‘Disentangling the effects of aggregation’
The western and central Pacific Ocean is home to more than half of the global population of tuna, and Tiffany Vidal Cunningham is tracking its progress.
Cunningham, who studied aquatic sciences with faculty member Brian Irwin, became adept at assessing fish populations during her time at Warnell. She now puts that knowledge to use in New Caledonia, a collection of islands in the South Pacific, working for The Pacific Community. The organization provides scientific and technical advice to member countries throughout the western and central Pacific, a region roughly spanning from Australia north to Japan, and from Indonesia to east of Hawaii. There, Cunningham focuses on catch rates of skipjack and yellowfin tuna by the commercial fishing industry.
What makes the work unique, she says, is their interface with the commercial fishing industry and using that data to evaluate trends in fish stocks. The majority of tuna in the western Pacific is caught via a method called purse seining—using a long wall of netting to encircle schools of tuna—and Cunningham works to understand catch rates and monitor the status of the populations.
“I’m in a new position funded through the Pacific E.U. Marine Partnership program focused on standardizing purse seine catch-per-unit effort in commercial fisheries,” she says. “Understanding catch rates from this particular fishery is important because it’s the dominant fishery sector for tuna in the Pacific, but we don’t use that information to inform stock assessments because of what we call hyperstability.”
Because the fishery targets schooling aggregations, she explains, the fishery catch rates might give an inaccurate picture of the overall population dynamics. The industry also uses fish aggregation devices in this portion of the Pacific, which also keeps catch rates high. “So, my job is to build models to disentangle the effects influencing catch rates,” she adds.
Overall, though, western and central Pacific tuna stocks are healthy, she says, which is a significant accomplishment and also underlines the importance of the work done by Cunningham and Pacific Community.
While she admits she hasn’t had a chance to get out on the water yet (“I’m mostly staring at my computer screen,” she says, laughing), Cunningham says skills she learned at Warnell are now put into use every day. “When I was at Warnell working with Brian, I was mostly focused on quantitative analyses, working on statistical analyses related to fish populations and the effects of climate change or environmental variability,” she says. “So, now I’m honing those statistical skills. Modeling and knowledge of statistical analyses helped me get this job.”