Pelagic Fur Seal Investigations, 1965 



By 



CLIFFORD H. FISCUS, Wildlife Biologist, and 

 HIROSHI KAJIMURA, Fishery Biologist 



Bureau of Commercial Fisheries 



Marine Mammal Biological Laboratory 



Seattle, Wash. 981 15 



ABSTRACT 



Pelagic fur seal research as required by the Interim Convention on Conserva- 

 tion of North Pacific Fur Seals was conducted off Washington (2-24 April) and off 

 California (11 April to 23 June). One hundred forty- seven fur seals ( Callorhinus 

 ursinus ) were taken off Washington and 269 off California, Off Washington, seals 

 were most numerous near Grays Harbor in mid-April. Off California, seals were 

 concentrated off Monterey fronn late April to early June and near Cordell Bank west 

 of Pt. Reyes in April and early May. Observation or transect lines extending from 

 10 to 80 miles offshore were established between Bodega Head and Pt, Sur, Calif., 

 at 20-mile intervals, to study distribution and migration. Seals were most abundant 

 from 30 to 40 miles offshore. Of the 387 female seals taken, 44 percent were preg- 

 nant; the youngest pregnant females were 5 years old, A squid, Moroteuthis robusta , 

 is reported for the first time as fur seal food. By volume, the principal species of 

 fish eaten by seals off California was Merluccius productus and off Washington was 

 Engraulis mordax . 



INTRODUCTION 



The United States has engaged in pelagic 

 research on fur seals intermittently since 

 1883. In that year James G. Swan (1883), U.S. 

 Fish Commission, worked on seals brought 

 into Neah Bay, Wash., by Indian sealers. 



Charles H. Townsend (1898) and A. B. 

 Alexander (1892)' of the U.S. FishConnmission 

 began pelagic studies in 1892 fronn the U.S. 

 Revenue Marine Cutter Corwin in the Bering 

 Sea and Gulf of Alaska. Townsend, Alexander, 

 and Frederic A. Lucas continued ocean inves- 

 tigations in 1896 under a commission headed 

 by David Starr Jordan (Jordan, 1 899). Between 

 1896 and 1952 no large-scale investigations 

 were carried out. Observations and collections 

 made by many observers during this time are 

 summarized by Taylor, Fujinaga, and Wilke 

 (1955). 



As part of cooperative investigations by 

 Canada, Japan, and the United States in 1952, 

 Victor B, Scheffer collected seals offshore 



'In Records of the United States Fish Commission, 

 prepared by General Services Administration, The National 

 Archives, Washington, D,C., 1953 (Record Group 22), 

 (Manuscript report by A. B, Alexander concerning fur 

 seals, 1892, 23 p.) 



from California to Alaska (Taylor, Fujinaga, 

 and Wilke, 1955). Wilke and Kenyon (1957) 

 studied food habits of fur seals in the Bering 

 Sea in 1955. 



Pelagic research under the Interim Conven- 

 tion on Conservation of North Pacific Fur 

 Seals began in 1958. Mennbers of the Conven- 

 tion are Canada, Japan, the U.S.S.R., and the 

 United States. 



One objective of the Convention is to deter- 

 mine "what the relationship is between fur 

 seals and other living marine resources and 

 whether fur seals have detrimental effects on 

 other living marine resources substantially 

 exploited by any of the Parties, and, if so, to 

 what extent." The first part of this objective 

 will probably never be entirely satisfied, and 

 though we have acquired detailed knowledge 

 about the food of fur seals, the effects result- 

 ing from their feeding are obscure and likely 

 to remain so indefinitely. 



Other research required by the Convention 

 is partly completed. The migration routes of 

 fur seals and their wintering areas are gen- 

 erally known, but relatively little information 

 is available on far-offshore distribution and 

 the movements of seal pups during their first 

 months at sea. The age and sex of seals mov- 

 ing and feeding off the coast during different 



