Restoring Lost Ecological Connections: Fish Ladders and Dam Removal

Growing up in midcoast Maine I was accustomed to celebrating the return of the alewives, an anadromous, or sea-run fish, each spring. Recently a project to restore the fish ladder for the alewives has neared completion in a stream at Damariscotta Mills. The Maine state legislature called for a fish passage in 1741, which led to the town finally building the fish ladder in 1807 to allow the alewives to return to Maine’s streams, ponds and lakes to spawn. The project to rebuild the old fish ladder began 200 years later in 2007 and has entered a final phase in 2012. One challenge for the restoration crew has been to make sure that the fish ladder was functional for the alewives each season. The running of the alewives just occurred in late May/early June.

Meanwhile, another river in Maine supports the run of alewives, salmon, sturgeon and other sea-run fish: the Penobscot, Maine’s largest river. A major component of a restoration project to restore critical habitat in Maine’s largest watershed is underway this week along the Penobscot River. The Great Works Dam on the lower part of the river is being removed this week. See a video of this dam removal (June 11, 2012). This is the culmination of a lot of planning over the past eight years on the part of federal, state and tribal governments, along with nonprofit and for-profit parties.  These have included the State of Maine, The Nature Conservancy, National Oceanic Atmospheric Administration, Penobscot Nation, Maine Audubon, Natural Resources Council of Maine, Trout Unlimited, American Rivers, Atlantic Salmon Federation and other partners. Together they form the Penobscot River Restoration Trust. This project began in 1999, but an essential agreement formed in 2004 laid the groundwork for the collaborative restoration efforts. This unprecedented agreement set out to accomplish these things:

  1. Restore self-sustaining populations of native sea-run fish, such as the endangered Atlantic salmon;
  2. Renew opportunities for the Penobscot Nation to exercise sustenance fishing rights;
  3. Create new opportunities for tourism, businesses and communities;
  4. Resolve long-standing disputes and avoid future uncertainties over the regulation of the river.

The agreement further laid out a plan to remove two dams on the lower part of the river, including the Great Works Dam removed this week, and to construct fish bypasses by a third dam and to improve fish passage at four other dams. In 2007, the Penobscot River Restoration Trust and the U.S. Fish and Wildlife Service announced the project, and added that it would have far-ranging benefits on the Gulf of Maine, protecting endangered species, migratory birds, as well as riverine and estuarine wetlands. It would also enhance recreational activities, such as paddling and fishing and watching wildlife.  The riverine habitat is home to osprey, kingfishers, otters and bald eagles. The project has been widely known as one of the most innovative river restoration projects in the nation.

Some members of the Penobscot River Restoration Trust have made comparisons to the 1999 dam removal on the Kennebec, which was among notable dam removal projects that set a trend throughout the country. The two rivers share some of the same ecological communities. Those involved with monitoring the Kennebec since 1999, have noted a return of more birds, namely osprey and bald eagles, due to the increased number of alewives present, a food source for the birds of prey. “It’s restoring some of the lost ecological connections in the river. First, we’ve seen the rebuilding of the herring run. And now we’ve seen the building of the eagle and osprey populations,” according toAndrew Goode of the Atlantic Salmon Federation.

The Penobscot River and its tributaries flow through the Maine North Woods to Penobscot Bay, in midcoast Maine. Scientists began collecting baseline data for monitoring wetlands, rare plants, invasive species, geomorphology, water quality, smolt telemetry (tagging and monitoring the actively migrating young salmon), tracking fish movements and fish communities, including sturgeon, salmon and other species, in 2009. See monitoring poster. For more information about the monitoring work with sturgeon,click here.

Dam removal, fish passage and river restoration projects are happening in other parts of the country, too. Trout Unlimited has recently blogged about the legacy of “Making rivers whole again” and what’s considered the largest dam removal project in the country is underway in the Olympic wilderness of Washington state. The Elwha Dam removal project began last fall to restore the Elwha River and ecosystem. It’s managed by theNational Park Service. A recent look at case-studies on dam removal and legislation in the U.S. from an energy perspective was provided in “Exploring the Reasons behind Dam Removal.” In addition, the Connecticut River has become the first National Blueway thanks to the efforts of over 40 local, state and federal government agency and nonprofit and for-profit coalition members. The designation will improve recreational opportunities for boating, canoeing, trail-building and conservation along the river in four states: CT, NH, MA and VT. The idea originated out of President Obama’s “America’s Great Outdoors” initiative. For a snapshot of other ideas in the Great Outdoors initiative, click here.

Updated: April 4, 2013: Blocked Migration: Fish Ladders On U.S. Dams Are Not Effective

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