Ulcerative skin disease can mean a devastating end for a fish. Scales get circular white patches, causing lesions and scale loss. Fins deteriorate. Fish become lethargic and swim sideways. Most are eaten before they die.
But what causes the condition? Marine heat waves created by El Niño weather patterns may be partly responsible, according to new research from students and professors in the UF/IFAS School of Forest, Fisheries, and Geomatics Sciences.
During the summer, marine sciences undergraduates Melanie Gomez, of the Orlando area, and Kamila Koralasbayev, of Bethesda Md., joined Robert Lamb, Ph.D., a research assistant professor with the UF/IFAS Nature Coast Biological Station, and traveled to the Galápagos Islands to study the environmental impacts on sea life.
“It was an incredible experience,” Gomez said. “We learned so much in such a fast amount of time — more than we could have in any year-long class.”
Lamb had encountered ulcerative skin disease while monitoring fish populations in the Galápagos as part of his doctoral thesis research. Along with his UF colleagues, he helped connect the 2014-2016 El Niño climate pattern to an outbreak of the disease, and the research team expected another outbreak during the 2023-2024 El Niño.
When photos revealed sick fish last year, the research team – including Donald Behringer, Ph.D., a professor of marine and disease ecology in the School of Forest, Fisheries, and Geomatics Sciences; Roy Yanong, V.M.D., a professor in the Tropical Aquaculture Laboratory and an extension veterinarian; Kuttichantran Subramaniam, Ph.D., a research associate professor in the College of Veterinary Medicine; and Felipe Pierezan, D.V.M., Ph.D., a clinical associate professor in the College of Veterinary Medicine – secured National Science Foundation grant for $200,000 to further the study.
Subsequent funding from UF’s College of Agricultural and Life Sciences allowed Gomez and Koralasbayev to travel to the Galápagos and participate in the research, too. They learned that El Niño events act as “natural laboratories” that “fast-forward” climate change years into the future by creating marine heat waves, Lamb said.
“Warmer water facilitates the metabolism of pathogens,” he said. “At the same time, it reduces the amount of food, and the fish have less to eat, so their immune systems become compromised.”
Gomez and Koralasbayev conducted underwater surveys to understand how populations of marine fish and invertebrates respond to variations in environmental conditions such as temperature.
At the Charles Darwin Research Station in Puerto Ayora, Ecuador, the students dissected hundreds of fish collected from ocean waters of different temperatures to learn how ocean warming affects metabolism and parasite loads. Isotope analysis of muscles and livers revealed what the fish ate and their position within the food web. Measurements of otoliths – inner ear bones responsible for sensing gravity and movement – revealed how much the fish grew.
Koralasbayev described the lab as a factory chain of researchers working in sync.
“We got to experience every single part of that chain, and that was super interesting to see and to get that hands-on experience,” she said. “You never get that in a class. When are you realistically going to have the time to spend hours and hours in a lab like that?”
Back at Lamb’s UF lab, Gomez and Koralasbayev are busy drying and pulverizing several thousand samples of fish tissue so that a mass spectrometer instrument can measure their atomic structure for food web analysis. Using the data they collect, the students will contribute to studies that will likely be published early next year.
Lamb praised Gomez and Koralasbayev for their contributions to the project, which expedited the process.
“They were able to help us get really high-quality samples that we weren’t able to get in the past,” he said. “So this is not just a training exercise; they were really a vital component of this team.”
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The mission of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is to develop knowledge relevant to agricultural, human and natural resources and to make that knowledge available to sustain and enhance the quality of human life. With more than a dozen research facilities, 67 county Extension offices, and award-winning students and faculty in the UF College of Agricultural and Life Sciences, UF/IFAS brings science-based solutions to the state’s agricultural and natural resources industries, and all Florida residents.
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