Bristol Bay (Dell 1963). Recently, Jaenicke and 

 Bonnett^ completed an extensive study of the 

 foods of some 1,200 seaward-migrating sockeye 

 salmon in Bristol Bay during 1969 and 1970. 

 Most of their samples were taken over deeper 

 waters farther offshore than mine — particularly 

 those off Port Moller. 



The purpose of my study was to document the 

 foods of seaward-migrating sockeye salmon along 

 the main migration route on the north side of the 

 Alaska Peninsula in Bristol Bay, Alaska, during 

 1966 and 1967. Later studies by Straty and 

 Jaenicke (see footnote 1) and Jaenicke and Bon- 

 nett (see footnote 2) show that the areas where I 

 took samples of juvenile sockeye salmon 

 (Kvichak to Port Moller — Figure 1) were indeed 

 along the main migration route in the upper and 

 central parts of the bay (Kvichak to Port Heiden). 

 In lower Bristol Bay, however, my sampling area 

 (Port Moller) was inshore from the usual main 

 migration route. In years when unusually cold 

 sea water temperatures prevail, the main migra- 

 tion route in the lower bay shifts to the warmer 

 inshore waters (Straty 1974). The juvenile sock- 

 eye salmon I sampled in the Port Moller area 

 were taken in a year (1967) when normal temp- 



^Jaenicke, H. W., and M. B. Bonnett. Food of sockeye salmon 

 outmigrants in Bristol Bay, Alaska, 1969-70. Unpubl. manuscr, 

 20 p. Northwest Fish. Cent. Auke Bay Lab., Natl. Mar. Fish. 

 Serv., NOAA, Auke Bay, AK 99821. 



SAMPLING SITES 



1966 • 



1967 A 



-56° 



r^- -^f\ 



Figure l. — Bristol Bay, Alaska, showing locations where 

 juvenile sockeye salmon were collected in 1966 and 1967 for food 

 habit analyses. Samiples in the upper bay (Kvichak and Egegik) 

 were taken in June, and those in the central bay (Ugashik) and 

 lower bay (Port Heiden and Port Moller) were taken from July to 

 September. 



eratures prevailed and were presumably inshore 

 from the path followed by most migrants that 

 year. However, the foods found in 1967 in these 

 inshore waters may reflect what is usually avail- 

 able to the main body of outmigrants in colder 

 years when their path is altered. 



Materials and Methods 



The samples of juvenile sockeye salmon were 

 collected in 1966 and 1967 in the following areas 

 (Figure 1) and times: Kvichak, June of both 

 years; Egegik, June 1966; Ugashik, July and Sep- 

 tember 1966 and August 1967; Port Heiden, July 

 1966 and August 1967; and Port Moller, July and 

 August 1967. All samples were taken during day- 

 light, usually between 1000 and 1900 h. 



In 1966, the juvenile sockeye salmon were col- 

 lected with circular tow nets (2.1 m in diameter) 

 and a small-mesh round haul seine (110 m long 

 by about 7 m deep); in 1967 they were collected in 

 a small-mesh lampara seine (183 m long by about 

 14 m deep). All sampling was done from the 13-m 

 National Marine Fisheries Service vessel Sock- 

 eye. Samples were preserved in 10% Formalin^ 

 solution and processed later. 



I analyzed the stomach contents of 160 juvenile 

 sockeye salmon and all but 16 contained food. 

 These 160 fish represented roughly equal num- 

 bers of individuals from 1-cm size groups ranging 

 from 6- to 13-cm fork length and were from all 

 five areas of Bristol Bay from Kvichak Bay south 

 to Port Moller — a distance of about 320 km. 



The stomach (that portion of the digestive tract 

 from the anterior end of the esophagus to the 

 pylorus) of each specimen was removed, and all 

 food organisms were separated and identified to 

 the lowest taxonomic level practical. All of the 

 food items were air dried overnight at room 

 temperature and weighed to the nearest 0.1 mg 

 the follovdng day. 



The eight major categories of food items: 

 copepods, fish, larval crustaceans, euphausiids, 

 amphipods, insects, miscellaneous crustaceans, 

 and zoofauna, are not mutually exclusive. The 

 least specific categories merely reflect the di- 

 gested condition or incidental importance of a 

 given item, e.g., crustacean remains (recorded as 

 miscellaneous crustaceans) or arachnids (zoo- 

 fauna), which occurred only once. 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



459 



