Who would have guessed the state would really do what I have been posting for years.
CORTLAND, N.Y. (AP) — Fisheries biologists who have been working to restore Atlantic salmon to Lake Ontario are now trying to restore the population of its natural prey as well.
Lake herring and bloaters were once plentiful in the cold depths of Lake Ontario, where they fed on plankton and invertebrates and made up an important link in the food chain. But overharvesting by anglers and competition from invasive alewife and rainbow smelt that arrived with the opening of the Erie Canal devastated the native prey fish. The last bloater, also known as deepwater cisco or whitefish, was caught in 1983, and native herring are found only in the lake's eastern end.
Now, in a collaborative effort between federal, state and Canadian authorities, scientists are rearing the prey fish in tanks and releasing tens of thousands of juveniles as part of a larger program to restore ecological balance to the lake and surrounding wetlands.
"It's a huge job," said Jim Johnson, director of the U.S. Geological Survey's Tunison Laboratory of Aquatic Science in Cortland, 30 miles south of Syracuse. "It's never been attempted before."
Because bloater had never been hatched and raised in captivity, the scientists at Tunison had to overcome a series of obstacles before they successfully reared and released their first brood of 10,000 fingerlings last fall.
The first problem was getting the eggs, spawned in 300 to 400 feet of water in the upper Great Lakes in January or February.
"You have to find the right person with the right gear to go out there," Johnson said.
The second problem was that the fish's air bladder bloats and the eggs are expelled in the water if you bring them up too quickly in a trawler net.
The next challenge was finding the right food for hatchlings half as long as an eyelash. "We had to improvise and grow our own live food because the commercial feed everyone thought would work was too big for their mouths," Johnson said. The researchers fed the newborns tiny brine shrimp, then weaned them onto a salmon-colored Japanese dry food called Otohime.
"It's small and it's a color they like," Johnson said. "They wouldn't touch the U.S. diet that's black."
Lake herring aren't nearly as difficult to rear. Adults are netted in Chaumont Bay at the eastern end of Lake Ontario and transported to the Tunison lab to spawn.
An $800,000 ultraviolet treatment building, built with the first year's allocation of Great Lakes Restoration Initiative money, allows scientist to bring wild lake herring and Atlantic salmon to the site without worrying about contaminating local waterways.
"Disease is a huge issue in the Great Lakes," Johnson said. "Ultraviolet treatment kills any disease organisms the wild fish may harbor."
The restoration initiative, launched by President Barack Obama with a $475 million budget allocation in 2010, focuses on toxic substances, invasive species, pollution, habitat and wildlife protection and restoration, and education and monitoring in Great Lakes areas of concern.
"Not only do lake trout rely on native prey fish to thrive, but it's also a good thing for the ecosystem as a whole because native species are better suited than the exotic ones," said Todd Kalish, the Lake Erie basin coordinator for Michigan's division of fisheries.
One building at the Tunison lab has 36 tanks of baby Atlantic salmon to be released into Lake Ontario tributaries as part of a restoration project for that species. U.S., Canadian and New York agencies have been releasing Atlantic salmon for years in Lake Ontario, the only Great Lake where they were historically found. In 2009, the first wild-born Atlantic salmon in more than a century were found in a Lake Ontario tributary, suggesting the species was establishing a naturally reproducing population.
Alewives are blamed for impairing reproduction of salmon and trout in Lake Ontario because they contain an enzyme that destroys the critical vitamin thiamine. The abundance of alewives has spurred a booming sport fishery in Lake Ontario as trout and salmon grow to trophy size gorging on the little fish, but the offspring of the trophy fish die of thiamine deficiency unless the vitamin is added at state hatcheries.
This fall, biologists expect to release 10,000 juvenile lake herring into Irondequoit Bay or Sodus Bay near Rochester and 15,000 young bloaters offshore from Oswego, Johnson said. Scientists will have to wait four to five years, when the fish are of breeding age, to see results.
But the odds of survival are good, he said.
"When they were eliminated before, it was a combination of overfishing and alewife becoming superabundant and out-competing them," Johnson said. "Now the alewife population is being hammered by the trout and salmon, so herring and bloater should be able to get a toehold again."