Armstrong, Robert H. April 1971. Age, food, and migration of sea-run cutthroat trout, 


Salmo clarki, at Eva Lake, Southeastern Alaska.  Trans. Am. Fish. Soc. Vol. 100, No. 2.


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Migrations of 1,210 to 1594 out-migrants and 1,203 to 1,682 


in-migrants were recorded at a weir across the outlet of Eva Lake from 1962 through 1964.  


Peak out-migrant movement is mid-May (3 degree C. water temp.) and mid-Sept. to early 


October for in-migrants.  No ct movement in or out from Dec. through Feb. Most migration 


during darkness.


Ages of out-migrants ranged from 3 to 10 yr olds with the majority being 5,6, and 7.  Smolts 


were 2 (3%), 3 (80%), and 4 (17%).  Diet during summer were primarily young salmon 


(pink and chum fry) and insects and during the winter the diet was insects and stickelbacks in 


the lake. Fish fed primarily on insects during their out-migration and amphipods and young 


salmon in salt water.  Fed on coho and sockeye fry in the lake, 36% of ct had young salmon 


in their stomachs.  Out-migrant length (fork length) ranged from 125 mm to 390 mm. with the 


mean of 284 mm.


The only other sea-run ct study with enough information to compare to the Eva Lake study 


was conducted by Sumner in 1962 at Sand Creek in Oregon.  The Sand Creek ct out 


migration was about 1 month earlier than at Eva Lake and the in-migration about 1 month 


later than at Eva Lake. The age at smolt migration was similar for each location (3 yrs old).


The study suggested Eva Lake ct returned from the ocean to over winter in the lake each 


year.  In Oregon ct are known to over winter in coastal estuaries.