GRAND RAPIDS, Mich. (WOOD) — There is an environmental push across the Great Lakes to break up some barriers that prevent native fish from reaching their spawning grounds, but it must be done carefully to not give invasive species more opportunities to spread.
Researchers at the Great Lakes Fishery Commission believe they have found a tool to help: combining new technology with an ancient tool, the Archimedes screw.
The GLFC has recognized 494 “lowermost barriers” across the Great Lakes basin that are being considered for projects. Removing the barriers would help native fish move more freely across our waterways, but could also expose them to more invasive species, notably the sea lamprey.
Sea lamprey are not a new threat for the Great Lakes region. The parasitic fish are native to the Atlantic Ocean, but by the 19th century had made it into Lake Ontario. Niagara Falls served as a natural barrier to protect the other four Great Lakes, but changes to the terrain, including the Welland Canal, eventually let the lamprey invade all five Great Lakes.
Sea lamprey were first found in Lake Michigan in 1936 and by the 1950s had shown to be a major disruption in the lake’s ecosystem, killing off an estimated 110 million pounds of fish each year.
The GLFC was launched in 1954, primarily to solve the sea lamprey problem. After a few years and thousands of experiments, scientists developed an effective poison called TFM that kills off lamprey and sea lamprey larva while leaving other fish species unharmed. However, it’s not 100% effective. Biologists today believe the Great Lakes’ sea lamprey population has been cut by 90% by the lampricide.
Still, it’s important for the ecosystem to prevent as much spread as possible.
Dan Zielinski and his team at the GLFC are working on a project called FishPass that will replace a dam on the Boardman River in Traverse City and use a device to sort which fish to let through and which to trap.
“We worked with Whooshh Innovations, which is a company out west. If you’ve ever looked up the salmon cannon, that’s what they’re primarily known for. But they also have another tool that is an imaging tool where you essentially slide a fish down a wetted ramp. It takes about 18 images of them. And we worked with colleagues at Central Michigan University to develop computer learning algorithms that essentially takes those images and can identify whether it’s a sea lamprey or not,” Zielinski told News 8.
The team conducted imaging research on more than 1,000 different local fish species and were able to fine-tune the programming to identify a sea lamprey with “greater than 99% accuracy.”
While the imaging center worked, the machine still had two issues getting fish onto the ramp because it required manpower. For one, the goal is for the machine to be automated and running around the clock. Secondly, interactions with humans can impact their breeding cycle.
“The current way to be able to selectively pass fish is through manual trap and sort. You have to collect fish into a trap. They sit there for you, potentially a day or even a week. Then, they have to be handled by humans to identify whether it’s something you want to pass or not,” he said. “It causes a lot of stress on the fish. It delays their migration upstream. So even if you do pass them, they may not spawn because they’ve been stressed out or they missed the time that they needed to meet other cohorts in that same area. Having something that can provide a continual opportunity for passage is what drew us to the Archimedes screw.”
The screw is a simple machine that was allegedly invented by Greek scientist Archimedes around 234 B.C. The screw is composed of a pipe set in water at a 45-degree angle. Inside the pipe is a helix-shaped auger. As it spins, the auger traps the water from the bottom of the pipe and lifts it up along with whatever else is floating inside. With a large enough auger, the screw can pull water and, theoretically, fish.
Zielinski said early field tests show that the Archimedes screw was “fairly fish friendly.” The GLFC plans to run another test in a full field setting next year.
“It will be an open river system near a barrier and looking it if we can attract fish into the Archimedes screw so that they can be passed,” he said.
While he is hopeful that tests will show that the tool can be effective, Zielinski knows it’s not the only solution needed to safely open up Great Lakes waterways.
“It’s not going to be one of these tools that’s going to be applied to all the sites,” Zielinski said. “It’s going to be a mixture of different tools because, historically when you look at all of these different sorting tools — there have been a lot that have been developed over the last 50 to 100 years. They tend to max out at being 70 or 80% effective for a specific species. What we’re trying to do is learn how we can identify what’s the optimal suite of tools. How can we combine these?”