the Gulf of Alaska during May. The northbound migration 

 begins March- June, first in the southern limits of the range off 

 California and proceeding past Washington in April and May, 

 the Gulf of Alaska in May and June, and westward into the 

 Bering Sea in June. In June, fur seals are scattered throughout 

 the North Pacific Ocean. Fur seals are in the eastern Bering 

 Sea and on or near the breeding islands of St. Paul, St. 

 George, and Sea Lion Rock (Pribilof Islands) in greatest num- 

 bers during July, August, and September (most age groups of 

 both sexes). 



In the eastern North Pacific Ocean, any discussion of fur 

 seal distribution at sea refers primarily to females because they 

 represent about 90% of the pelagic catch (with some variation 

 by time and area). Older females (age 5 yr and older) are gen- 

 erally more abundant off California than off Washington, 

 while the younger seals are not fully represented (Append. 

 Figs. A-l to A-10). Females of all ages (and young males 1-4 yr 

 old) are found in the Gulf of Alaska and the eastern North 

 Pacific Ocean during winter and spring. Only the younger im- 

 mature males (ages 1-5 yr) have been found south of Alaskan 

 waters with a few exceptions. Nearly all of the older males win- 

 ter in Alaskan waters — primarily in the Gulf of Alaska, north 

 and south of the eastern Aleutian Islands, and probably in the 

 Bering Sea. The catch of males diminished south of lat. 46°N 

 (Washington-Oregon border) as shown by summaries of the 

 monthly age and sex composition in Appendix Figures A-l to 

 A-10. Of 3,612 fur seals taken off California, only 2% or only 

 56 animals were males of ages 1-5 yr and only one seal was 5 yr 

 old. The seals on which these percentages were based were 

 taken prior to 1967, and the San Miguel Island males would at 

 that time not have contributed to the offshore population. No 

 attempt has been made to verify the distribution of older males 

 because poor weather conditions during late autumn, winter, 

 and early spring in the Gulf of Alaska and Bering Sea would 

 severely curtail vessel operations and reduce sightings or 

 catches. 



Fur seals congregate in tight social groups on land but at sea 

 they are often solitary. Solitary seals predominated in all areas 

 (Appendix Table A-l). The frequency of solitary seals was 

 highest in the Bering Sea (38-68%) where seals are more abun- 



dant during the breeding season. Off California, solitary seals 

 represented 30 to 50% of the total sightings, whereas off 

 Washington they comprised 30-64% . Larger groups of up to 

 20 seals have on occasion been sighted usually during spring 

 migration but groups of this size are unusual. A few groups of 

 seals numbering more than 20 have been seen off Washington 

 and California when they were actively feeding on large 

 schools of prey. 



The subarctic water mass fluctuates seasonally — north in 

 summer, south in winter. Seasonal and annual variations in 

 temperature, salinity, dissolved oxygen, and water movement 

 patterns occur on a worldwide basis. The role of such ocean 

 currents and other oceanic factors in the distribution and 

 migration of fur seals in the eastern North Pacific Ocean has 

 yet to be examined systematically; however, some data are 

 available. During our 1958-74 studies, the largest numbers of 

 fur seals were collected where surface water temperatures 

 ranged from 10° to 14°C off California, 7°-12°C off Washing- 

 ton, 5°-9°C in the Gulf of Alaska, and 8°-10°C in the Bering 

 Sea (Kajimura 1980 2 ). Upwelling of water from the depths is 

 an important oceanic and coastal process which occurs when 

 the surface layer is transported offshore (due to the stress of 

 wind parallel to the coast on the sea surface) and is then re- 

 placed by nutrient-rich water from below. The western coast 

 of North America is among the world's major upwelling 

 regions. Here, upwelling probably influences productivity and 

 concentration of primary producers and zooplankton. This in 

 turn influences the distribution and recruitment of fish stocks 

 which become available to the fur seal, and ultimately the dis- 

 tribution of seals because they winter and feed off the western 

 coast of North America. 



'Kajimura, H. 1980. Distribution and migration of northern fur seals (Callo- 

 rhinus ursinus) in the eastern Pacific. InH. Kajimura, R. H. Lander, M. A. Perez, 

 A. E. York, and M. A. Bigg, Further analysis of pelagic fur seal data collected by 

 the United States and Canada during 1958-74, Part 1 , p. 6^»3. Unpubl. rep. Natl. 

 Mar. Mammal Lab., Northwest and Alaska Fish. Cent., Natl. Mar. Fish. Serv., 

 NOAA, 7600 Sand Point Way NE., Seattle, WA 981 15. 



BERING 

 SEA 



'V •<"* 



;-,-,■-,= 130 cue mo ooe iso ooe 



Figure 2.— Fur seal sightings in Ihe North Pacific Ocean by Japan, Canada, and (he United States, 1955-79. 



