Field Samples: What Do Fish Do When People Move Into the Neighborhood?

Field Samples is a Q&A with presenters at our weekly Wednesday seminar. Today one of the CFL’s newest grad students, Martin Perales, will talk about his summer project exploring the impacts of lake development on fish populations. 
Perales holds a striped bass, which is a n invasive saltwater species in the Sacramento-San Joaquin River Delta. Photo courtesy M. Perales.
Perales holds a striped bass, which is a non-native estuarine species in the Sacramento-San Joaquin River Delta. Photo: M. Young

Who are you, where are you from, and how did you get here?    
I’m Martin Perales and I dragged my wife to Wisconsin to attend the UW-Madison. (Editor’s note: Martin’s wife, Flora, willfully joined the Wisconsin adventure and, we think, is enjoying her time in Madison!)
Before moving here I received my bachelor’s degree from the University of California – Davis, and then worked as a research technician in Peter Moyle’s lab for a few years. We were looking at how hydrodynamics in the Sacramento-San Joaquin River Delta interplayed with water quality and how that affected fish populations and distributions.
The Delta is connected to the ocean and tidally influenced by it, which makes it a really hard system to study, because things like water quality and water-level stage and the availability of habitat are constantly changing. It was a cool place to work, but I came to Wisconsin because I just wanted to see something else. I’d been in California my whole life.
Pretend we just boarded an elevator and you only have one-minute to tell me about what it is you’re presenting on at seminar.  

Low water levels leave prime aquatic real estate, like these logs, stranded on shore. Photo: Jereme Gaeta
When they’re under water, logs like these provide “coarse woody debris,” or prime real estate for some fish species. Here they’re out of the water due to drought, but lakefront homeowners also often remove logs near shore. Photo: Jereme Gaeta

I’m going to spend my summer at Trout Lake Station researching how lakeshore residential development impacts fish populations in the Northwoods. We understand that, when people build homes and use the lakeshore, they impact different elements of habitat – things like what substrate is on the lake bottom, or the amount of fallen trees or aquatic plants in the nearshore habitat.
Why should someone not in the field of freshwater sciences care about your work? (The dreaded “So What?” question).  
When there are people living on a lake, in general, they reduce a lot of these habitat elements. They make the shoreline more homogenous, and trying to tie that to how it impacts fish has been elusive. Different species of fish have strong habitat associations, certain species live only in aquatic vegetation, or around submerged wood or they prefer a certain substrate. We may intuitively just assume that these changes negatively impact populations of fish we care about, but understanding how fish communities respond to changing these habitat combinations isn’t really well documented.
 Tell me about one funny, memorable, exciting or awesome moment from your work either in the field or in the lab.
Perales casts a net into the murky waters of a slough - presumably right before the boat got stuck on a mudflat! Photo courtesy M. Perales.
Perales casts a net into the murky waters of a slough – presumably right before the boat got stuck on a mudflat! Photo: M. Young.

When we were out in tidal areas of the delta, we would constantly run the boat up on mudflats. There w ere quite a few boat strandings. Half the time you’re on plane (meaning the boat was skimming across the surface of the water) and you’re zipping up the slough, and would look behind you and see that the prop was turning up mud. You’d have to slow down and come off plane and then strip down and get ready to jump in. I wore shorts under my pants, because I knew I was going in, so I’d jump out and push us off the mud flats so we could get back to the channel.
Also, in the 1990’s a migrating whale got off track and made it up into the slough we did our study in. That was before I was there, but it’s still pretty cool.
Where do you hope to go from here either with this work, or, literally, after your time at Hasler Lab?
I guess it sort of depends on how I do in grad school! (laughs). But if I find I’m good at writing and doing science, then I’ll try to stick around in academia. But, if not that, I’ll work for a non-profit or agency and stick around in the sciences and do aquatic ecology for sure.