They’re long. They’re ancient. Their hideous whorl of a mouth is a “vortex of pain.”
But to Kate Buckman, they’re misunderstood and adorable – and vital to the ecosystem of the Connecticut River watershed.
That’s what she tells the volunteers about to join her on a wading expedition in Roaring Brook, a Connecticut River tributary in Glastonbury, Connecticut, to survey sea lamprey nests.
“If you leave with one thing today, I hope it's a better appreciation for lamprey and their role in what they do in their environment,” Buckman said.
Buckman is an aquatic ecologist with the Connecticut River Conservancy, and this year is the sixth that she’s leading surveys of tributaries in Connecticut, Massachusetts and New Hampshire to count sea lamprey nests.
Sea lampreys, Buckman explains, begin their life in freshwater before leaving for the ocean to attach to and feast on larger fish. Eventually, they return to freshwater – like the Connecticut River and its tributaries – to build nests, spawn, and die.
Their nests, built of substrate like rocks from the river bottom, end up creating habitat for insects and insect larvae, a major form of sustenance for watershed wildlife. Then, when the lampreys die, they’re fed on by everything from eagles to detritivores – organisms that feed on decomposing matter – to “anything that needs a little snack,” Buckman says.
“[Lampreys] are native to the Connecticut River watershed. We want them here. They’re ecosystem engineers,” Buckman said. “They bring this huge pulse of nutrients to the watershed.”
The data collected from the nest surveys “is actually really valuable to let us look at sort of long-term patterns in nesting,” Buckman said. “It helps us with an overall view of how migratory fish are doing in our watershed.”
Volunteers walk downstream in a line spanning the width of the brook, looking for piled-up stones next to a large rock and an “egg pit,” the telltale signs of a lamprey nest.
At one point, Buckman stops the group to examine a candidate.
“These rocks are a little small for lamprey,” she said. “I actually suspect what this is is, potentially, an older fallfish nest. Fallfish are a minnow-like species, they get kind of big, but they actually build like pyramid-type piles of pebbles to nest in.”
Later, Buckman’s colleague, Stefanie Farrington, stops to examine what could be a lamprey – but ends up being a stick.
“I’m also currently playing the ‘stick or lamprey’ game,” Buckman said. “They do kind of look like sticks.”
Ultimately on Tuesday, Buckman and the group find no lamprey nests or lampreys during the course of their survey.
It’s not entirely unexpected, she said, as lamprey may be in a down year. The Holyoke Dam on the Connecticut River in Massachusetts, she said, had only had 8,000 lamprey counted as having passed through this year so far, compared to 17,000 last year.
“There are a lot of reasons why that can be happening. One, maybe the lamprey population in general is lower,” Buckman said. “Two, does anyone remember what last summer was like? Droughty.”
River levels have been low, too, she said.
“And they've been warm, and that has an impact not only on the adults coming upstream now – they're missing some of their cues, potentially – but also on the young that were overwintering and living for a couple of years in the fresh water,” Buckman said. “When you have rivers that are really low and really hot, some of the habitat that normally would host the young lamprey is maybe not as suitable anymore.”
Still, Buckman said, a data point of zero is an important value to record.
“If we are seeing a year like this where there's zero nests in a spot where we have seen them previously, that’s a clue towards looking for what might be driving these population level differences, and whether that is something that we as humans have the ability to alter in a way that would benefit the watershed and the river system and the lamprey,” Buckman said.
“Even though it's disappointing on the human side to go out there and not see what you're looking for, it's really important to have those trends of up and down and yes and no to understand what’s happening,” she said.
Buckman will lead four more lamprey nest surveys this season: one more in a different section of Roaring Brook; two in the Sawmill River in Montague, Massachusetts; and one in the Ashuelot River in Hinsdale, New Hampshire.
She hopes the surveys help raise awareness about what she calls an “underappreciated” native fish.
“They're cool!” Buckman said. “They're just wild-looking animals, and they feel so foreign to us as humans, that there is definitely a fascination around them.”
“I actually really love getting people out here to walk in a stream and look for nests and learn something about lampreys,” she said. “I think we're sort of moving the needle on that.”
