IU student research contributes to invasive species management
Aug. 16, 2016
For most, a trip to the Caribbean means a week of sand and sun. But for recent IU graduate Ben Grubbs and his advisor, School of Public and Environmental Affairs adjunct professor Stephen "Chip" Glaholt, it meant tackling the region’s most invasive marine pest: lionfish.
In June, Grubbs traveled to Council on International Educational Exchange Research Station in Bonaire through SPEA, a study abroad program led by Glaholt. Their summer research was an extension of the work they began, along with IU junior Haley Erickson, on their spring 2016 trip to the same research facility. During the spring trip, they tested a novel technique to dramatically improve the way lionfish are managed in order to reduce the species' destructive effects on coral reefs.
“Lionfish are voracious predators and will eat any fish that can fit into their mouths,” Glaholt said. “Their insatiable appetites have decimated fish populations that are essential for keeping coral reefs healthy. This in turn harms both the reefs themselves and the livelihood of the fishermen and local communities who depend on them.”
Currently, the most effective management strategy to prevent the spread of lionfish is to catch each fish one by one using spear-like tools, or spear guns. This type of culling practice is only effective in recently invaded areas where lionfish numbers are still low. However, detecting lionfish is more difficult in low-density areas. Thus, a technique that would allow managers to detect lionfish without having to see them would greatly improve their ability to stop the spread of this destructive invader, Glaholt said.
Grubbs and Erickson, under Glaholt's direction, applied classroom teachings and their own research experience surrounding environmental DNA, or eDNA, to create a more effective process to detect lionfish. By analyzing water samples for traces of lionfish DNA, they were able to confirm not only the presence of the fish species but also hoped to determine the population count in a specific area.
Previous research scientists have used the amount of eDNA present in a specific water sample to estimate the number of organisms. But by creating a way to find a unique genetic sequence that would indicate the presence of more than one individual fish, Glaholt's team hopes to identify early signs of an invasion and help managers identify key areas to focus their attention.
“Last summer I worked as a field and laboratory technician for Dr. David Lodge at the University of Notre Dame on his eDNA research,” said Erickson, a native of South Bend, Ind. “I became really interested in eDNA because it possesses a lot of potential for invasive and endangered species management. Seeing as how my major is environmental management, I was really interested in the application of eDNA research to management practices, and because I would be responsible for a lot of the researching and writing that happened for our experiment, allowing me to gain more experience.”
The group’s spring break trip was a whirlwind of learning by doing, both in the lab and in the field. For lab experiments, they set up aquariums containing varying numbers of lionfish and used it to test the presence of lionfish DNA and the ability of the novel method to correctly determine the number of lionfish in each tank. They completed field experience to verify that the lionfish could be detected with this method in the ocean. For the entire week they were in Bonaire over spring break, they were spending every day either setting up equipment, testing water samples or snorkeling to find lionfish in their natural habitats.
“I obtained experience in basic lab techniques that I was not exposed to prior to this experience, developed a deeper understanding about all the components that go into a research project and improved my ability to write scientific papers,” Erickson said. “This project was a good way for me to really figure out if this area of environmental management is something I'd be interested in pursuing into the professional level.”
When Grubbs and Glaholt traveled back to Bonaire this summer, they expanded their eDNA research to include shark tracking.
“I learned a lot about the ecology of Bonaire and what the locals are doing in regards to conservation on the island," Grubbs said. "It was a great experience, and I met a lot of great people.”
"This research could not have been done without the financial support of IU’s Hutton Honors College, SPEA and CIEE, as well as the logistical support and expertise of Dr. Peachey’s group at CIEE-Bonaire," Glaholt said.
Once summer concludes and their research is complete, they plan to publish their work in hopes of contributing to the management of the lionfish species and prevent further destruction to marine life.