Better fisheries through chemistry
Local waters treated for lamprey control
BIG BAY — The ongoing battle with sea lampreys went local recently, with U.S. Fish and Wildlife staff applying lampricides to local waterways in Marquette County.
Chris Gagnon, USFWS fish biologist, was on site June 29 at the Big Garlic River on Granot Loma, an expansive private residence where the river flows.
“This one’s pretty known for its trout population,” Gagnon said of the river.
Local anglers no doubt want it to stay that way.
Fisheries technicians applied the lampricide directly into the river at one spot while other work took place at Sawmill and Wilson creeks, he said.
“We’re kind of feeding all of them to match each other at the same time as they flow downstream,” Gagnon said.
Crews started that day at staggered times, with the goal of putting in a 12-hour “chemical bank,” he said.
The crews used TFM, which kills lamprey larvae in streams with little or no impact on other fish and wildlife.
Sea lampreys, which resemble eels, are native to the Atlantic Ocean.
Gagnon said they eventually adapted to the fresh water of the Great Lakes.
“I respect them for how resilient they are, how they’ve adapted,” he said.
Resilient or not, as non-native species, they don’t belong here.
Lampreys entered the Great Lakes through manmade shipping canals, and were first observed in Lake Ontario in the 1830s. Niagara Falls acted as a natural barrier to lampreys traveling farther west, but when the Welland Canal was deepened in 1919, lampreys gained access to lakes Erie, Huron, Michigan and Superior.
By 1938, they have invaded all the Great Lakes, eventually causing great harm to the lake trout fishery.
The lampricide program is contracted through the Great Lakes Fishery Commission to the USFS and Oceans Canada. Chemical control of sea lampreys began in 1958, and since then, the successful program has helped maintain the $7 billion Great Lakes sport and commercial fisheries.
Sea lampreys are unusual in the fish world in that they have cartilage but no bones and have scaleless skin. They don’t have paired fins, a lateral line and a swim bladder.
They also lack jaws, and this might be their most unusual characteristic. Lampreys’ round mouths form a sucking disk filled with sharp, horn-shaped teeth that surround a rasping tongue.
If that sounds unpleasant, consider what a lamprey can do when it attaches to a fish, using its tongue to rasp through a fish’s scales and skin to feed on blood and body fluids.
They aren’t parasitic, though, their entire lives.
Gagnon said the USFWS conducts such lampricide treatments to wipe out larvae in streams generally every three to four years because of their life cycles.
“They live for three to four years as non-parasitic larvae in the streams, so that’s why every three to four years we come back,” Gagnon said. “We’re targeting the young ones in the stream, while the adults, when they go out into the big lake to feed on lake trout and such, there’s nothing we can do.”
The lampreys return to the stream and spawn in the spring, starting the life cycle over again.
Gagnon said the larvae, which live and filter-feed in the sediment, sense the TFM when it’s applied to a stream, and eventually leave their burrows to search for fresh water to get away from the chemical. They then will die, usually within a few hours.
At the Big Garlic River Friday, the TFM setup involved a perforated tube so the chemical would be mixed evenly throughout the water, he said.
Treating streams isn’t always easy for the fisheries technicians.
“This is nice that we got a bridge crossing here, but there’s a lot of times where we are just bushwhacking chemical up to a mile through the woods,” Gagnon said. “It’s a physically demanding job.”
Jesse Haavisto, fisheries biologist for the USFWS, was in charge of June 29’s lamprey treatments at the Big Garlic.
The success of a treatment depends on the river, he said.
“Without treatment, every fall there would be basically a wave of lamprey heading out in the Great Lakes,” Haavisto said, with other fish being lamprey prey.
He noted that adult lampreys can be incidentally caught and killed during the treatments, but they’re not targeted.
The targets, Haavisto said, are ammocoetes — the lamprey larvae.
“They’re everywhere,” he said.
That said, what crews treat is limited.
“We only treat up as far up as we have to in the river,” Haavisto said.
However, work is performed before treatment day.
“Before we actually treat a river, we’re usually out here several days, taking water chemistries and also stream gauging,” Gagnon said.
Boards placed in the water give crews an idea of how much water they’re looking at for the treatment.
“The amount of water and the pH determines how much chemical goes in the river,” Gagnon said.
The Big Garlic River, and Sawmill and Wilson creeks, eventually merge, with the waters then flowing into Saux Head Lake, he said. However, the chemical dissipates once it hits the lake.
An outlet from Saux Head Lake to Lake Superior was recently treated as well, he said.
A bonus for the crews while they treated the Big Garlic was visiting the beautiful Granot Loma property, much of which is pristine woodlands
Fortunately, they received permission to go on private property. In fact, Gagnon said getting such permission has been needed for crews to perform their work.
“Most people up here are pretty good,” Gagnon said.
Other lampricide spots scheduled to be treated were the Carp and Pine rivers, and Harlow Creek, all Lake Superior tributaries. Applications were expected to be conducted until this week.
Also expected to be conducted from late June to this week was work by an USFWS/Oceans Canada assessment crew on the Huron, Slate and Dead rivers, Lake Superior tributaries as well.
Its work was to focus on estimating the abundance of lampreys in the rivers.
The information gathered will be used to determine the need for lamprey control.
Christie Bleck can be reached at 906-228-2500, ext. 250.