Factors influencing habitat use by juvenile interior Fraser coho.

Temperature preference, aerobic scope and upper thermal tolerance in sympatric juvenile chinook slamon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch)

“…Warren (2009) found that coho salmon in this area used smaller tributaries to rear, and those which were not necessarily their natal streams. In fact, coho salmon were found to emigrate out of McKinley Creek where they were spawned and into smaller, cooler tributaries prior to peak summer temperatures (Warren 2009). Although my catch effort was not equal among locations or seasons, I successfully caught fishes in the three tributaries that remained the coolest in summer, which appears to corroborate previous findings by Warren (2009).…”

“…Stream temperature data and results from laboratory experiments in the current studies can build upon previous research done in the watershed with these populations of fishes to help inform specific management decisions for Horsefly River Chinook salmon and coho salmon. In this watershed, both species are known to be highly mobile, moving into several different rearing habitats during the freshwater life stage (Shrimpton et al 2014;Warren 2009). Warren (2009) found that coho salmon in this area used smaller tributaries to rear, and those which were not necessarily their natal streams.…”

“…In this watershed, both species are known to be highly mobile, moving into several different rearing habitats during the freshwater life stage (Shrimpton et al 2014;Warren 2009). Warren (2009) found that coho salmon in this area used smaller tributaries to rear, and those which were not necessarily their natal streams. In fact, coho salmon were found to emigrate out of McKinley Creek where they were spawned and into smaller, cooler tributaries prior to peak summer temperatures (Warren 2009).…”

“…Interior Fraser coho salmon emerge as fry in the spring and migrate into tributaries where they rear for approximately one year before migrating to the ocean as smolts (Sandercock 1991;DFO 2002;Irvine 2002;Hillaby 2011). In the Horsefly River watershed, coho salmon juveniles rear predominantly in narrow streams, with low water velocity and ample cover (Warren 2009). As adults, Horsefly River coho salmon enter the lower Fraser River in October and reach spawning grounds in late October to November (Sandercock 1991;DFO 2002;Irvine 2002;McPhail 2007;Hillaby 2011), migrating up river during a period of lower flow and cooler water temperatures compared to summer conditions (Sandercock 1991).…”

“…Although timing of adult migration differs between the two species, Chinook salmon and coho salmon rear as juveniles in the same tributaries within the Horsefly River watershed and are consequently subject to comparable selective pressures at this life stage (Warren 2009). The difference in adult migration timing between the two species may result in differences in selective pressures for physiological performance across a range of temperatures.…”