LISTEN: Inside a leading research hub on Great Lakes sea lamprey control
Sea lampreys are nightmare material. They’re long, slimy, eel-like fish and have a suction cup mouth, lined with rows and rows of teeth.
At the Hammond Bay Biological Station, run by the US Geological Survey, I get to see a full-grown sea lamprey for the first time.
“Oh wow, they’re huge! It’s like a little alien.”
Station Director Nick Johnson explains that in a lamprey’s first year, it goes from the size of a pencil to...
“...to the size of a... I’m not sure what the size really is... [laughing] It’s big!”
We both agree it’s kind of hard to describe a sea lamprey. The blood-sucking parasite is invasive in the Great Lakes. It makes a living by latching onto gamefish and slowly draining them of fluids.
“That tongue has raspy teeth on it, and they use it like a piston,” Johnson said, holding up a male sea lamprey. “They piston a hole into the side of a fish to get access to blood.”
A single sea lamprey can kill up to 40 pounds of fish a year, feeding on lake trout, whitefish, walleye, cisco and salmon.
At the turn of the 19th century –when the Welland Canal connected Lake Ontario to Lake Erie– sea lampreys crossed into the Great Lakes. They thrived, and by the 1940s, lampreys threatened to completely collapse Great Lakes fisheries.
It was under these bleak conditions the Hammond Bay Biological Station was established by congress in 1950. Here, Johnson said researchers screened and advanced two of the primary control methods used today to eliminate sea lampreys.
The first is a chemical “lampricide” called TFM. It’s routinely applied by the US Fish and Wildlife Service to rivers around the state. The lampricide targets sea lamprey larvae before they can get into the Great Lakes and become blood-sucking parasites.
“Every batch of lampricide that’s manufactured comes [to Hammond] first,” Johnson said. “We do quality assurance tests and run live bioassays to make sure it kills lamprey and not trout. Then, we certify it for use before it can be used in rivers.”
The second method was developed at the station, prior to the lampricide. Traps, often placed near dams, annually capture 30,000 lampreys. They’re removed from Michigan waters as they’re returning to rivers to spawn.
“This style of trap can be pretty effective,” Johnson said. “They’re swimming around, trying to find a way through the dam. Basically, these little bars allow them to get in, but then don’t allow them to get back out.”
Johnson said the lampricide, traps, and physical barriers like dams work in conjunction to form the backbone of sea lamprey control. The traps also serve as a gauge to measure the effectiveness of control programs.
“A lot of these traps sites have been operated for over 50 years and provide a long-term data set and the overall trend of whether lamprey populations are going up or going down,” he said.
Sea lamprey control has been heralded as a success in invasive species management.
It’s unlikely we’ll ever completely get rid of sea lampreys in Michigan, but their populations have dropped by more than 90 percent since the use of lampricide and traps.
The biological station is still working on protecting native fish and improving sea lamprey control methods.
For example, researchers are looking to pheromones to lure unsuspecting lampreys into traps, and in another program, they’re releasing sterilized males. The sterilized lampreys no longer feed on fish, and after “reproducing,” a sterile male will die.
“They're still fully engaged in trying to reproduce,” Johnson said. “They think they're doing well. It’s kind of like maybe the next Romeo and Juliet on lamprey – they spawn, they die, and they don’t the end of the story, which is all the eggs they spawned and fertilized die.”
As we walk through the halls of the station, we reflect on Hammond Bay’s contributions. This station essentially saved Great Lakes fisheries.
“[TFM] was a gamechanger,” Johnson said, pointing out a framed photo depicting the first use of lampricide in Elliot Creek. “The fishery was lost in lakes Huron, Michigan, Erie, and Ontario. There were still some native fish in Superior. But this was pretty much the end of the... if they didn’t find it when they did, it would have been too late.”
Millersburg – a village of 200 people, 15 miles south – is the closest town to the station. Johnson said the station’s remote location makes it difficult to staff, but that’s kind of the nature of biological research.
It happens in some of the most inconspicuous places, but it’s from these places that some of the most “game-changing” work can emerge.