Spring Brings Return of Alewives
(Published by The Quoddy Tides, April 27, 2001)
Innovative efforts on the part of Cobscook Bay residents to restore local fisheries are becoming more commonplace. At the heart of one such effort is the return of alewives to their spawning grounds in the Pennamaquan River, Little River, and Boyden Stream. This once abundant fish is increasingly being recognized for the key role it plays in the ecology of the bay.
Alewives are one of the more important foraging fish, feeding on microscopic organisms, phytoplankton and zooplankton, that float in the water. They serve as an important food for cod, haddock and other groundfish, as well as local populations of eagles and osprey. When abundant, the presence of alewives may attract predators away from young salmon and other gamefish. Since the early 1800's, alewives have been commercially harvested as a food fish and, more commonly, for lobster bait.
Their natural history makes alewives particularly vulnerable to changes in the habitat they use. From early May to June, alewives return from the ocean to spawn in streams, lakes, and areas of still water in rivers. Females release from 60,000 to 100,000 or more yellow-orange eggs, which then settle and stick to bottom materials for a short time before hatching. Adults return to sea soon after spawning, most by mid-July.
By late summer or early fall, young alewives begin their migration out to sea. They spend roughly four to five years in the ocean before returning as adults to spawn in the river where they hatched. Anywhere from 40-60% of adult spawning alewives may die. Those that survive may return to spawn for the next two to three years.
Statewide, alewife numbers have declined substantially over the past twenty-five years. In 1976, the peak commercial harvest of alewives reached over 4 million pounds. By 2000, only about 600,000 pounds were harvested. Damming of streams and rivers are blamed for much of this decline, but other factors come into play as well.
Tom Squiers, of the Department of Marine Resources, comments "We've seen a fairly dramatic decline in alewives statewide since the 1970's and 80's. For example, on the St. Croix, the numbers have declined from 6 million to less than 10,000 returning last year. The closing of fishways have certainly played a role in this."
He adds, "A lot of the decline may be due to marine survival, but we don't know yet what is happening out there. Increases in striped bass and cormorant populations, as well as other predators, may be a factor. An increase in the beaver population has also led to more damming of streams."
In some areas, the state has temporarily breached beaver dams in order to allow passage of alewives as they come in to spawn and when they return to sea.
Movements at sea are poorly known. Alewives will congregate in large schools, often mixing with Atlantic herring and menhaden. Some young alewives may remain inshore for one to two years, while older fish have been found in deeper waters offshore in Georges Bank and the upper Bay of Fundy.
Once very abundant in Cobscook's productive waters, alewives here faced obstacles with the damming of the Pennamaquan River and Little River. Man-made channels called fishways contain wooden baffles, which are used to regulate the water depth, and allow fish passage through the dams. However, fishways at these locations had not been maintained over the years, and Cobscook area residents brought this to the attention of the state. Fred Gralenski, of Pembroke, observed the deterioration of the fishways on the Pennamaquan.
"In the late 1950's the fishways were fixed up on the Pennamaquan. Following that, we had big runs on the river into the 70's. Then the fishways were neglected, and the numbers of alewives went way down," comments Gralenski.
Steve Ftorek, of Robbinston, and others were raising concerns about the status of alewife runs on the Little River and Boyden Stream at about the same time. The fishway, built in 1972, had not been repaired when the Little River dam was rebuilt. Area residents had taken to gathering alewives in buckets downstream of the dam, and releasing them upstream so they could spawn.
"Members of the Boyden Lake Association dipped alewives from the stream and over the dam for two or three years, and before that other groups helped move them," says Ftorek.
With the Cobscook Bay Resource Center facilitating conversations between the state and local residents, efforts to replace the fishway baffles were underway in the spring of 2000.
"There's been concern for a long while, but with the help of the Resource Center we received permission to get these fishways repaired," says Gralenski.
With DMR supplying the baffles, Gralenski and his troop of Boy Scouts replaced the damaged baffles on the Pennamaquan with new ones last spring.
On the Little River dam, the crew of the Passamaquoddy Water District helped residents install eighty baffles to allow for passage by spawning alewives.
"The fish fight like hell to get up that stream, and they've been coming up that way for a long time," says Ftorek. "Last summer we had all kinds of young alewives in the lake. Better control of the water levels in Boyden Lake would also be of help."
And, the work for Gralenski's scouting troop is not finished yet.
"We plan to clean up the area near the fishway behind the Crossroads Restaurant, make it into a family park area where people can picnic and learn about the alewife runs at the same time," Gralenski says. "Information on the migrations and the restoration project will be posted in a kiosk built by local students."
Historic runs of spawning alewives in Cobscook Bay are one step closer to being restored. However, more research on the ecological role of alewives in the bay and their decline is needed. The efforts on the Pennamaquan River and Little River to restore the fishways is a prime example of how local initiatives and cooperation can help keep the many interdependent parts of Cobscook's natural system intact.
This column was prepared by Cheryl Daigle and Jim Dow. Cobscook Soundings was a monthly column produced by the Maine Chapter of The
Nature Conservancy. Its purpose was to share what is known about the workings of the
Cobscook Bay marine environment, so that all who make decisions about the use
or care of the bay have the best available information.
Return to Cobscook Bay Resource Center homepage.