- Juvenile salmonids display highly variable spatial and temporal patterns of early dispersal
that are influenced by density-dependent
Although juvenile coho salmon (Oncorhynchus kisutch) movement patterns in streams
and their relationship with body mass and growth have been examined in previous
studies, most observations were limited to one season or one stream section. In this
study, we monitored the movement of juvenile coho salmon throughout their period
of residence in a coastal basin to identify prevalent dispersal strategies and their relationships
with body mass, growth rates and survival. Our results revealed seasonally
and spatially variable movement patterns. Juvenile coho salmon that dispersed to tidally
affected reaches soon after emergence remained more mobile and expressed
lower site fidelity than those individuals that remained in upper riverine reaches. We
did not detect significantly different growth rates between sedentary and mobile individuals.
Although a greater proportion of sedentary than mobile fish survived winter
to emigrate from the creek in the spring, reach of residence at the onset of winter influenced
these survival estimates. Hence, apparent summer-to-
survival for mobile
individuals was greater than for sedentary fish in tidally influenced reaches,
whereas in riverine reaches the sedentary strategy seemed to be favoured. Our research
identified complex movement patterns that reflect phenotypic and life history
variation, and underscores the importance of maintaining diverse freshwater and estuarine
habitats that support juvenile coho salmon before marine migration.
- Weybright AD, and Giannico GR. Juvenile coho salmon movement, growth and survival in a coastal basin of southern Oregon. Ecol Freshw Fish. 2018;27:170–183. https://doi.org/10.1111/eff.12334
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