Natural Reproduction of Coho Salmon and Chinook Salmon in Some Michigan Streams

Abstract

Abstract Sixty streams in lower Michigan were surveyed for natural reproduction of chinook salmon (Oncorhynchus tshawytscha) and coho salmon (Oncorhynchus kisutch) in 1976-1979. Most chinook reproduction was found in the larger trout streams. Coho salmon also reproduced in the larger trout waters but utilized more of the small tributary streams than did chinook salmon. A positive correlation was found between stream velocity and the amount of chinook salmon reproduction, with no reproduction found in stream areas where the water velocity was below 0.3 m/sec. The increased abundance of chinook salmon fry with increasing velocity may reflect better conditions for reproduction as gravels become coarser. An estimated 630,000 chinook salmon smolts were produced in Michigan's Lower Peninsula tributaries of Lake Michigan in 1979. This was 23% of the chinook smolt production in 1979 from Michigan waters (including hatchery plants). Where substantial reproduction or potential for reproduction is found in Great Lak...