Bigger lake trout - are alewives the reason?

By DENNIS APRILL, Outdoor Perspective

June 21, 2009 03:22 am

— On the heels of some very nice-sized lake trout being caught under the Lake Champlain ice this past winter and a record laker weighed in at the Rotary International two weeks ago, there are many anglers who point to the alewife invasion as the cause.

After all, lake trout and Atlantic salmon now have a new and, at the present time, plentiful food source, even if it may be at the cost of losing a lot of rainbow smelt, or at least forcing the smelt to other locations in the lake.

Vermont fisheries biologist Shawn Good, however, doesn't see the alewife, a small non-native baitfish, as a plus. He writes in Lake Champlain Angler Forum, "The apparent surge in growth and size of trout and salmon in Champlain cannot be irrefutably connected to their feeding on alewives. As a matter of fact, it's more likely related to something else — and that is a successful sea lamprey control program."

Good goes on to point out that with lamprey control in most New York and Vermont rivers, lake trout are living longer, thus growing larger; and that the arrival of alewives at the same time as the lamprey control program doesn't mean the alewives have lead to the larger fish; and the past smelt population would have provided a forage base for lakers as well.

Good also adds that because alewives go through boom and bust cycles (2008 winter die-off a mild example), if lake trout and salmon become focused mainly on alewives and smelt numbers are low, and the alewives crash, "Suddenly, we will have skinny fish."

There are other downsides to the alewives, according to Good. In Vermont, hatcheries plan two years ahead on stocking numbers. If those numbers are based on a large alewife food base and in the meantime the alewives crash, what happens to all those raised fish? Are they set free with a low chance for survival?

Finally, Good cautions, "The original Lake Champlain Salmonoid Restoration Program's goal was to restore natural reproduction with lake trout and salmon." He goes on to say, "That may no longer be possible due to Early Mortality Syndrome (EMS), a maternally transmitted, non-infectious disease that causes up to 100% mortality in the offspring of landlocked Atlantic salmon that feed primarily on alewives. Lake trout have also been shown to suffer reproductive failure when they eat mostly alewives."

The culprit is that female salmon become vitamin B-1 deficient from eating large quantities of these baitfish.

Not everyone is convinced the lamprey control program should be totally credited for the larger lake trout. Plattsburgh's Mickey Maynard, owner of Lake Champlain Fishing Charters, says his clients, as of last Thursday, have taken 357 lake trout, most with lamprey scars, though Maynard adds, "Most are old scars."

Maynard, whose Web site www.lakechamplainangler.com is one of the most fishing-extensive for the region, thinks, "It's a combination of a changing forage base along with more thorough fish management, i.e. lamprey control, that has led to the larger fish."

His largest lake trout so far is a 13-pounder.

"Of the few fish we don't release, their bellies are full with alewives, the main food by a 3-to-1 ratio over smelt."

This weekend's Lake Champlain International Fishing Derby that brings thousands of anglers competing in a dozen or so categories including salmon and lake trout should give us a better read on how much larger these two species and others are, if at all, in the new alewife era.

Field Notes
â A state record brook trout has been caught in Raquette Lake.

The trout, according to reports, was certified by DEC and weighed in at 5 pounds, 4½ ounces. It was 21 inches long with a girth of 15 inches and caught by Tom Yacovella.

â New York's Free Fishing Weekend is this coming one: June 27 and 28.

Anyone can fish in the state with or without a license, as long as he or she follows the regulations.

E-mail Dennis Aprill at daprill2000@yahoo.com and check out our Web site at www.pressrepublican.com/0105_outdoor_perspective for more photos and past articles.

Copyright © 1999-2008 cnhi, inc.