UCSB researchers predict fisheries’ impact on schooling fish
Ana Guerra, a UCSB doctoral candidate, studies industrial fishing’s impacts for her dissertation.
An anchovy pizza relies not just on the chef preparing it (and the eater’s taste buds) but also the habits of the fish.
Fisheries rely on anchovies and other species congregating in schools in order to economically catch fish.
In fact, catching a school in a large net is a lot easier than reeling them in one by one.
UCSB doctoral candidate Ana Sofia Guerra was interested in schooling fish for a long time before deciding to research it. She talked to Dr. Andrew Berdahl at the University of Washington, Dr. Albert Kao at the Santa Fe Institute and Dr. Douglas McCauley at UCSB.
The conversation launched a new project.
The team created a theoretical evolutionary model to predict whether industrial fishing practices will cause fish to evolve into a less social population.
“It’s important to note that our paper is a theoretical model, we show that this is something that could potentially happen, or perhaps is already happening,” Ms. Guerra said.
In the model, as humans capture schools, the fish become less likely to form large groups. She hopes the research can be assessed in the field.
“If we find that this change is indeed happening, that fish are less inclined to form large schools and instead form smaller and smaller schools, then that could be the end of those fisheries and the livelihoods that depend on them,” she said. “It would become inefficient and far too costly to continue the fishery.”
The catch of the day could be a lot more expensive as generations of fish become more isolated.
“Think about where your food comes from,” she said. “Ultimately, it comes down to how much effort and funds are directed towards better managing fisheries, and that comes down to where your vote is cast and which policies are supported and prioritized.”
She recommends looking at resources like the Monterey Bay Aquarium’s Seafood Watch guide.
“If you live by or near the coast, find out about fisheries in your area and if they’re a sustainable option,” she said. “If so, shop local. Maybe there’s a seafood market you can go to or a community-supported fishery subscription service.”
While the overall consequences are unknown, scientists can still predict a few effects of isolated fish. Animals like the humpback whale feed on schools — some almost exclusively.
“It’s a pretty amazing sight. These whales will surround a school of herring by blowing a bubble net around them and then lunging through the center of their makeshift net to capture the fish,” Ms. Guerra said. “But at the crux of this feeding strategy is that it relies on fish forming schools.”
And it’s not just whales.
“In the open ocean, some seabirds and predatory fish such as tuna also feed on schooling fish, so the disappearance of these schools would mean that a main source of food for a lot of wildlife would be gone,” she said.
The results of the problem would be hard to reverse.
“We don’t know if this is happening out there in the ocean, that fish are losing that tendency to form big schools due to industrial fishing practices, but our model shows that it could,” she said. “Unless we dedicate specific effort towards finding out if this is indeed happening, it will be difficult to detect through catch data.”
While the situation is hypothetical, Ms. Guerra and her co-researchers created a model to better predict fish behavior. It was published in the Sept. 30 publication of Proceedings of the Royal Society B: Biological Sciences.
Email: ahanshaw@newspress.com
