Sea lamprey population could soon boom in Great Lakes – Cleveland, Ohio

Cleveland, Ohio 2022-06-03 16:27:23 –

(WJET / WFXP / — The Great Lakes sea lamprey population could grow significantly over the next year or two, and it is currently unclear how quickly the population can be restored.

“They get caught in the mouth of a sucker filled with alien grotesque teeth …” That’s how Dr. Mark Garden, Communication Director and Legislative Liaison Officer of the Great Lakes Fisheries Commission, describes sea lampreys. There is no lost love there. “Just looking at the pictures shows that I underestimate how grotesque they really are,” he adds.

It may be ugly, but it’s not a direct danger to humans. It’s also not dangerous for dogs swimming in the Great Lakes. Sea lampreys eat warm-blooded animals. If they stick to humans, they are “just hooking a vehicle,” Garden said, and they’ll soon leave (they’re probably long enough for photos that can be posted ominously on the Internet. Will adhere in. Example). Long-distance swimmers across Lake Ontario are dissatisfied with having to pick up sea lampreys when swimming.

“Once again, they’re just riding in vehicles. If you’re not swimming across Lake Ontario, don’t worry,” Garden said. “Otherwise, they are afraid of you and they will not eat you because you are a warm-blooded animal.”

Taken on July 16, 2010, a scientist at the Hammond Bay Biological Station near Hulong Beach, Mississippi, has a female sea lamprey. Lamprey uses a disc-shaped mouth and sharp teeth to secure it to the fish and suck out body fluids. (AP Photo / John Fresher)

However, sea lampreys are a nightmare for fish. They attach with the mouth of a sucker and then use a thorny tongue to puncture the sides of the fish. They eat fish blood and body fluids.

“They are vampires,” Garden said.

Impact and life cycle

Each sea lamprey can kill over 40 pounds of fish during its lifetime. Before scientists developed chemicals and tactics to control lamprey populations, they killed 110 million pounds of fish annually.

“It’s much higher than the commercial catch rate at the time. Sea lampreys were catching more fish than humans when management efforts began,” Garden said.

And guys, can they breed? A female lamprey can lay up to 100,000 eggs. Add to the fact that the Great Lakes fish were protected from sea lampreys during evolution and therefore did not develop the ability to repel them. It’s not hard to understand why sea lampreys have had a dramatic impact on native fish populations since they invaded the Great Lakes in the late 1800s. By 1939, sea lampreys were all the way to Lake Superior, and by the 1940s, everyone had begun to understand how dire the situation was, Garden said. Fishermen and other stakeholders have lobbied the US and Canadian governments, and mitigation efforts have begun.

Scientists were looking for ways to get rid of the population.

“It’s easy to kill a fish with a common pesticide (fish poison), but we only use it as a last resort,” Garden said. Dropping pesticides into the water system kills all fish, including sea lampreys, lake trout, and walleye pollock. In the Great Lakes system, the cure would be worse than the disease. “

It was in 1957 that scientists used the “pickle jar” test to discover lamprey (the poison of lamprey). According to Gaden, scientists put two trout and lampreys in the same “jar,” introduce the chemicals, and then return in the morning to check the results. In many cases, both the fish and the lamprey were dead. Occasionally, only the fish died. Finally, after trying about 7,000 chemicals, I found the right one to kill only lampreys and lampreys (“Lampreys are primitive fish, and like other fish, lamprey chemicals. It cannot be metabolized, “Gaden explained.)

Sea lampreys spawn in rivers. Eggs are laid upstream of rocky areas, and hatched larvae swim downstream, where they are buried in silty sandy beach beds. They live there for about four years before they mature and metamorphose, becoming a parasitic form that causes devastating damage to large lakes.

Pandemic delays mitigation

Sea lampreys spawn in rivers, so the quick solution was to build a dam. Approximately 400 or 500 streams of the Great Lakes system are suitable for spawning sea lampreys. About 70 dams were intentionally built to control the spawning of lampreys. Other dams were built for other reasons, but are still effective in preventing sea lamprey spawning, Gaden said. Still, there are still a lot of streams for spawns. And that’s where ramp resides are key.

Lampriside is applied to streams and kills larvae hidden under the sand. It kills about 98% of the larvae. Because the larvae spend about four years in the stream (essentially harmless to the ecosystem at that stage of the life cycle), the Great Lakes Fisheries Commission treats 25% of the stream each year. In doing so, Gaden explained that they were killing “a four-year class at a time.” This will be about 100-120 streams processed by Lamp Reside each year.

By 2020, the Commission noticed an increase in the number of lampreys.
The Great Lakes, so it was increasing its treatment. However, after that, a pandemic occurred.

The pandemic limitation meant that the team could not step into the field to process the stream, which had a clear impact on the processing schedule. By 2020, the Commission was able to process only about 25% of the streams it was planning to process by the time the pandemic regulation came into force. When the pandemic restrictions were relaxed in 2021, the Commission processed about 75% of the streams that were scheduled to be processed in 2021. Now, in 2022, Gaden said the Commission will complete the entire Ogawa processing schedule.

Good news, bad news

Its short revocation of treatment is bad news for the Great Lakes. Those lampreys spend a lot of time swimming growing in lakes where fish can’t shake them off, eventually returning to lay 100,000 eggs each.

“We probably don’t really know until the end of this year or next year … The lampreys back in 2022 were the survivors of the 2020 field season. There are biologists monitoring spawning rates.” Gaden said. “Lampreys lay their eggs in late June, so we can see how 2020 shook later this year. It’s reasonable to see a surge after most treatments had to be postponed. . “

The good news is that the team had already stepped up their treatment a year before the pandemic.

“We happened to never be in such a good place to survive something like a serious pandemic,” Garden said. “It could be in contrast to Blip, who can bring us back decades and be aggressive over the next few years to push it down. I am cautiously optimistic about the moment. “

Sea lampreys prefer cold water, Garden said. But if the warming of climate change seems to be good news in the fight against sea lampreys, think again.

“Sea lampreys work well in cold water, and they go through in warm water,” Garden said. “In Lake Superior, in some of the cold streams that go nowhere, they live as larvae for up to 17 years before experiencing metamorphosis. In some lakes, such as Lake Erie, due to the warm environment. Occurs frequently. “

The Commission had already considered extending the treatment schedule by 30% due to rising temperatures. It is essential to be at least one step ahead of the sea lamprey.

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“If they bounce, they will wipe you out and it will take a very long time to get it back,” Garden said. But the garden was cautiously optimistic.

Sea lamprey population could soon boom in Great Lakes Source link Sea lamprey population could soon boom in Great Lakes

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