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Patterns of coho salmon size and survival within a stream network
Citation:
EBERSOLE, J. L., M. Colvin, P. J. WIGINGTON JR, S. G. LEIBOWITZ, K. Burnett, AND J. C. Firman. Patterns of coho salmon size and survival within a stream network. Presented at International Environmetrics Society annual meeting, Corvallis, OR, June 15 - 17, 2009.
Impact/Purpose:
Effective habitat restoration planning requires correctly anticipating demographic responses to altered habitats.
Description:
Effective habitat restoration planning requires correctly anticipating demographic responses to altered habitats. Network-scale investigations of habitat-specific growth and survival of juvenile salmonids have provided critical insights that can now better inform and help prioritize rehabilitation activities. Using habitat-specific growth, survival and movement data from PIT-tagged coho salmon (Oncorhynchus kisutch), we illustrate the potential benefits of spatially-explicit habitat restoration scenarios in an Oregon, USA coastal basin. Use of in-stream antenna arrays, remote scanning of PIT-tagged fish, and multiple recapture efforts allowed us to document seasonal movement, growth and survival throughout a 67 km2 basin over 4 years. We used hierarchical linear models to evaluate network patterns of juvenile coho salmon abundance, size, and survival rates. We found that under present conditions, survival and growth are greater in tributary habitats compared to downstream mainstem habitats. Intermittent tributaries are particularly important as seasonal refuges and provide valuable spawning and foraging habitats. Under potential restoration scenarios, the greatest benefits, in terms of sensitivity of juvenile coho salmon population abundances, are likely to be observed in the mainstem. These findings highlight the value of habitat-specific demographic data to restoration planning, and the usefulness of individual-based approaches for fish population monitoring at whole-basin scales.