A Mid Atlantic brook trout (Salvelinus fontinalis) stream sustainability statistic for rating non-tidal streams

Abstract

Due to the decline of Mid Atlantic brook trout populations coupled with diminishing budgets of relevant natural resource agencies who monitor the populations, a quick and cost effective assessment of brook trout streams or potential brook trout streams in the Mid-Atlantic United States is warranted. Using five core metrics – two watershed metrics (percent land use in agriculture and distance to the nearest road from the survey site) and three in-stream metrics (riffle/run quality, dissolved oxygen content and water temperature), a classification model has been developed, useful as preliminary indication as to a stream’s suitability to sustain brook trout populations. Developed via discriminant analysis using Maryland Department of Natural Resources’ historical stream data, two classification equations (Smith–Sklarew equations) can be simplified into one equation, which produces a sustainability statistic (S). Should the five field measurements from the metrics produce a positive “S” value at a given site, then the stream reach most likely favors conditions suitable for sustainable brook trout populations. Conversely, negative “S” values indicate less than adequate conditions for sustainable brook trout populations.