Premium
Length Variation in Age‐0 Westslope Cutthroat Trout at Multiple Spatial Scales
Author(s) -
McGrath Kathleen E.,
Scott J. Michael,
Rieman Bruce E.
Publication year - 2008
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/m07-120.1
Subject(s) - trout , spatial variability , range (aeronautics) , biology , elevation (ballistics) , ecology , streams , interquartile range , fish <actinopterygii> , environmental science , fishery , statistics , mathematics , geometry , computer network , materials science , computer science , composite material
Abstract Phenotypic diversity provides ecological and evolutionary functions, stabilizing populations in variable environments. Although benefits of larger body size in juvenile fishes are well documented, size variation may have value as well. We explored the distribution of length and length variation in age‐0 westslope cutthroat trout Oncorhynchus clarkii lewisi at three spatial scales: area (10 2 km 2 ), stream (10 1 km 2 ), and site (10 0 km 2 ). In addition, we examined relationships between length variables (mean length and interquartile range of length) and instream (temperature and conductivity) and landscape (aspect, elevation, headwater distance, and valley width) variables that were expected to be associated with fish size. Conductivity was included as a surrogate for productivity. Most variation in mean length and interquartile range of fish length was found among areas (62.2% and 62.6%, respectively). Mean length also varied among streams and sites (21.9% and 15.8%, respectively). Similarly, interquartile range of fish length varied among streams and sites (19.1% and 18.3%, respectively). Both length variables were associated with temperature and elevation. Mean fish length was also associated with conductivity, but the association between interquartile length range and conductivity was weak. We conclude that the conservation of variation in phenotypic attributes, such as length, in westslope cutthroat trout may require conservation of viable populations across broad areas and across environmental gradients that are associated with growth.