Assessing Spatiotemporal Patterns in Fish Assemblages from Acid-Sensitive Streams in the Adirondack and Catskill Mountains Active

 

 

With few exceptions, the contemporary and past effects of acidification on fish populations and communities in streams across acid-sensitive regions of NY have not been documented. The pervasive lack of information only permits anecdotal insight into the spatial effects of acidification on stream-fish assemblages and essentially precludes any broad effort to quantify temporal trends and potential recovery of fish assemblages in less acidic or less toxic streams. Though the effects of acidification on fish assemblages have been qualified in several streams of the eastern Adirondacks during 1979, the 1980s, and early 2000s,  (Schofield and Driscoll 1987; Simonin et al. 2005) quantitative impacts were only assessed at four headwater sites (Baker et al. 1996; Simonin et al. 1993; Wigington et al. 1996) during the late 1980s. These studies were restricted to headwater streams in the Moose River Drainage. Potential impacts on fish assemblages of the region were also inferred from past and present measures of brook trout survival (Baldigo et al. 2007). Comparable investigations were completed in one Catskill Mt. system – the Neversink River (Baker et al. 1996; Baldigo 2000; Baldigo and Lawrence 2000; Baldigo and Murdoch 1997; Van Sickle et al. 1996). Accordingly, little quantitative stream-fish data are available to: (a) define the normal range (and variability) in metrics that characterize stream-fish assemblages, (b) quantify the present-day effects of acidification on stream-fish assemblages, (c) define the relations between pH, ANC, base-cation surplus (BSC), DOC, and inorganic Al ( A _lim )  levels and the condition of stream-fish assemblages, (d) accurately predict the effects that reduced acid deposition may have on stream-fish assemblages, and (e) diagnose or gauge potential recovery (temporal changes) in stream-fish assemblages in the Adirondack and Catskill Mountain Regions. The lack of fishery data is especially problematic because recent increasing trends in DOC concentration  may be changing the underlying relationship between acidity and Alim in surface waters, which could substantially alter the toxicity of acidic waters, and affect the survival and distribution of many acid-sensitive aquatic species.

 

 

 

 

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