Use the natural instincts of sea lampreys against them

The sea lamprey is a destructive invasive species that has threatened native Great Lakes fisheries for decades. Several research teams at Michigan State University are finding ways to harness the natural instincts of sea lampreys to monitor, capture and control them.

Chemical signals

Weiming Li, a professor in the Fisheries and Wildlife Department of the College of Agriculture and Natural Resources, studies sea lamprey mating chemical signals called pheromones.

“Sea lampreys have had half a billion years to refine their chemistry,” Li said. “If we can find a way to disrupt their chemical signals, it might be more effective in controlling their population. “

So far, Li and his team have discovered three pheromones. Sea lamprey larvae release a pheromone that attracts migrating sea lamprey adults to spawn nearby. Once on the spawning grounds, mature males release two pheromones that attract females to mate.

“Once a sea lamprey detects male competition,” said PhD student Skye Fissette. “He will release more pheromones, possibly in an attempt to compete with other males for mates.”

Trying to test sea lamprey pheromones in the field is difficult, as sea lamprey can detect very low concentrations of pheromones in water.

“Sea lampreys can detect even lower concentrations than chemical instruments can detect,” Li said, “It’s really amazing.”

Fear tactic

When a sea lamprey is attacked, damaged tissue releases an alarm signal scent that acts like warning cones on a highway, warning migrating lampreys to move into areas at risk.

In smaller bodies of water, researchers led by Michael Wagner, associate professor in the Department of Fisheries and Wildlife at the College of Agriculture and Natural Resources, combine the red flag with a passive barrier to capture the sea ​​lamprey while letting native fish swim through. The strategy presses the lamprey to escape, but instead guides them to an eel ladder, a device that forces the sea lamprey to squeeze through a series of stakes climbing up a steep ramp that extends out of water. At the top, the sea lamprey falls into a trap and is collected for removal.

Even a sea lamprey crossing the barrier is too much.

“Males secrete powerful pheromones that will attract females from a great distance and if they are found, a female can lay 100,000 eggs and will infest a stream very quickly,” Wagner said. “We hope that the development of this device will help the Great Lakes Fishery Commission achieve its goal of overtaking native fish while blocking sea lamprey to protect our fisheries.”

Difficult situation

Adult sea lampreys attach themselves to fish to feed on their blood. Xiaobo Tan and Nelson Sepulveda, professors in the Department of Electrical and Computer Engineering, are developing “smart” sensor panels that take advantage of a sea lamprey’s sucking instinct to record the mechanics of attachment.

To properly design the smart panels, Hongyang Shi, a doctoral student, built a prototype containing detection devices to understand the dynamics of sea lamprey suction pressure. The researchers wanted to know if the sea lamprey’s suction was uniform across the suction disc or if it was concentrated in the middle or outside of the ring. It was also important to measure the suction force of a sea lamprey.

“We were surprised to learn that the sea lamprey only sucks as hard as it should,” Tan said. “Which makes sense, he doesn’t want to use his energy that is otherwise needed to find a mate and reproduce.”

The research was recently published in PLOS ONE.

“After more than half a century of research and development, we are currently focused on using the most obvious lamprey-specific trait (oral aspiration) to control lamprey,” said Christopher Holbrook, specialist biologist in fish to the US Geological Survey. The Hammond Bay Biological Station located near Millersburg, Michigan and a contributor to this work, “Modern technology, especially advances in robotics and new materials, makes this possible.”