Seasonal Movements and Habitat Use of Brook Trout in the Magalloway River

Fishery Final Report Series No. 08-01

By David P. Boucher

Maine Department of Inland Fisheries and Wildlife
Fisheries and Hatcheries Division
Augusta, Maine

January 2008

Final Report No. 1 (2005-2006)


Brook trout are native to waters of the Upper Androscoggin River drainage in western Maine, where they are highly valued for their ecological, cultural, and recreational attributes. The species is sensitive to impacts associated with human activities such as logging, dams, and urban or agricultural development. Brook trout are especially sensitive to competition from other fish species, and they are easily over-exploited by sport anglers because even novices readily catch them.

Brook trout have become the focus of intense investigation in western Maine in response to the recent establishment of smallmouth bass through an unauthorized introduction. Smallmouth bass are severe competitors with brook trout and they can reduce brook trout production in waters where the two species co-occur. The principal goal of this study was to provide information to guide management and maximize the protection of wild brook trout in the Magalloway River in Oxford County. We used radio telemetry techniques to define seasonal movements of brook trout within the Magalloway River and connecting waters in Maine and New Hampshire. Specific objectives were to describe the timing of movements, and to determine the locations of key seasonal habitats, such as summer foraging, temperature refuges, prespawning and spawning, and overwintering areas.

The Magalloway River is a major tributary to the upper Androscoggin River, originating near the Canadian border in western Maine and eastern New Hampshire. Aziscohos Dam, located 17.7 miles above its confluence with Umbagog Lake and the Androscoggin River, impounds a portion of the river. This study was conducted in this lowest reach below Aziscohos Dam.

Twenty-three brook trout from the Magalloway River were radio-tagged in June 2005 and tracked until mid-July 2006 by foot, small watercraft, aircraft, and snowmobile. Tagged brook trout moved only short distances, or not at all, from their tagging locations during the July-August 2005 period. By mid to late October, the height of the spawning period for most Maine brook trout populations, five tagged trout moved a short distance downstream to the confluence of Abbott Brook, or ascended the brook a short distance. Several other tagged fish took positions either near the mouth of Clark Brook, located a short distance below the lowermost tag site, or in discrete areas about one mile below Abbott Brook. Most movements of brook trout during the autumn period were in a downstream direction.

Post-spawning dispersal occurred rapidly and generally in a downstream direction. Tagged trout overwintered in upstream areas of the Magalloway River in deep, slow moving reaches, in the lower Magalloway River, in the Androscoggin River above Errol Dam, or in Umbagog Lake. Movement of trout from overwintering areas toward summer habitat occurred principally from late March to late April, invariably in an upstream direction. By late May 2006, the remaining tagged fish took positions in close proximity to locations from which they were originally captured and tagged during the previous June. Two tagged fish traveled upstream 24.6 and 25.1 miles to reach summer range in an approximate 30-day period.

Brook trout traveled least during the summer period (average of 0.30 miles), then generally moved short distances (average of 0.72 miles) to spawning areas. Greatest movements occurred in the fall to reach overwintering habitat (average of 6.5 miles) and in the spring (average of 11.7 miles) as they returned to their summer range. The greatest distances traveled by individual trout during the entire study period (late June 2005 to mid July 2006) ranged from 35 to 72 miles.

There were no recorded movements of Magalloway River fish into either the Dead Diamond or Rapid Rivers, and neither adult nor juvenile trout from the Rapid River migrated to the Magalloway or Dead Diamond Rivers. Two tagged brook trout from the Dead Diamond River moved to the upper Magalloway River during the 2005 summer period, presumably to seek temperature refuge. This behavior was less apparent in 2006, probably because temperatures and flows in the Dead Diamond were more suitable than in 2005. These same trout remained in the Magalloway River during the 2005 and 2006 fall seasons, but it could not be determined if they spawned in the same locations as the Magalloway fish. Tagged brook trout from all three rivers overwintered in the north basin of Umbagog Lake.

This study provided information on seasonal habitat use, and identified critical habitat features that support Magalloway River wild brook trout. Our telemetry data and similar work conducted on the nearby Rapid and Dead Diamond Rivers clearly indicate the importance of Umbagog Lake to brook trout in the upper Androscoggin River drainage. These studies also confirmed the need to maintain free passage of brook trout throughout this subdrainage, because fish from all three populations travel long distances to reach habitat critical to their life history.

For more information, please contact:

Dave Boucher, Assistant Regional Fishery Biologist
689 Farmington Road
Strong, Maine 04983-9419
Telephone: (207) 778-3322 Ext. 23