HPU research explores pathways of marine toxins affecting Hawaiʻi’s reef fish

Hawaiʻi Pacific University undergraduate students and faculty researchers are contributing to important new research aimed at reducing incidents of ciguatera poisoning, a serious, underreported illness caused by eating reef fish and invertebrates contaminated with naturally occurring marine toxins.

Leading the way is university Associate Professor of Marine Science Matthew Iacchei, Ph.D., who serves as the principal investigator, in collaboration with HPU chemistry Professor F. David Horgen, Ph.D. They worked closely with five undergraduates at the university. 

The team’s research project is housed in HPU’s Downtown Science Laboratories. There, spring 2025 valedictory speaker and HPU graduate Valentina Salgado Montanez and HPU student Kaylee Tanig gained valuable, hands-on experience this spring studying a microscopic marine organism that can pose serious health risks to humans.

Salgado Montanez plans to pursue graduate studies after completing internships in Asia this summer and has participated in the field collections. She and Tanig, a second-year marine biology undergraduate student, are leading the toxin analysis in the laboratory.

“We’re trying to understand what drives the presence of these toxins in the environment,” Iacchei said, noting that fish are an important local food source. “Can we get an idea of the dynamics of the organisms that produce the toxins and how the fish are interacting with them, so we can possibly create a monitoring system? If we can do that, we’ll be better positioned to alert communities when the risk is elevated.” 

The HPU team is primarily focused on Gambierdiscus spp., a genus of toxic dinoflagellate species that live on algae (limu) in Hawaiʻi’s nearshore waters. When herbivorous reef fish consume the algae, the toxins accumulate in their flesh, sometimes at dangerously high levels, and continue to magnify up the food chain. Humans who consume the contaminated fish can experience a range of symptoms, from nausea and neurological effects to chronic fatigue that can last for months.

“There’s no taste, no smell, and no way to cook the toxin out,” Horgen said. “And we expect the problem may worsen as ocean temperatures rise and the distribution of  the toxic organisms expand.”

Ciguatera poisoning is most prevalent in reef predators, but has also been recently detected in reef herbivores, including fish commonly caught and consumed in Hawaiʻi. These fish include: uku (green jobfish), ulua/papio (giant trevally), mu (bigeye emperor), kole/palani (surgeonfish), ʻomilu (jacks), kaku (barracuda), roi (grouper), and knifejaws. 

With support from a $50,000 grant from the IDeA Networks of Biomedical Research Excellence, HPU’s team is collecting samples from coastal areas on Oʻahu.

“I am very grateful for this experience,” Tanig said. “Working hands-on with sophisticated tools and lab equipment this early in my academic journey has given me a real head start. I’m learning techniques now that many students don’t encounter until graduate school.”

Leading the field work for this research are Kelsie Kuniyoshi and Justin Chan from the University of Hawai‘i at Mānoa, along with HPU alumnus Mylou Matur. Matur has been leading the laboratory microscope counts, working along with HPU spring 2025 graduate Veronika Pearson, HPU graduate student Klara Sobotikova, and HPU undergraduate Leila Tewahade, who is entering her senior year this fall. 

The students’ work has already reached scientific audiences. Salgado Montanez and Tanig presented their research at both the IDeA Networks of Biomedical Research symposium and HPU’s University Capstone presentations this spring. Pearson and Matur shared their findings at the American Fisheries Society’s inaugural Pacific Islands Chapter Conference, held on April 30-May 1. They were joined by Kuniyoshi, who was the collaborator supporting the research fieldwork.

HPU’s research is part of a larger collaborative effort involving other organizations in Hawaiʻi such as the Nalley Lab at the University of Hawaiʻi at Mānoa, the University of Hawaiʻi Sea Grant College Program, National Oceanic and Atmospheric Administration’s Pacific Islands Ocean Observing System, Mālama Maunalua, and others. The project also aligns closely with the HPU’s mission to provide undergraduates with early, meaningful access to research opportunities that are often not available at the undergraduate level.

“Our undergrads are doing the work of graduate students by the time they earn their degrees at HPU,” Horgen said. “They’re learning to troubleshoot, think critically, and make real scientific contributions. They have gone on to earn doctoral degrees from some of the most prestigious universities across the country.”

Looking ahead, the team hopes to secure additional funding to expand their work, including the possibility of developing a rapid test to detect the toxin in fish tissue, and to possibly establish a research center focused on marine toxins and community health.

“We want to reduce the incidents of ciguatoxin poisoning in humans going forward,” Iacchei said, “and to recognize that there may be more frequent incidents in the future due to global climate change.”

To learn more about undergraduate and graduate programs in the College of Natural and Computational Sciences, click here.