Q & A: Windsor Aguirre
July 27, 2012
Windsor Aguirre, assistant professor in the Department of Biological Sciences, takes DePaul students on trips to western Ecuador and Alaska to study how fish in new environments evolve. They conduct field work and lab studies as part of a project he leads, the Aguirre Lab at DePaul.
In 2008, Aguirre and his collaborators collected six fish in Ecuador’s Santa Rosa River that they could not identify. Later they learned their findings were a new species of suckermouth armored catfish, a discovery that was described recently in the scholarly journal Zootaxa and publicized in National Geographic magazine. Officially named Cordylancistrus santarosensis, the fish may provide a missing link in tracing the suckermouth catfish’s evolution.
Q: What work is done at the Aguirre Lab?
The premise of the lab is to learn how organisms adapt to new environments. We spend three weeks to a month in the field collecting specimens, and then we spend the rest of the year analyzing. We’ve done a lot of work with fish that have gone from an ocean to a freshwater habitat or from streams to lakes. Part of our work is in Ecuador, where I lived for years; we’ll begin a major research push there this summer. We also study a fish called the threespine stickleback in Alaska, and we have a student who’s trying to start a local project in Chicago.
We analyze the specimens using morphometrics. That means we take pictures of specimens, digitize landmarks and look at changes in structure using mathematical methods. We also use molecular markers—markers that are indicators of population history or species history—and we sequence DNA.
Q: Why focus on fish?
If you’re interested in questions related to evolution, fish are a great group to study. There are more types of fish than there are types of mammals, amphibians, reptiles and birds combined. It’s also a question of ease. The species I tend to work with are small, so it’s easier logistically than if you’re studying elephants.
Q: How do you catch them?
In Ecuador, we used an electro-fishing backpack. This looks something like what an astronaut would use, and it produces electricity. Obviously, it isn’t a good idea for humans to interact with electricity and water, but the amount is small and we wear protective suits (rubber waders). The electric current knocks out the fish for a while, but it doesn’t damage or kill them. Then we collect the fish into a bucket.
With the stickleback, we use minnow traps. The fish enter a funnel and typically swim to the sides. Then they can’t get out. They’re stuck.
Q: How long do evolutionary changes take to occur?
It depends. The more we look, the more we realize that significant changes in characteristics can occur over a few generations. This is especially true when there is a new environment, such as when a river is dammed and forms a lake. The predators, the food, the availability of oxygen and the characteristics of the water all change. Suddenly this population that was probably pretty well-adapted to the river is in a different kind of environment. That will lead to evolution.
Q: How did you learn the suckermouth catfish you collected was a new species?
We didn’t realize this suckermouth catfish was a new species when we collected it—we didn’t know what it was. We had collected multiple species of this family, and I identified most of them to the best of my ability. Jon Armbruster, a taxonomist at Auburn University, is an expert on this group, so I e-mailed him photos. He confirmed that we correctly identified some of the fish we collected, but he wasn’t sure about a few others. One was this new species. Jon is from Chicago, and he stopped by the lab when he came home for Christmas. He looked at it under the microscope and said he didn’t know what it was—that it might be new. He took it to his lab for more analysis. In March, John and a graduate student published a journal article describing the new species, Cordylancistrus santarosensis.
Q: Is there a larger meaning to this finding?
One feature that distinguishes this species from other suckermouth catfish is the unusual plating on its head. It appears intermediate between fully plated and unplated groups in the family. Evolutionary biologists try to go back in time to figure out the history of all species on Earth, but huge gaps exist. When you find an intermediate species, it helps uncover the evolution of the traits. With the discovery of this species, scientists can learn more about the suckermouth catfish.
We’ve learned quite a bit about biology, but there’s still an enormous amount we don’t know. Humans develop land to exploit natural resources, which could lead to deterioration of rivers and forests. In many cases, we’re losing species before we know they exist. Western Ecuador isn’t that remote. We didn’t have to go hours and hours on a boat, and the area was close to some towns—yet we discovered a new species. The larger picture is: There’s still a lot we need to do.
Visit Newsline Online's photo gallery to see photos of Aguirre capturing fish in Ecuador and the new suckermouth catfish.