Lamprey control program a part of saving Great Lakes fishery

This small lamprey is in the transformer stage and would enter Lake Erie in the coming months. It was discovered by Kevin Sullivan in the Otter while kayaking the river as part of the treatment assessment. Jeff Helsdon photo

Jeff Helsdon, Local Journalism Initiative Reporter

Sea lamprey have been called the vampires of the Great Lakes.

This invasive eel-like species’ purpose in life is literally to suck the lifeblood out of fish to sustain itself. Since Great Lakes fish haven’t evolved to cope with this invasive species, it has caused enormous havoc before control programs began decades ago.

Astute observers of the Otter Creek noticed it flowed bright green for a few days last month. Bright green isn’t typically thought of as a healthy colour for Ontario rivers, but in this case, it was part of the lamprey control program run by the bi-national Great Lakes Fishery Commission.

Fisheries and Oceans Canada lamprey control crews started treatment of the Big Otter Creek on Oct. 17. The initial application of 3-trifluoromethyl-4-nitrophenol (TFM) was on the Otter Creek where it crosses Cornell Road near Otterville. Also known as lampricide, TFM concentrations are boosted where the Otter crosses Middletown Road and County Road 13, in Tillsonburg, near Coronation Park, and at the Eden Line.

“As it moves downriver, it loses concentration, so we have to boost it, said Shawn Robertson, treatment biologist with Fisheries and Oceans Canada.

A week later, crews were nearing completion of their work but were still testing the Otter’s TFM concentrations in Vienna. The goal is to have TFM concentrations at a level to kill larval sea lamprey. The crews tested the pH of the water, as lamprey are more sensitive to the acidity of the water than native fish. The other goal is not to kill non-target species.

Aquatic technician Kevin Sullivan’s job was to travel down the river in a kayak, observe for kill of non-target species and ensure there were no backwater areas or inlets where the larval lamprey can escape.

“Just to make sure they don’t have fresh water to go into,” he said.

Lamprey larvae live three to four years as larvae in rivers, feeding on algae and dead plant material. Then, as they transform into adults, they move towards the mouth of the river and spend 1.5 years feeding on fish as adults. Having a lamprey attached often kills fish, and one adult can kill up to 40 pounds of fish in its life. The adults return to the river, making a horseshoe-shaped depression in the gravel substrate, spawn and die.

Typically, the Big Otter is treated in the spring, but water levels were too high this year.

“The snow melt had gone and we got a bunch of rain, so it was too high,” Robertson said. “And it was too cold. If it’s too cold, it affects the way the lampricide works.”

The Big Creek treatment did proceed in the spring.

One of the first invasive species

The buzz around Great Lakes invasive species grew when zebra and quagga mussels colonized the lake starting in the late 1980s, but the sea lamprey has been around much longer than that.

Sea lamprey reached Lake Ontario via the Hudson River and Erie Canal in the 1800s, contributing to the demise of Atlantic salmon in the lake.

However, Niagara Falls stood in the way of sea lamprey reaching further into the Great Lakes for decades. Then, the commercial fishery for lake trout and whitefish in Lake Erie mysteriously began declining in the 1920s and 1930s. The decline coincided with the expansion of the Welland Canal, which started in 1919 and was completed in 1932. The commercial fishermen of the day were perplexed, and the scientists didn’t have any answers.

The first recorded lamprey found in Lake Erie was in 1921, when a commercial fisherman pulled his nets and found one attached to a whitefish. Six years later, another was reported on the American side of the lake. Then, in 1937, several youths exploring a river in Lake Michigan found it swarming with lampreys and reported the discovery. Lamprey populations in the lower four Great Lakes exploded from there.

As a result, the commercial catch of lake trout dropped from 2.2 million pounds in 1940 to 760,000 pounds in 1946.

Fisheries scientists and politicians started to take notice. Research began at the Ann Arbor, Mich., U.S. Bureau of Fisheries lab in the late 1940s to find a solution. The first challenge was identifying the life cycle of the sea lamprey, which little was known about at the time.

Barriers and dams were experimented with, but these also stopped the passage of spawning fish. Research then focused on identifying a chemical that would kill lampreys without harming native fish.

“Killing fish is not that difficult,” said Dr. Marc Gaden, executive secretary of the Great Lakes Fishery Commission. “There are chemicals out there that will kill fish effectively. What is difficult is killing exactly the fish that you want to kill and not harming the fish you want to leave in the river or lake.”

After five years of looking for such a chemical, TFM was found in 1957.

Another mystery was solved in the 1950s – why lamprey took a century to pass through the Welland Canal, which opened in 1829. The early canal was not much more than a ditch and was fed from water that came from the middle of the Niagara Peninsula. There was no flow from one lake to the other. When the canal was upgraded in the 1920s, it used water from Lake Erie, and lampreys look for current. Essentially, the upgrade transformed the canal into a river.

The Great Lakes Fishery Commission

With the demise of the Great Lakes fishery, political pressure grew for a solution involving both Canada and the United States. The formation of the Great Lakes Fishery Commission in 1955 served as a catalyst for advancing fisheries science and implementing the sea lamprey control program.

Efforts for international cooperation date back to shortly after it was recognized there was a sea lamprey problem in Lake Ontario in the 1890s. A treaty was proposed in 1908 that established a bi-national committee to address lamprey and fisheries issues. Canada implemented the treaty’s recommendations, but the U.S. didn’t, causing Canada to cease following them. The treaty was dead by 1911.

By 1954, the decimation of fish by lamprey was dire enough in the Great Lakes that Canadian and American politicians came together again with the intent of intensifying work on the Great Lakes fisheries and lamprey control. After trying more than 40 times over the last six decades for international cooperation on fisheries, the United States and Canada signed the 1954 Convention on Great Lakes Fisheries. The following year, the Great Lakes Fisheries Commission (GLFC) was established.

Since that time, the GLFC has evolved to assist with other scientific endeavors to protect fisheries, such as research on invasive quagga and zebra mussels, and a risk assessment of the Asian carp invasion.

Other control methods for lamprey have also advanced since the 1950s. An inflatable dam on Big Creek is timed to block the passage of lamprey but is deflated to allow spawning fish to pass. Other dams have been installed on smaller tributaries, such as Little Otter Creek, which fish can jump over but lampreys cannot.

Today, the Great Lakes fishery has rebounded and combined commercial and recreational fisheries are worth $7 billion to the economies of the Great Lakes states and Ontario.

“We brought lamprey under control, probably beyond the wildest dreams of the people who set up the commission,” Gaden said. “The sea lamprey population was reduced 95 per cent.”

As for eradication, Gaden said that with each female lamprey laying 100,000 eggs, it’s nearly impossible to eliminate the last mating pair using current technology. The commission and other researchers are looking at genetic manipulation to have lamprey produce all offspring of one gender, thereby thwarting reproduction.

“Eventually, you could use genetics as a control technique,” Gaden said, estimating it would take 60 years for eradication.