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Spatial and Temporal Dynamics in Brook Trout Density: Implications for Population Monitoring
Author(s) -
Wagner Tyler,
Deweber Jefferson T.,
Detar Jason,
Kristine David,
Sweka John A.
Publication year - 2014
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 - 10.1080/02755947.2013.847878
Subject(s) - fontinalis , salvelinus , trout , environmental science , sampling (signal processing) , streams , spatial variability , electrofishing , spatial ecology , fishery , physical geography , ecology , abundance (ecology) , statistics , fish <actinopterygii> , geography , biology , mathematics , computer science , computer vision , computer network , filter (signal processing)
Many potential stressors to aquatic environments operate over large spatial scales, prompting the need to assess and monitor both site‐specific and regional dynamics of fish populations. We used hierarchical Bayesian models to evaluate the spatial and temporal variability in density and capture probability of age‐1 and older Brook Trout Salvelinus fontinalis from three‐pass removal data collected at 291 sites over a 37‐year time period (1975–2011) in Pennsylvania streams. There was high between‐year variability in density, with annual posterior means ranging from 2.1 to 10.2 fish/100 m 2 ; however, there was no significant long‐term linear trend. Brook Trout density was positively correlated with elevation and negatively correlated with percent developed land use in the network catchment. Probability of capture did not vary substantially across sites or years but was negatively correlated with mean stream width. Because of the low spatiotemporal variation in capture probability and a strong correlation between first‐pass CPUE (catch/min) and three‐pass removal density estimates, the use of an abundance index based on first‐pass CPUE could represent a cost‐effective alternative to conducting multiple‐pass removal sampling for some Brook Trout monitoring and assessment objectives. Single‐pass indices may be particularly relevant for monitoring objectives that do not require precise site‐specific estimates, such as regional monitoring programs that are designed to detect long‐term linear trends in density. Received April 22, 2013; accepted September 18, 2013