Bringing Alewives Back from the Brink

After decades of population declines, alewives are slowly but surely returning to their ancestral habitat on Maine’s St. Croix River – and that’s good news for Maine’s environment, economy, and fisheries.

CLF in Action

Alewives play a critical role in the health of Maine’s fisheries, serving as food for cod, salmon, and striped bass and as a bait fish for lobstermen. In the mid-90s, the alewife population collapsed due to a 1995 state law that blocked the fish from reaching their freshwater spawning grounds.

That’s when CLF took action to save the keystone species. Successful lawsuits against the Environmental Protection Agency and the State of Maine, along with pressure from the Passamoquoddy tribe and other groups, led the State to invalidate the1995 law. In 2013, the St. Croix River was opened to alewives once again – and populations have been slowly on the rise ever since.

CLF is working to ensure that alewives are given a fighting chance to recover not just on the St. Croix but throughout New England. Today, we’re involved with relicensing proceedings for dams further up the St. Croix River and ensuring fish passage on the Presumpscot River that empties into Casco Bay.

What’s at Stake

The alewife, which lives in the ocean but travels up rivers each spring to spawn, is a “keystone species” that provides food for many animals, birds, and larger fish species native to Maine’s marine and fresh waters. In spite of its importance, alewife populations have dipped dangerously low along the East Coast. This stark decline has two main causes: alewives being caught as bycatch when in ocean waters and being blocked from their spawning habitat by dams that prevent them from traveling up rivers.

On Maine’s St. Croix River, for example, a population of more than 2.5 million alewives in the 1980s plummeted to barely 900 in 2002, due to a deliberate decision to keep the fish from reaching spawning grounds upriver. Regionwide, the alewife population has dipped to 10,000 – not nearly enough to sustain the fisheries that depend on them.