College of Science

Walsh receives $100K grant to fund student's fish research

Matt Walsh, an assistant professor of biology, has received a $100,000, two-year grant from Luminant Energy which will fund a study of how heated thermal effluent from power plants influences the evolution of a common species of fish.

The grant, which was awarded through Luminant’s Environmental Research Program, will support research by Amanda Boyles, a second-year master’s student in Walsh’s lab. Boyles will conduct experiments on Gambusia affinis, or western mosquitofish, near the Big Brown Power Plant outside Fairfield, about 100 miles southeast of Arlington.

The western mosquitofish was selected because it is the most widespread freshwater fish in the world and because it lives near the surface, where it feeds on zooplankton, small insects and insect larvae - mosquito larvae in particular. From the 1920s to 1970s, the fish was introduced to lakes and rivers around the world due to its reported effectiveness in controlling mosquito populations. While it is credited with helping to contain malaria in South America, Russia and the Ukraine in the 1920s, it is a voracious, aggressive predator which has wiped out many native species and is extremely difficult to eradicate.

“This study has the potential to add to our knowledge of how changes in environmental factors can affect a species’ development,” Walsh said.

Boyles’ experiments will involve a population of G. affinis residing in the main reservoir of Lake Fairfield, and a population of G. affinis exposed to thermal effluent discharged by the power plant in the “hot pond” which adjoins the plant. The experiments to be conducted include phenotypic trait assays and two sets of reciprocal transplant experiments.

The first experiment, which will run for 12 months, will address what the phenotypic correlates of heated thermal effluent in Lake Fairfield are, and how seasonality influences these potential differences.

“Phenotypic trait assays will be conducted, which will consist of collecting gravid (pregnant) female G. affinis monthly over the course of a year in order to assess differences in reproductive investment between the hot pond and main reservoir populations,” Boyles said. “Offspring size, clutch size, and wet and dry weight of both females and offspring will be quantified between the hot pond and main reservoir populations. This also will determine how seasonality influences these differences, if at all.”

The second experiment will address whether or not heated thermal effluents drive life history evolution in G. affinis.

“This question will be addressed by conducting two sets of reciprocal transplant experiments; one in the lab and one in the field,” Boyles said. “These experiments will quantify any differences in growth rate and reproductive allotment between the two populations and will isolate genetic influences from environmental influences, if there are any. During these experiments, all fish will be weighed and measured for a full month and any

Matt Walsh watches as Amanda Boyles dissects a mosquitofish in Walsh’s lab.
gravid females will be dissected afterwards to quantify reproductive allotment.”

Boyles, who earned a B.S. in Biology from UT Arlington in 2012, said the experiments should be completed by May 2015, followed by at least six months of writing her thesis. Boyles said that Robert McMahon, professor emeritus in biology, made her aware of the Luminant program and also about previous research on G. affinis by Robert H. Britton.

“I am hoping my results will illustrate how thermal effluent can influence the evolution of life history traits of G. affinis,” Boyles said. “More generally, these results could represent an important step in the integration of evolutionary biology and conservation science.”

Boyles credits Walsh and professor emeritus in biology Robert McMahon with making her aware of the opportunity with the Luminant program and with helping her formulate the experiments. She says she eventually would like to work in fisheries conservation with the U.S. Fish and Wildlife Service or with a state or local fish and wildlife agency.

For more than 40 years, the Luminant Environmental Research Program has supported students working on graduate degrees from Texas institutions who are interested in pursuing research on the environmental effects of surface coal mining, power generation and electric transmission lines. Luminant finances the research but has no review, editing or publishing rights.

To ensure objectivity, an autonomous steering committee of scientists, educators and advisers guides the program. Independent from Luminant, this uncompensated group approves research topics, awards fellowships and supports students and professors in publishing the results. The 10-member committee includes two UT Arlington faculty members: Jonathan Campbell, professor and chair of the biology department, and Melanie Sattler, an assistant professor of civil engineering. The program has provided over $4 million in funding for the completion of 100 independent, published student theses and dissertations.

Posted April 14, 2014