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Alewives' Effect on Algae Nets Debate Around China Lake

August 13, 2008 - CHINA -- Alewives may be the "magic bullet" that will significantly reduce the annual algae blooms in China Lake.

Or introducing schools of the little migratory fish may damage water quality and sport fishing.

No one will know for a few years -- alewives won't be put into China Lake without doing more research and solving logistical problems.

Nate Gray of the Department of Marine Resources, guest speaker at Thursday's China Lake Association annual meeting, said as the number of alewives in Vassalboro's Webber Pond has increased, water quality has improved.

He explained that zooplankton -- tiny animals in the water -- eat the algae and in turn are eaten by the alewives. The alewives incorporate into their bodies the phosphorus that nourished the algae. When the alewives migrate out of the pond in the fall, the phosphorus goes with them and is not available for next summer's algae.

Association President David Landry said if a state study showing that alewives potentially could remove up to 1,200 pounds of phosphorus a year from China Lake is valid, the little fish would do the equivalent of $3.5 million of remedial work.

"No backhoes, no riprap, no geotextiles -- just fish. And they work for free," Gray said.

In addition, he said, harvesting surplus alewives would bring revenue to the town.

This year, Vassalboro earned a few thousand dollars by selling alewife fishing rights on Webber Pond's outlet stream.

Retired game warden Roland Tilton, as knowledgeable about China Lake as Gray is about alewives, questioned introducing a fish that eats the zooplankton that eat the algae.

Other lakes where alewives are stocked have not seen water quality improvements, he said.

Gray and Landry agreed results have not been consistent from one lake to another, and more study is needed.

There is also the question of how the fish would get into China Lake.

In the early 1880s, before the Kennebec and Sebasticook rivers were dammed, alewives swam in from the ocean to spawn in China Lake and many other central Maine lakes, Gray said.

This summer's removal of the Fort Halifax Dam lets them again go up the Sebasticook to the mouth of China Lake's Outlet Stream, which runs through Vassalboro and Winslow. But there are six dams on the stream, none with a fish passage.

The state currently promotes fish migration by trapping and trucking. The method is labor-intensive and expensive, Gray said; it would not be practical for introducing enough alewives to make an impact in a lake as large as China.

Assessor William Van Tuinen was the lake association's second guest speaker. The audience of about 80, mostly lakefront property owners, listened in tense silence as he warned them the almost-completed revaluation will increase their tax bills.

BY MARY GROW
Kennebec Journal, 08/09/2008


Lakes: China Lake
Regions: Belgrade


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