Image
Ecology and Vulnerability
Brook Trout
Photo credit: U.S. Forest Service
Scientific name
Salvelinus fontinalis
Profile: Brook Trout ▾▸
Background
Brook trout are an economically important game species throughout their native range, which extends south in the Appalachians to Georgia1 and north to the Atlantic drainages of...
Background
Brook trout are an economically important game species throughout their native range, which extends south in the Appalachians to Georgia1 and north to the Atlantic drainages of Newfoundland, Labrador, and Quebec2. Brook trout in Massachusetts are found primarily in streams that have cold, highly oxygenated water3. They generally do not tolerate extended periods of water temperatures above 20°C/68°F3, and the ideal temperature for growth and activity is between 12-19°C (53.6-66.2°F)4. Because of their requirements for clean, cold water, brook trout have experienced extensive reductions in distribution and abundance because of habitat degradation1. In Massachusetts, wild, reproducing populations of brook trout have been greatly reduced and the majority that remain are restricted to isolated headwater streams5.
Climate Impacts
This species’ need for cold water implies that there is great potential for climate change to impact brook trout populations. Indeed, modeling studies conducted in various parts of its range, including parts of Canada6 and in the southern Appalachians7, suggest large reductions in future distributions for brook trout. Studies commonly have found that in streams where temperatures exceed 20°C/68°F for extended periods, brook trout are either at low abundance, or are absent altogether8,9,10. Brook trout begin to experience significant mortality as water temperatures approach 25°C/77°F11. However, studies have observed physiological indicators of heat stress in temperatures as low as 21°C/68°F12. These sublethal temperatures are accompanied by decreased feeding, growth, and reproduction13,14. In one Adirondack Lake with marginal temperatures for brook trout, warm temperatures in some years resulted in complete failure to reproduce13.
Some studies have found that different strains of brook trout have different degrees of thermal tolerance, suggesting some limited capacity to adapt to higher temperatures15. Under such conditions, trout seek out thermal refuges such as inflows from cold tributaries or groundwater inputs, where they will aggregate until overall temperatures are more favorable16. However, on a broad geographic scale, distribution is largely defined by temperature constraints16,17, suggesting that adaptive capacity is limited. Additionally, brook trout are able to persist in surprisingly small, isolated populations above barriers in headwater streams18 so there is potential that these trout could continue to remain in isolated pockets in areas where larger populations decline19. While brook trout will likely not disappear from Massachusetts, reductions in suitable habitat are expected.
References
1. Hudy, M., T.M. Thieling, N. Gillespie, and E.P. Smith. 2008. Distribution, status, and land use characteristics of subwatersheds within the native range of brook trout in the eastern United States. North American Journal of Fisheries Management 28:1069-1085.
2. Ficke, A.D., D.P. Peterson, and W.A. Janowsky. 2009. Brook trout (Salvelinus fontinalis): a technical conservation assessment. USDA Forest Service, Rocky Mountain Region. Available: <http://www.fs.fed.us/r2/projects/scp/assessments/brooktrout.pdf>. (Accessed on 20 May 2015).
3. Hartel, K.E., D.B. Halliwell, and A.E. Launer. 2002. Inland Fishes of Massachusetts. Massachusetts Audubon Society, Lincoln, MA.
4. Waco, K.E., and W.W. Taylor. 2010. The influence of groundwater withdrawal and land use changes on brook charr (Salvelinus fontinalis) thermal habitat in two coldwater tributaries in Michigan, U.S.A. Hydrobiologia 650:101-116.
5. Eastern Brook Trout Joint Venture. 2006. Eastern Brook Trout: Status and Threats. Trout Unlimited. Available:< http://easternbrooktrout.org/reports/eastern-brook-trout-status-and-threats/view> (Accessed on 20 May 2015).
6. Chu, C., N.E. Mandrak, and C.K. Minns. 2005. Potential impacts of climate change on the distributions of several common and rare freshwater fishes in Canada. Diversity and Distributions 11:299-310.
7. Flebbe, P.A., L.D. Roghair, and J.L. Bruggink. 2006. Spatial modeling to project southern Appalachian trout distribution in a warmer climate. Transactions of the American Fisheries Society 135:1371-1382.
8. Kratzer, J.F., and D.R. Warren. 2013. Factors limiting brook trout biomass in northeastern Vermont streams. North American Journal of Fisheries Management 33:130-139.
9. Stranko, S.A., R.H. Hilderbrand, R.P. Morgan, M.W. Staley, A.J. Becker, A. Roseberry-Lincoln, E.S. Perry, and P.T. Jacobson. 2008. Brook trout declines with land cover and temperature changes in Maryland. North American Journal of Fisheries Management 28:1223-1232.
10. Wehrly, K.E., M.J. Wiley, and P.W. Seelbach. 2003. Classifying regional variation in thermal regime based on stream fish community patterns. Transactions of the American Fisheries Society 132:18-38.
11. McCormick, J.H., K.E.F. Hokanson, and B.R. Jones. 1972. Effects of temperature on growth and survival of young brook trout, Salvelinus fontinalis. Journal of the Fisheries Research Board of Canada 29:1107-1112.
12. Chadwick, J.G., K.H. Nislow, and S.D. McCormick. 2015. Thermal onset of cellular and endocrine stress responses correspond to ecological limits in brook trout, an iconic cold-water fish. Conservation Physiology 3:1-12.
13. Robinson, J.M., D.C. Josephson, B.C. Weidel, and C.E. Kraft. 2010. Influence of variable interannual summer water temperatures on brook trout growth, consumption, reproduction, and mortality in an unstratified Adirondack lake. Transactions of the American Fisheries Society 139:685-699.
14. Warren, D.R., J.M. Robinson, D.C. Josephson, D.R. Sheldon, and C.E. Kraft. 2012. Elevated summer temperatures delay spawning and reduce redd construction for resident brook trout (Salvelinus fontinalis). Global Change Biology 18:1804-1811.
15. Stitt, B.C., G. Burness, K.A. Burgomaster, S. Currie, J.L. McDermid, and C.C. Wilson. 2014. Intraspecific variation in thermal tolerance and acclimation capacity in brook trout (Salvelinus fontinalis): Physiological implications for climate change. Physiological and Biochemical Zoology 87:15-29.
16. Baird, O.E., and C.C. Krueger. 2003. Behavioral thermoregulation of brook and rainbow trout: Comparison of summer habitat use in an Adirondack river, New York. Transactions of the American Fisheries Society 132:1194-1206.
17. Meisner, J.D. 1990. Effect of climatic warming on the southern margins of the native range of brook trout, Salvelinus fontinalis. Canadian Journal of Fisheries and Aquatic Sciences 47:1065–1070.
18. Letcher, B.H., K.H. Nislow, J.A. Coombs, M.J. O’Donnell, and T.L. Dubreuil. 2007. Population response to habitat fragmentation in a stream-dwelling brook trout population. PloS ONE 2(11):e1139.
19. Kanno, Y., J.C. Vokoun, and B.H. Letcher. 2014. Paired stream-air temperature measurements reveal fine-scale thermal heterogeneity within headwater brook trout stream networks. River Research and Applications 30:745-755.
Climate Change Vulnerability Assessment: Brook Trout (Maine)
Ranking
Moderately Vulnerable
Confidence
Moderate
Climate scenario
Not specified
Location
Maine
Time period
Not specified
Climate Change Vulnerability Assessment: Brook Trout - Sea Run (Maine)
Ranking
Moderately Vulnerable
Confidence
Low
Climate scenario
Not specified
Location
Maine
Time period
Not specified
Climate Change Vulnerability Assessment: Brook Trout (Vermont)
Ranking
Highly Vulnerable
Confidence
High
Climate scenario
Not specified
Location
Vermont
Time period
2050-2100
Climate Change Vulnerability Assessment: Brook Trout (New York)
Ranking
Highly Vulnerable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
New York
Time period
2050
Climate Change Vulnerability Assessment: Brook Trout (Northern Appalacians & Maritime Canada)
Ranking
Presumed Stable
Confidence
Moderate
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
Northern Appalacians & Maritime Canada
Time period
2050
Climate Change Vulnerability Assessment: Brook Trout (North Atlantic Coast)
Ranking
Moderately Vulnerable
Confidence
Moderate
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
North Atlantic Coast
Time period
2050
Climate Change Vulnerability Assessment: Brook Trout (West Virginia)
Ranking
Highly Vulnerable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
West Virginia
Time period
2050
Climate Change Vulnerability Assessment: Brook Trout (Connecticut)
Ranking
Highly Vulnerable
Confidence
Not assessed
Climate scenario
SRES B1/A1B/A2 (Lowest/mid-range/low emissions scenario)
Location
Connecticut
Time period
2080