Premium
Modeling Stream Network‐Scale Variation in Coho Salmon Overwinter Survival and Smolt Size
Author(s) -
Ebersole Joseph L.,
Colvin Mike E.,
Wigington Parker J.,
Leibowitz Scott G.,
Baker Joan P.,
Church M. Robbins,
Compton Jana E.,
Miller Bruce A.,
Cairns Michael A.,
Hansen Bruce P.,
La Vigne Henry R.
Publication year - 2009
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/t08-047.1
Subject(s) - oncorhynchus , streams , juvenile , habitat , biology , fishery , range (aeronautics) , ecology , context (archaeology) , structural basin , fish <actinopterygii> , computer network , paleontology , materials science , computer science , composite material
We used multiple regression and hierarchical mixed‐effects models to examine spatial patterns of overwinter survival and size at smolting in juvenile coho salmon Oncorhynchus kisutch in relation to habitat attributes across an extensive stream network in southwestern Oregon over 3 years. Contributing basin area explained the majority of spatial variation ( R 2 = 0.57‐0.63) in coho salmon overwinter survival (range = 0.02‐0.63), with highest survival rates observed in smaller headwater and intermittent streams. Other habitat attributes, including proportional pool area, percent exposed bedrock substrate, percent broadleaf canopy cover, and adult salmon carcass density, were relatively poor predictors of survival. Indices of individual fish condition, including fall parr fork length, condition factor, and parasite infestation rates, were also relatively uninformative in coho salmon overwinter survival models. Coho salmon smolt length was primarily a function of length at the time of fall tagging, but stream type, contributing basin area (positive effect), thermal history (positive effect), and black spot infestation (i.e., trematode metacercariae; negative effect) were also important. The consistent, broad spatial gradients in overwinter survival observed in this study can help guide efforts designed to enhance coho salmon production in coastal streams and suggest that habitat protection, restoration, and enhancement strategies will be best guided by a whole‐basin context.