to study the movement of these fish. Carlson and 

 Haight (1972) noted homing behavior in yellowtail 

 rockfish that were captured and transplanted to dif- 

 ferent areas in Alaska. Pearcy ( 1992) tagged 25 yel- 

 lowtail rockfish on Heceta Bank off central Oregon 

 and noted little displacement during a one-month 

 period. However, Stanley et al. ( 1994) noted displace- 

 ment of several tagged yellowtail rockfish from Alas- 

 kan and Canadian waters after they had been at large 

 for several years. Although no tagging studies have 

 been conducted on widow rockfish, it is worth noting 



MacFarlane, R. B. 1994. 

 Paradise Dr., Tiburon, CA. 



Tiburon Laboratory, 

 Personal commun. 



NMFS. 3150 



