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Brook Trout

Salvelinus fontinalis

Rev. 1.5 - 8/2007

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Species Summary

The native range of brook trout (Salvelinus fontinalis) covers much of North America, from the headwaters of the Chattahoochee River in northern Georgia well into the northeastern provinces of Canada. Its vast historic range includes cold water streams, rivers, lakes, ponds and estuaries. In the United States brook trout have largely been replaced by non-native brown trout and rainbow trout, particularly throughout the southern Appalachians. Widespread introductions of brook trout throughout the American West pose threats to rare native cutthroat trout and bull trout.

A recent assessment by the Eastern Brook Trout Joint Venture examined conditions from Ohio to Maine to Georgia and determined that brook trout populations in streams and rivers remain undisturbed in less than 5% of their historic subwatersheds. Brook trout are extirpated from 21% of subwatersheds. Population data are needed for 32% of subwatersheds across the range, particularly in New York, Pennsylvania and New England. Like other salmonids in the char genus, brook trout are intolerant of water pollution and non-native fish, and are classic indicators of water quality and ecosystem integrity.

Key CSI Findings

  • 62% of subwatersheds in the historic range are currently occupied (3,282 out of 5,278)
  • 1.5% of subwatersheds with brook trout had a Total CSI score > 75 (out of a possible 90)
  • Median Range-wide Condition score = 15/25 for extant populations only (range 9-24)
  • Median Population Integrity score = 7/15 for extant populations only (range 6-15)
  • Median Habitat Integrity score = 13/25 (range 5-24)
  • Median Future Security score: 18/24 (range 10-24)
  • 8% of subwatersheds priority for protection
  • 12% of subwatersheds high priority for reintroduction
  • 62% of subwatersheds priority for restoration
Historic Range Relief Map

Brook Trout Historic Range
Brook Trout Photo

Compared to other trout, the Eastern Brook Trout received relatively low CSI scores for range-wide condition, habitat integrity and especially population integrity. Aside from Maine and a few river systems in upstate New York and northern New England, brook trout populations are highly fragmented and relegated to headwater streams. Brook trout habitat across the Eastern range is highly fragmented. While large blocks of public land do protect habitat, median land stewardship score across the range is only 1.7. A dense road network on private and public land and an abundance of dams have isolated populations, reducing the median connectivity score to 1.2. Lake and pond populations remain intact in 14% of historic subwatersheds. Almost all of these populations are located in Maine, and are mostly impacted by non-native fish, specifically bass and sunfish species.

Virginia contains a concentration of protection priorities at existing population strongholds, particularly in portions of the headwaters of the Potomac, Rappahannock and James Rivers. In much of Cherokee, Pisgah and Nantahela National Forests and Great Smoky National Park, brook trout have been eliminated by a combination of past land use and exotic species establishment. In the Shenandoah Valley region, brook trout have been lost through centuries of poor land use and water quality impacts. Reconnection of isolated populations and reintroduction are priorities where water quality and habitat on private land can be restored.

West Virginia, Maryland and Pennsylvania have large opportunities for restoring subwatersheds impacted by abandoned mine drainage, acid deposition and outdated agricultural and grazing practices. Population strongholds are located in western Maryland and the headwaters of the West Branch Susquehanna. A large percentage of the historical range in this region is prioritized for restoration. Potentially, brook trout may be reintroduced in valley regions impacted by human land use and mitigated abandoned mineland habitats.

Brook Trout Photo

Road culverts, aging dams and non-native species fragment brook trout habitat across much of southern New York, New Jersey, Connecticut and Massachusetts. Expansion of habitat through habitat restoration, improved dam operations, and reconnection of fragmented populations constitute restoration activities in priority areas. Protection and restoration of the relatively rare brook trout strongholds are prioritized for tributary systems to the Delaware River in New Jersey and Pennsylvania, the Catskills in New York, and the Batten Kill watershed in Vermont/New York.

Nearly all of the range’s highest scoring subwatersheds (Total CSI scores > 70) are in Maine, northern New Hampshire and Vermont and New York’s Adirondacks. Those areas with high Future Security scores represent multiple protection priorities across this region, particularly against the introduction of non-native fish. Numerous protection opportunities exist in the portions of the Grass, Hudson, Upper Connecticut and Upper Androscoggin rivers and throughout western and northern Maine.

Prepared by Nathaniel Gillespie, TU, 8/15/07

Total CSI Map

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Brook Trout Total CSI Thumb
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