Premium
Persistent Mortality of Brook Trout in Episodically Acidified Streams of the Southwestern Adirondack Mountains, New York
Author(s) -
Baldigo Barry P.,
Lawrence Gregory,
Simonin Howard
Publication year - 2007
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/t06-043.1
Subject(s) - salvelinus , trout , fontinalis , streams , snowmelt , water quality , mortality rate , environmental science , watershed , ecology , zoology , hydrology (agriculture) , biology , fish <actinopterygii> , fishery , demography , geology , surface runoff , computer network , computer science , geotechnical engineering , machine learning , sociology
Water chemistry, discharge, and mortality of caged brook trout Salvelinus fontinalis were characterized in six headwater streams in the southwestern Adirondack Mountains of New York during spring 2001–2003. Results were compared with mortality recorded during similar tests during 1984–1985, 1988–1990, and 1997 to assess contemporary relations between stream acidification and brook trout mortality, the effects of exposure duration on mortality, and the effects of decreased rates of acidic deposition on water quality and fish mortality. Water quality and mortality of caged, young‐of‐the‐year brook trout were evaluated during 30‐d exposure periods from mid‐April to late May during the most recent tests. In 2001–2003, mortality ranged from 0% to 100% and varied among streams and years, depending on the timing of toxicity tests in relation to the annual snowmelt and on the ability of each watershed to neutralize acids and prevent acutely toxic concentrations of inorganic monomeric aluminum (Al im ) during high‐flow events. Mortality rates in 2001–2003 tests were highly variable but similar to those observed during earlier tests. This similarity suggests that stream water quality in the southwestern Adirondack Mountains has not changed appreciably over the past 20 years. Concentrations of Al im greater than 2.0 and 4.0 μmol/L were closely correlated with low and high mortality rates, respectively, and accounted for 83% of the variation in mortality. Two to four days of exposure to Al im concentrations greater than 4.0 μmol/L resulted in 50–100% mortality. The extended periods (as long as 6 months) during which Al im concentrations exceeded 2.0 and 4.0 μmol/L in one or more streams, combined with the low tolerance of many other fish species to acid and elevated Al im concentrations, indicate a high potential for damage to fish communities in these and other poorly buffered streams of the Northeast.