tons (Ahlstrom 1968). Ahlstrom's estimate is considerably 

 higher than MacCall et al.'s (1980), who estimated the current 

 spawning biomass to be 1 to 2 million tons, with 1.5 million 

 tons as the working estimate. 



Sablefish. — The sablefish is distributed throughout the 

 North Pacific Ocean from the Bering Sea south to northern 

 Baja California and along the Asian coast from Kamchatka 

 southward to the northeastern coast of Japan. This species was 

 among the principal prey of fur seals taken in waters off Cali- 

 fornia during May (Fig. 7) and it was also important to fur 

 seals in areas north of California (Table 3). In waters off Cali- 

 fornia, small immature sablefish are common in inshore 

 waters, particularly in spring and summer. Fur seals, however, 

 vacate the area about this time to return to the Pribilof Is- 

 lands. Sablefish generally move to deeper water as they in- 

 crease in age and size with adults inhabiting the deeper waters 

 along the continental slope and beyond throughout much of 

 the eastern North Pacific Ocean. 



Sablefish occupy a wide range of depths, with adult fish 

 showing daily diurnal movement from depths below 150 m. 

 Juvenile fish inhabit the near surface and coastal waters to 

 depths < 150 m (Fig. 25). Sablefish were located in greatest 

 numbers between 366 and 823 m off the coasts of Oregon and 

 Washington (Heyamoto and Alton 1965). 



Although there are no biomass estimates for sablefish off 

 California, this species is the most abundant roundfish taken 

 by otter trawlers; Frey (1971) reported that it could withstand 

 a greater rate of exploitation. Low et al. (1976) 12 reported that 

 the relative distribution of exploitable sablefish biomass for 

 the California- Vancouver and Bering Sea Region is 13% each 

 — the Aleutian Region 7%, with the highest concentration 

 located in the Gulf of Alaska contributing 67%. 



Sablefish spawn from December to April, with peak activity 

 occurring during January and February in deep water (250-750 

 m). There is no evidence of a spawning migration. They are 

 relatively fast growing, attaining an average length of about 33 

 cm at the end of their first year and enter the fishery near the 

 end of their second year when about 43 cm in length (Frey 

 1971). Fur seals prey on the smaller sablefish before they move 

 into deeper water as mature fish. 



Oceanic squid. — The oceanic squids Onychoteuthis sp. and 

 O. boreulijaponicus were combined in this report for Califor- 

 nia (shown as Onychoteuthis sp. in Figure 7) as important 

 food of fur seals during January and February. According to 

 Young (1972), O. borealijaponicus is the only species found 

 here, O. banksii replacing it in subtropical and tropical waters. 

 Okutani and McGowan (1969) reported that O. banksii was 

 the fifth most abundant squid in the CalCOFI survey area and 

 was present throughout the entire California Current System. 

 The occurrences of this squid in stomachs of fur seals taken 

 off California are shown in Figure 26. 







+ ♦ 









* , t 





+ 





X 



"Eureka 



♦ + / 







O 



4 



X V 





\ < 









\ * 





\ ° 





/ * 





( * 









\ 7 







+ 





♦* 











* »* , %t } 





J*V * V 





* 4H-* + \ 





. +♦+ * > Monterey 





♦ + + \ 





*\ \ 









* * C Pi. Conception 





~ *v/ oCa 





. 





. **♦ " 







"Low, L. L., G. K. Tanonaka, and H. H. Shippen. 1976. Sablefish of the north- 

 eastern Pacific Ocean and Bering Sea. Processed rep., 115 p. Northwest and 

 Alaska Fish. Cent., Natl. Mar. Fish. Serv., NOAA, 2725 Montlake Blvd. E., Seat- 

 tle, WA 981 12. 



Figure 26. — Locations off California where 448 northern fur seals were collected 

 whose stomachs contained Onychoteuthis sp., 1958-66. 



Adult 

 (3 lo 20+ years) 



,000 -547 

 1,200 -fJ6 



Figure 25. — But hymeiric distribution of sablefish (from Low et al. text footnote 



12). 



Bering Sea 



The Bering Sea marine fish fauna is made up of about 300 

 species of fish representing about 40 families (Quast and Hall 

 1972; Wilimovsky 1974). From this group, fur seals are known 

 to prey on fish species from 17 families. Some have occurred 

 only rarely in the stomachs of sampled seals while some species 

 have occurred many times because of their abundance, migra- 

 tory patterns, and spawning and feeding patterns — which 

 coincide with the distribution, migratory, and feeding habits, 

 of fur seals (Table 10). Oceanic squids representing three gen- 

 era from the family Gonatidae have also been identified in 

 stomachs of fur seals from the eastern Bering Sea (Table 10). 



20 



