Lake trout find new home in Erie

Catawba Island, Ohio — A second round of lake trout were stocked in Ohio’s waters of Lake Erie on April 8-9 at Catawba Point and into Fairport Harbor on April 10-11.

This is the beginning of an expanded effort by the Great Lakes Fishery Commission’s Cold Water Task Group to re-establish a population of this cool water native fish species and provide recreational fishing opportunities.

According to a press release issued by the U.S. Fish and Wildlife Service, these advanced yearling fish are part of the first batch of fish hatched and raised at the renovated Allegheny National Fish Hatchery in Warren, Pa., since 2005, when a fish virus forced it to close and destroy its brood stock.

Back in November, 82,400 fingerlings were stocked at Catawba and 41,300 at Fairport Harbor using surplus fish that were hatched last spring, reducing competition for space in the hatchery and allowing enough room for this current crop to grow into yearlings, the preferred stocking size.

This may be a newly created technique that will be repeated, according to Larry Miller, hatchery manager. He says the fish that are being used in Lake Erie came from the Seneca Lake Wild Strain, also known in the hatchery trade as the Finger Lake Strain,which closely match the lower Great Lakes genetics.

The Vermont State Fish Hatchery System took some of these and created a variety of lake trout called the Lake Champlain Domestic strain, which is more shallow water tolerant and likely the best match for Lake Erie.

Unfortunately, despite approximately 30 years of stocking lake trout in Ontario, Pennsylvania, and New York waters of Lake Erie, there has been little evidence of any natural reproduction and poor long term survival of any other lake trout strains used thus far.

Because of these failed attempts to establish a breeding population in the lake by only stocking the eastern end, a new strategy of also stocking western Lake Erie near former historical spawning areas is slated to be tried for a period of about five years, according to Kevin Kayle, supervisor of the ODNR Division of Wildlife’s Fairport Harbor Fisheries Research Station and co-chair of the Cold Water Task Group.

At that point, survival rates should start to be evident by fish being caught and this new effort can be evaluated further. Each fish has its adipose fin clipped to recognize it as a stocked fish and tiny, coded, wire tags have been inserted into the nose of every fish to allow data to be electronically read in the lab that will provide genetic strain, stocking dates, age, growth, and migration information of each recaptured fish.

Lake Erie may not be as welcoming now to lake trout as it was in the recent past as evidenced by other deep water fish species undergoing population declines, possibly due to an expanding “dead zone” and higher than desired sea lamprey populations.

Biologists predict cool water fish numbers will decrease further if average water temperatures climb due to climate change, especially in Lake Erie, the southernmost Great Lake, in favor of warm water species.

With total reactive phosphorus levels reaching record highs in western Lake Erie in 2011, the algae blooms have added to the size of the dead zone, an oxygen-depleted layer of cool water below the thermocline. Coldwater fish species seek refuge from warm surface water temperatures during the summer but can die from these low dissolved oxygen levels.

These species, which include lake whitefish, burbot, silver chubs and lake trout have undergone significant population declines over the past 10 years after strongly rebounds beginning in the early 1990s. Lake whitefish have not had significant reproduction since 2003. Commercial catches are down 75 percent over recent higher landings as this year class is fished out of the lake or dies of natural causes.

Commercial burbot catches were down to 1,308 pounds in 2012 and the silver chub, a minnow reaching several inches long, has declined 95 percent in trawling samples.

Sea lamprey wounds on fish, a method to assess their impact on the fishery, were at 10.1 per 100 fish in 2012 – twice as high as the goal of 5 per 100 fish (or less). Wounding rates have exceeded this goal 17 of the last 18 years.

Unfortunately, lake trout are sea lamprey’s favorite prey and largely responsible for the collapse of this fishery on all of the Great Lakes after the Welland Canal opened and allowed them passage around Niagara Falls in 1921.

But Jeff Tyson, ODNR/DOW Lake Erie Fisheries Administrator at the Sandusky Fisheries Research Unit, has hopes that the more shallow water tolerant lake trout strain may have the best chance to be better able to avoid the sea lampreys, which stay in colder, deep water.  

The annual migration of these fish may put them in shallow water to feed on abundant emerald shiners in the cool months, then return to deeper water in the summer and resume feeding on rainbow smelt.   

An addition of approximately 20,000 lake trout were scheduled to be stocked daily from April 15-18 in Lake Erie at Erie, Pa., and 40,000 more are to be released offshore from a boat near Dunkirk, New York, during the first week of May.

The Ohio Division of Wildlife is also considering the possibility of off-shore stocking in future years using a commercial ferry boat to haul the fish hatchery trucks closer to chosen spawning reefs. 

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