Study Finds Sea-run Alewives No Threat to Bass

By Diana Graettinger

Thursday, August 31, 2006 – Bangor Daily News

CALAIS – A multiagency study concludes that sea-run alewives don’t appear to be a threat to the smallmouth bass, a popular sport fish, in seven Down East lakes.

The study involved lakes that reach from Grand Lake Stream to East Machias. They are Grand Falls and Woodland flowages and Big, Meddybemps, Gardner, Cathance and Pocumcus lakes.

Bill MacDonald, executive director of Maine Rivers of Hallowell, along with some research specialists, were in Washington County on Tuesday night to review their findings at Washington County Community College.
The $140,000 study was conducted in the past two years. It is based on information from as far back as the 1980s.
The agencies that picked up the tab for the study were: the Gulf of Maine Council’s Habitat Program, the U.S. Fish and Wildlife Service, the International Joint Commission, the New Brunswick Wildlife Trust Fund, the U.S. Environmental Protection Agency, the Maine Outdoor Heritage Fund and the National Fish and Wildlife Foundation.

Among the findings:
. There is no evidence from historical data that the anadromous alewife has systematically harmed smallmouth bass in terms of size and condition.
. The data suggest that the bass actually grew faster in the presence of anadromous alewife.
. Studies of diets showed that the alewife diet is different from that of the bass.
. Fishing tournament returns revealed there is no difference between the weights of the fish from lakes that had alewives and those that didn’t.
. The distinct genetic profiles from the various watersheds suggest that the alewives return specifically to the streams where they were born.

Curtis Bohlen, a board member for Maine Rivers and coordinator of the project, said the historical data suggest that there is “no obvious smoking gun” indicating that alewives are causing problems for smallmouth bass either in terms of growth or size.

The study noted that the alewives enter the river in the springtime at the same time the salmon are leaving.
“If you don’t have the alewives coming in at the same time that the salmon smolts are exiting, then the salmon smolts are much more susceptible to prey from osprey, eagles, cormorants and seals. So the alewives can actually provide cover to the salmon smolts,” MacDonald said.

In addition, the study said, the alewives that may be harming the bass population are homegrown. “It is very clear from the genetics work that the landlocked alewife in the watershed are not native to the watershed,” Bohlen said. “They didn’t evolve locally. They are an introduced population and we have not done the work to find out who introduced them and when and why. And there’s a real potential, based on work that’s been done elsewhere, that those landlocked alewives are a potentially and fairly significant threat to fisheries in the St. Croix watershed because similar landlocked population have caused problems elsewhere.”

The battle over the migration patterns of the alewife has gone on for years and has involved people from both sides of the border.

Alewife runs in the St. Croix watershed, a boundary between the United States and Canada, have been limited since 1995 when the Maine Legislature authorized barriers at the dams at Grand Falls and Baileyville to keep fish from moving up the waterway.

The fish, which resemble herring, are used in commercial fishing and provide food for bald eagles, osprey and various freshwater sport fish. At one time the river supported large runs of anadromous species, including Atlantic salmon, shad and alewives

In 1995, Maine Guides, frustrated by the decline of smallmouth bass, asked the Legislature for a law that would permanently close the state fishways to sea-run alewife. The idea was to keep adult alewives from spawning in the center and upper areas of the system. The dams are now managed by the Montreal-based papermaker Domtar Inc.
New Brunswick Power Corp. owns the Milltown dam, which is below the Baileyville Dam and a few miles north of downtown Calais. The lower St. Croix River between Milltown, a village in Calais, and Baileyville supports a small native population of sea-run alewives. The adult fish enter the river in the spring to lay their eggs in still waters, lakes and flowages. The juvenile fish leave fresh water in late summer to spend two to four years at sea before they return to fresh water to spawn.

Canada objected to Maine’s decision to close the upper dams and expressed concern that the action would limit the alewives’ natural spawning habits. Canadian agencies threatened to catch the alewives downstream and truck them around the closed dams for release upstream, something they have been doing for the past few years.
The study, Bohlen cautioned, is not suggesting that anyone is wrong. “We’ve looked at a small number of lakes and a small number years because that’s where we had historical data and one of the things we’ve clearly seen is conditions vary from year to year and lake to lake,” he said.

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