■— 1965 33/3,676=0.97. RETURN 

 — 1964 129/3^76 =3 5% " 

 162/3,676 TOTAL =4.4% " 



FiGUHE 12. — Recovery distribution of .sockeye .salmon 

 tagge<l as .l-age immature lisli at Adak in lOfrl (the 

 arrows deiwcting retiirn.s in ]OC<j are merely drawn for 

 convenience and are not intended to .show migrations 

 during the full year at liberty). 



mimbcrs can he jraincd from ii conservative time- 

 space extrapolation of the average catcli i)or :30- 

 minute seine set; in 1964 a minimum of 0.5 million 

 .l-age sockeye salmon per day passed westward 

 south of Adak Island from late June through late 

 August, or about 30 million of this age group 

 alone. The rate of travel averaged 17 miles (31.5 

 km.) per day for tho.se recovered Iiy the Japanese 

 fleet in 1064. Stomach examinations indicated that 

 the fish feed actively on various crustaceans and 

 larval fish (Dell, 1963). The probable summer 

 migration of the .l-age immature fish is sum- 

 marized in figure IIB. 



The fact that the .l-age fish migrate past a given 

 point for a long period indicates that they must 

 be spread over a large area at sea. Such an ex- 

 tended dLstribution is probalily characteristic of 

 salmon in genera] even in their first summer, as 

 evidenced by the long baud of .0-age salmon of all 

 species along the coast of the Gulf of Alaska 

 described earlier. It is important to emphasize 

 liere that the .l-age immature sfx-keye salmon at 

 this .stage are thoroughly mixed witii the .2-agc 

 immature fi.sh that left Bristol Bay a year earlier; 

 apparently they overtake the previous year's 

 smolts and then follow a similar migratorv i)ath. 



452 



Figure l.S. — Catiches of .2-age and older sockeye salmon 

 during winter gill netting in 19G2 and lOdR (source: 

 French and Mason, 1064 ) . 



The winter data (figs. 10 and 13) indicate that the 

 intermingling of the age groups takes place as 

 early as January. In general, however, the .l-age 

 group in figure 10 was farther south than the older 

 fish shown in figure 13. Thus, it would appear thiit 

 the migration of this age group is independent of 

 the older fish at this early stage. 



The migrations during the autumn and winter 

 of the second year at sea can be inferred from the 

 limited winter sampling and from the distribution 

 and migrations observed in the following s])ring 

 and summer (fig. llC). During fiiis period the .1- 

 age fish add another winter mark on their scales 

 and l)ecome .^-age fish. Some will nniture in this 

 year and migrate homeward to spawn, but others 

 will remain at sea to mature a year later at .3-age. 

 As illustrated in figure 13, .2-age sockeye salmon 

 are distributed widely during the winter (Janu- 

 ary-.Mai-rh) in the central and western JJering Sea 

 and in the Xortli Pacific at most sampling stations 

 north of lat. 45° N. As at other times of the year, 

 Bristol Jiay fish may be expected to be present in 

 most of the sample.s. The data then sutler a ga]) 

 until till' following May, when samples taken by 

 ])urse seines indicate few. if any, sockeye salmon 

 in tjie Alaskan Stream south of the Aleutians. In 

 late May and early June, however, the maturing 

 .2-age sockeye .salmon begin to ai)pear in the 

 catclies ahmg the entire south side of the Aleutians, 

 and they are again migrating westward in the 

 Alaskan Stream. The evideiue. thus, indicates a 

 southward .shift (hiring late winter and early 



U.S. FISH AND WILDLIFE SERVICE 



