If the high seas were closed to fishing, populations of migratory species such as tuna, billfish and shark would increase significantly and that would help the coastal fishing industry to flourish, a Cal Poly assistant biology professor has advocated in a recent study.
Cal Poly assistant biology professor Crow White created a computer simulation to test the theory with co-author Christopher Costello, a UC Santa Barbara professor of environmental and resource economics.
Their study was published March 25 in the Public Library of Science Biology peer-reviewed journal.
This is very much a conversation starter, White said, noting that the United Nations is looking into the study. It will take more detailed analysis on the science side (to implement).
Costello and Whites research concludes that closing international waters to fishing could help rebuild stocks of migratory species, ultimately aiding coastal fishing worldwide when those fish swim within 200 nautical miles of shore, where a nation has exclusive fishing rights.
But local and national representatives from the commercial fishing industry vehemently disagree that closing international waters would help the fishing industry or necessarily increase fish stocks.
The financial losses around the world coupled with the absence of high-quality protein would kill people and destroy economies globally, said Jeremiah OBrien, a member of the Morro Bay Commercial Fishermens Organization. This is (worse) than high school work, and they do need to give these things serious thought.
Before implementation, United Nations countries would need to agree on the studys findings and a change in the United Nations Convention on the Law of the Sea doctrine would be necessary, White said, as well as cooperation and treaties with coastal nations that arent members of the United Nations.
The studys analysis projects that fishery profits in exclusive coastal zones would double, fish yields would increase by more than 30 percent, and fish populations would increase by 150 percent.
Currently, the high seas where fishing isnt restricted make up roughly 58 percent of the worlds ocean territory. The exclusive economic zones (EEZs) are divided among 150 sovereign nations and make up the remaining 42 percent of the ocean area under the United Nations Convention on the Law of the Sea.
Countries with EEZs have the ability to exclude foreign fleets and create their own fishery management policies.
White said the study was motivated by increasing the economic value of the high seas. But a national commercial fishing representative disputes the studys conclusion.
This looks to me like a professor publishing a paper to fund his research as opposed to anything serious, said Zeke Grader, executive director of the Pacific Coast Federation of Fishermens Associations southwest office. Its going for the sound bite and doesnt do anything to heighten public understanding. It leads to more confusion.
Grader acknowledged that certain protections are needed for fish species, but he said a blanket closure of the high seas is not the answer.
He believes more funding is needed for research to assess stocks of fish to come up with the best plans for protection that dont cut off huge portions of the ocean from fishing.
Grader also says it would be difficult to enforce a high seas closure and likely illegal fishing would persist.
White said that satellite images would help enforce fishing in the high seas.
On his 50-foot boat, the Aguero, OBrien catches fish including salmon, swordfish, shark and tuna off the Central Coast. He called the recent study ridiculous.
OBrien conducts some of his fishing activity in international waters and believes his business would be hurt by the ban, along with the livelihoods of other American fishermen.
This wont change anything whatsoever, and we cant shut ourselves off and curtail our business, OBrien said. There is still going to be demand for swordfish in restaurants. This could mean wed have to buy it from Chile or Peru instead of catching it ourselves.
Costello and Whites simulated model created several management scenarios that considered biological, geographic and socioeconomic factors.
They didnt use specific stock data, which White said is difficult to determine and would require extensive additional study for the purposes of the research.
Rather, their model cited changes based on numerous variables including EEZ sizes, fish travel ranges between EEZs, and degrees of fish site fidelity (how far fish travel during their lifetime).
Costello and White plan to continue researching how a potential high seas ban would impact specific nations, species and seafood consumers.
Fish populations have declined significantly over the past 60 years as a result of overfishing, according to the study.
White said that blue fin tuna are estimated to be down about a third of what they should be if the oceans were well-managed, while swordfish numbers have dropped but are improving. Sharks are more difficult to assess, but populations are less than pristine, he said.
Before any new United Nations legislation, detailed stock assessments and impacts on individual fisheries would need to be examined.
That will take time, White said. Other scientists need to throw their thoughts in the ring.
Countries such as China, Japan and Spain specialize in high-seas fishing and could be hurt by a closure more than other nations.
The study claims that fish in the high seas that traverse multiple EEZs are overexploited relative to those contained in a single EEZ.
For many pelagic, migratory stocks such as tuna, billfish, and shark, the size of the EEZs has been insufficient to incentivize sustainable fishing behavior, Costello and White wrote in the study.
Local recreational fisherman Jim Webb said he sees the potential for benefits in the idea of closing the high seas to fishing.
Webb, a member and past president of the Cambria Fishing Club, said that no financial incentive exists not to catch fish, so international fishermen will continue to bring in catches using sophisticated technology to track the stocks.
Webb and his fellow club members fish fresh and ocean waters, catching trout, perch and rockfish such as lingcod, cabezon and kelp rockfish.
High seas closures that lead to increases in pelagic fish populations might benefit local anglers targeting tuna and may help apex predators, like great white sharks, to repopulate their ecological niche, Webb said. Healthier oceans benefit all of us and would be a welcome trend.