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Snorkeling as an alternative to depletion electrofishing for assessing cutthroat trout and brown trout in stream pools

January 1, 2003

We compared abundance and length structure estimates of cutthroat trout (Oncorhynchus clarki) and brown trout (Salmo trutta) of 15 cm total length or greater obtained by snorkeling in stream pools with estimates obtained by depletion electrofishing. We sampled 12 pools in each of two streams formed by large springs in the Salt River Valley of western Wyoming. Snorkeling counts provided a relatively accurate index of depletion electrofishing estimates of abundance of cutthroat trout, but not brown trout. Linear regression analysis showed that snorkeling counts were significantly related to depletion electrofishing estimates for both cutthroat trout (P < 0.001) and brown trout (P = 0.002), but the coefficient of determination for brown trout (r2 = 0.33) was low compared to cutthroat trout (r2 = 0.95). Frequencies of fish in three length classes observed by snorkeling and depletion electrofishing were close to being significantly different for cutthroat trout (P = 0.066) and substantially different for brown trout (P= 0.005). Snorkeling frequently failed to observe fish in the shortest length class (15–29 cm total length) of both cutthroat trout and brown trout. 

Publication Year 2003
Title Snorkeling as an alternative to depletion electrofishing for assessing cutthroat trout and brown trout in stream pools
DOI 10.1080/02705060.2003.9664487
Authors M. P. Joyce, W.A. Hubert
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Freshwater Ecology
Index ID 70025401
Record Source USGS Publications Warehouse