Limnology, unfortunately, can’t always be about the fieldwork. For every sunny day spent out on a boat in a lake, weeks and months pile up as our students and faculty retreat back to the lab and their computers to try to make sense of all the data they’ve collected.
Even though she’s only an undergrad, Sam Neary already knows this well – which is why I recently found her down in the sweltering Wet Lab cutting the stomachs out of long-frozen yellow perch.
Sam was working on fish caught in a gill net and placed in CFL deep freeze last year, but has years and years of perch samples to get through. What she discovers in their stomachs will help scientists better understand how an invasive zooplankton, called spiny waterflea, is impacting perch populations in the Yahara lakes.
“I’m checking diets to see what [the perch are] eating and how that’s changed pre and post spiny waterflea invasion,” she explains to me as she slowly cuts into yet another perch belly. “And if they’re eating the spinies – which they are, I’ve seen them – we want to see if that affects their growth.”
The problem, Neary says, is that a large percent of a spiny’s body mass is its trademark pointed tail. Previous research suggests that the tails don’t get broken down in a fish’s stomach, which means fish are, technically, full, but aren’t absorbing any (calories or nutrients) from the bulk of their meal.
That’s an important question to ask, considering Wisconsin anglers consider perch one of the state’s top table fish and spiny waterflea populations in Lake Mendota are booming.
Sam will be a senior this fall and hopes her zoology degree will lead to a career in marine biology. For the time being, though, she can’t think of a better place to be than the Hasler Lab basement, surrounded by partially dissected perch and partially digested zooplankton.
“All of my friends are working at restaurants or the mall,” she says. “And I’m like, ‘I’m gonna go spend eight hours gutting fish.'”