Broad-scale patterns of Brook Trout responses to introduced Brown Trout in New York

North American Journal of Fisheries Management
By: , and 

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Abstract

Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta are valuable sport fish that coexist in many parts of the world due to stocking introductions. Causes for the decline of Brook Trout within their native range are not clear but include competition with Brown Trout, habitat alteration, and repetitive stocking practices. New York State contains a large portion of the Brook Trout's native range, where both species are maintained by stocking and other management actions. We used artificial neural network models, regression, principal components analysis, and simulation to evaluate the effects of Brown Trout, environmental conditions, and stocking on the distribution of Brook Trout in the center of their native range. We found evidence for the decline of Brook Trout in the presence of Brown Trout across many watersheds; 22% of sampled reaches where both species were expected to occur contained only Brown Trout. However, a model of the direct relationship between Brook Trout and Brown Trout abundance explained less than 1% of data variation. Ordination showed extensive overlap of Brook Trout and Brown Trout habitat conditions, with only small components of the hypervolume (multidimensional space) being distinctive. Subsequent analysis indicated higher abundances of Brook Trout in highly forested areas, while Brown Trout were more abundant in areas with relatively high proportions of agriculture. Simulation results indicated that direct interactions and habitat conditions were relatively minor factors compared with the effects of repeated stocking of Brown Trout into Brook Trout habitat. Intensive annual stocking of Brown Trout could eliminate resident Brook Trout in less than a decade. Ecological differences, harvest behavior, and other habitat changes can exacerbate Brook Trout losses. Custom stocking scenarios with Brown Trout introductions at relatively low proportions of resident Brook Trout populations may be able to sustain healthy populations of both species within their present range.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Broad-scale patterns of Brook Trout responses to introduced Brown Trout in New York
Series title North American Journal of Fisheries Management
DOI 10.1080/02755947.2013.830998
Volume 33
Issue 6
Year Published 2013
Language English
Publisher American Fisheries Society
Publisher location Lawrence, KS
Contributing office(s) Great Lakes Science Center
Description 15 p.
First page 1221
Last page 1235
Country United States
State New York
Online Only (Y/N) N
Additional Online Files (Y/N) N