Wildlife Watch: Brook floater

Published: Aug. 16, 2022 at 2:47 PM EDT
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WINOOSKI, Vt. (WCAX) - Vermont’s waterways are filled with freshwater mussels, although it’s recommended you don’t eat them.

Some of them are endangered and that includes the brook floater.

On the banks of the Winooski River, Vermont Fish & Wildlife Biologist Mark Ferguson has his head down looking for freshwater mussels.

“This is kind of a hotspot. The Lake Champlain tributaries are actually the center for mussel diversity in the state,” Ferguson explained.

He is quick to spot a couple-- the pocketbook and the Eastern elliptio-- but there is one freshwater mussel that is found in only one location.

“Brook floaters are only found in the West River,” Ferguson said.

It’s one of the most endangered freshwater mussels, not only in Vermont but in North America.

“It’s an interesting creature, the brook floater. Actually, in the ‘90s, it was known to be fairly abundant, one of the more abundant species in that system. That has changed over time of the last 30 years it experienced a drop in its abundance. Just looking at comparisons to the surveys in the ‘90s to another one that was done in 2008, we have seen more than a 75% drop in the abundance, meaning we have less than one-fourth the amount of the number of brook floaters that we had back then,” Ferguson said.

Ferguson says the reason for the decline in population is not clear.

“We know that there are a number of threats that they face but which of those are the biggest factors in the drop is kind of an unknown and it hard to get at those questions,” Ferguson said.

He says the river flow in the tributaries of the Connecticut River as well as predation are things that normally impact the population.

“Back in the ‘90s, there were a lot of shells on the shore, some of them have been there a while, actually covered in sediment, so been there quite a while. But I’m not really seeing that level of predation today which suggests to me that the muskrats must not be finding them either,” he said.

And Ferguson says these critters are needed because they are a part of the ecosystem.

“They are filter feeders, they are sedentary. They are sitting on the bottom and they are filtering the water. They do that to get their oxygen, to get their food particles,” he said.

Now, biologists like Ferguson are working to grow the population of the brook floater.

“Generally when we look at trying to get species off a list, there are a number of ways we do that. One is habitat improvement. Another is just trying to increase the number of animals, that might be through propagation or improving their reproductive habitat. So for the brook floater, not knowing exactly why they declined is why we have struggled to get this one into a better shape than it is,” he said.

If you see a brook floater, Vermont Fish and Wildlife asks you to contact them.

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