Androscoggin River Project
The Androscoggin River, an interstate waterway with a drainage area of 3,460 square miles above tidewater, is the third largest river that empties into the coastal waters of Maine. From its headwaters at Lake Umbagog, New Hampshire, the river drops an average of 7.74 feet per mile along its 161-mile long course to tidewater at Brunswick and into Merrymeeting Bay.
Prior to construction of dams in 1807, Atlantic salmon, American shad, river herring (alewives and blueback herring), sturgeon, and American eels were very abundant in the Androscoggin River. One of the earliest river fisheries in New England occurred at Pejepscot Falls in 1628. Construction of dams and severe water pollution virtually eliminated sea-run fish populations from the Androscoggin River by the early 1930s.
Since the early 1970s, water pollution abatement efforts have resulted in the dramatic improvement of water quality in the Androscoggin River. Remnant populations of rainbow smelt, alewives, and American shad have begun to expand in the estuary.
In 1983, the Maine Department of Marine Resources (DMR) initiated an anadromous fish restoration program in the Androscoggin River -- its goal to protect, enhance, and restore native fish communities, and necessary habitat. To date, efforts have focused on restoring American shad and river herring to historic habitat areas. Simultaneously, when Central Maine Power constructed a new hydropower dam at Brunswick, a fishway and trapping facility allowed some migratory fish to move upstream past the dam.
In 1987, upstream and downstream passages were constructed at the second dam on the river (Pejepscot); in 1988, passage provisions were made at the third dam on the river (Worumbo). These three facilities currently allow upriver fish migration as far as Lewiston Falls.
Department personnel operate the Brunswick Fishway/trapping facility. The fishway is 570 feet long and consists of 42 individual pools, with a one-foot drop between each. The trapping facility, located at the upstream end of the fishway, provides biologists the opportunity to collect data on migratory and resident fish species that use the fishway. As fish swim to the top of the fishway, fixed grating guides them past a viewing window and into a 500-gallon capacity fish hoist (trap). The hoist elevates the fish to overhead sorting tanks where fisheries staff sort and pass fish upstream. Species such as Atlantic salmon pass upstream above the 40-foot dam after biological data are collected. Fisheries biologists remove exotic species, such as carp or white catfish, from the sorting tanks and return them to the river below the dam. Each spring, adult river herring and American shad return to the river to reproduce. To assist restoration efforts, fisheries staff captures river herring and American shad and transports them by truck to historic spawning habitats within the watershed.
The goal for the river herring and American shad restoration effort is a surplus of 175,000 and 59,000 pounds, respectively, for harvesting by recreational and commercial fishermen. Since American shad runs remain extremely low in the Androscoggin River, DMR releases a maximum of 1,000 adult shad from the Merrimack River into habitat below Lewiston Falls to aid in restoration. In 2007, 206 adult American shad were released into the Worumbo headpond.
In 2007, six adult shad returning to spawn in the Androscoggin River were captured at the Brunswick Fishway. Between 1999 and 2004, underwater video cameras installed at the fishway showed high numbers of shad moving in and out of the fishway throughout the migratory spawning season. In addition, radio telemetry studies aimed at tracking shad movements in the fishway and adjacent river sections occurred through the 2005 spawning season. An assessment of shad movement in and around the fishway will continue in upcoming years to determine the best method of passing adult shad upstream to their native spawning habitat.
Joint studies, in partnership with Bowdoin College, assessed habitat use of American shad below the Brunswick Dam in 2005 and 2006. Shad eggs were caught by specialized nets in areas of the lower Androscoggin River providing some evidence of natural spawning activity occurring.
A total of 29 different fish species have used the Brunswick Fishway since its opening in 1983. Following is the most recent summary of numbers and species of fish captured at Brunswick:
Fish Species Counted at Brunswick