November 1, 2011

Atlantic Salmon returning to central New York’s Salmon River

Associated Press

PULASKI, N.Y. (AP) — Native Atlantic salmon are once again reproducing in the wild in central New York’s renowned Salmon River, where anglers travel from across North America and overseas every autumn to reel in hatchery-bred Atlantics as well as non-native chinooks, cohos, brown trout and feisty steelheads that swim upstream from Lake Ontario.

After more than a century without a wild-breeding population, this is the third year in a row that researchers from the U.S. Geological Survey have found young Atlantic salmon in the river, said USGS scientist Jim Johnson. When the young mature, eggs will be taken from some to propagate at the USGS research lab in Cortland, he said...

Lake Ontario once supported the world’s largest freshwater population of Atlantic salmon. But the fish vanished in the late 1800s as a result of overfishing and habitat destruction. Government agencies in the U.S. and Canada have maintained an Atlantic salmon fishery by the annual stocking of millions of hatchery fish, but the fish haven’t been able to reproduce in the wild because of a thiamine deficiency caused by eating alewives, an invasive species. Alewives contain an enzyme that destroys thiamine, also known as Vitamin B1.

“After Atlantic salmon and lake trout were extirpated, there was no longer a major predator to eat the alewives in Lake Ontario and the population exploded,” said Fran Verdoliva, Salmon River program coordinator for the state Department of Environmental Conservation.

Pacific salmon — chinook and coho — were brought in from hatcheries to control the alewife population in Lake Ontario in 1968, and brown and steelhead trout were added in the 1970s.

“The sport fishery developed out of what started as biological control of invasive species,” Verdoliva said...

It’s unclear why Atlantic salmon are now reproducing in the wild, but a decline in the number of alewives coupled with a rise in numbers of another invasive species called the round goby may have something to do with it.

“Gobies are high in thiamine,” Verdoliva said. When salmon eat gobies, it may increase their thiamine level, countering the ill-effect of alewives, he said...

Read the full story at link.

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See an interesting slide show about Common Reed in the Southeastern US by Bill Overholt et al. at link.

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