U.S. DEPARTMENT OF COMMERCE 

 C. William Verity, Secretary 



NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION 

 William E. Evans, Under Secretary for Oceans and Atmosphere 



NATIONAL MARINE FISHERIES SERVICE 

 James W. Brennan, Assistant Administrator for Fisheries 



Fishery Bulletin 



The Fishery Bulletin carries original research reports and technical notes on investigations in fishery science^ engineering, and economics. 

 The Bulletin of the United States Fish Commission was begun in 1881; it became the Bulletin of the Bureau of Fisheries in 1904 and 

 the Fishery Bulletin of the Fish and Wildlife Service in 1941. Separates were issued as documents through volume 46; the last document 

 was Na 1103. Beginning with volume 47 in 1931 and continuing through volume 62 in 1963, each separate appeared as a numbered bulletin. 

 A new system began in 1963 with volume 63 in which papers are bound together in a single issue of the bulletin instead of being issued 

 individually. Beginning with volume 70, number 1, January 1972, the Fishery Bulletin became a periodical, issued quarterly. In this form, 

 it is available by subscription from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. It is also 

 available free in limited ntunbers to libraries, research institutions, State and Federal agencies, and in exchange for other scientific 

 publications. 



SCIENTIFIC EDITOR, Fishery Bulletin 



Dr. Andrew E. Dizon 



Southwest Fisheries Center La Jolla Laboratory 



National Marine Fisheries Service, NOAA 



P.O. Box 271 



La Jolla, CA 92038 



Editorial Committee 



Dr. Jay Barlow 



National Marine Fisheries Service 



Dr. William H. Bayliff 



Inter-American Tropical Tftma Commission 



Dr. George W. Boehlert 

 National Marine Fisheries Service 



Dr. Bruce B. CoUette 



National Marine Fisheries Service 



Dr. Robert C. Francis 

 University of Washington 



Dr. James R. Kitchell 

 University of Wisconsin 



Dr. William J. Richards 

 National Marine Fisheries Service 



Dr. Tim D. Smith 



National Marine Fisheries Service 



Mary S. Fukuyama, Managing Editor 



The Fishery BvMetin (ISSN 0090-0656) is published quarterly by the Scientific Publications Office, National Marine Fisheries Service, 

 NOAA, 7600 Sand Point Way NE, BIN C15700, Seattle, WA 98115. Second class postage is paid in Seattle; Wash., and additional offices. 

 POSTMASTER send address changes for subscriptions to Fishery Bulletin, Superintendent of Documents, U.S. Government Printing 

 Officci Washington, DC 20402. 



Although the contents have not been copyrighted and may be reprinted entirely, reference to source is appreciated. 



The Secretary of Commerce has determined that the publication of this periodical is necessary in the transaction of the public business 

 required by law of this Department Use of funds for printing of this periodical has been approved by the Director of the Office of Manage- 

 ment and Budget 



