In Hawai’i, Conservation Has Also Provided Fishermen Economic Benefits
Papahānaumokuākea Marine National Monument, along the northwestern Hawaiian islands, has been under some kind of conservation protection since the days of Theodore Roosevelt’s presidency. It is a deeply sacred place to native Hawaiians. And at more than 583,000 square miles, it’s also the world’s largest fully protected no-fishing zone, after its expansion under the Obama administration in 2016.
Marine protected areas like Papahānaumokuākea are designed to provide refuge to fish and other marine mammals that have been overexploited and otherwise threatened by human activities. But research has remained inconclusive on if these protections provide enough benefits to nearby areas to blunt the economic impact of exclusion zones. This is especially debated in the case of big, mobile, migratory species like Hawai’i’s all-important bigeye and yellowfin tuna.
Now, new research from an interdisciplinary team of economists and ecologists looked at how well Hawaiian tuna fishermen did when they fished close to the monument, and further away. And they found, to their surprise, that there was a strong benefit, which increased in the years after the monument’s expansion. Fishermen near the monument caught more tuna, for the same amount of effort, than fishermen further away.
Co-host Shahla Farzan talks to first author Sarah Medoff about the surprising findings, and why the economics of a marine protected area might matter to conservation decisions.
Invest in quality science journalism by making a donation to Science Friday.
Dr. Sarah Medoff is a researcher in the School of Ocean and Earth Science and Technology at the University of Hawai’i-Manoa in Honolulu, Hawai’i.
SHAHLA FARZAN: We’re going to leave Alaska and head south, and we’re fishing for a good news story. We’re visiting the waters around the northwestern Hawaiian Islands, the Papahanaumokuakea Marine National Monument. It’s a pristine stretch of ocean and islands that’s been under conservation protections of some kind since 1909.
JOHN DANKOSKY: So there’s no fishing at all allowed there. I feel like that would kind of be a nice place to be if I were a tuna.
SHAHLA FARZAN: Yeah, that’s the hope. These marine protected areas are established to try to give fish and other marine life a safe place to breed, grow, and recover from the stress of us trying to eat them.
JOHN DANKOSKY: But it’s been hard to tell if that protection will eventually come back to benefit the local fishermen who are agreeing to stay outside those boundaries. That is, will people catch more tuna outside the refuge just because the refuge is there? Scientifically, this is called spillover.
SHAHLA FARZAN: Dr. Sarah Medoff is a fisheries economist and researcher at the School of Ocean and Earth Science and Technology. That’s at the University of Hawaii in Manoa. And she’s part of a research team that’s found that, at least with this particular marine protected area, the answer seems to be a resounding yes. Sarah, welcome to the show.
SARAH MEDOFF: Thank you. I’m happy to be here.
SHAHLA FARZAN: First, can you introduce us to the Papahanaumokuakea Marine National Monument in Hawaii? What makes it so special?
SARAH MEDOFF: Yeah, this is a marine protected area that is surrounding the northwest Hawaiian Islands. In 2016, it was expanded, making it the world’s largest contiguous marine reserve, or no-fishing zone, in the world. The size of the area is, I think, roughly about three to four times bigger than the state of California.
SHAHLA FARZAN: And this area is also culturally important to Native Hawaiians. As someone who’s lived in Hawaii your whole life, how would you describe that cultural significance?
SARAH MEDOFF: Yeah, so in Hawaii, the culture here on the islands is very connected to all the natural resources that the islands provide. And so that area is very culturally significant to the Native Hawaiians just because it has all of these resources encompassed in the boundaries. I think on the island, we prioritize conservation efforts of our native species pretty heavily just because they are so vulnerable to extinction or overextraction or overharvest.
SHAHLA FARZAN: Why tuna in particular and not some other fish species? Like, I’m sure we’re talking about more than just fancy sushi here, right?
SARAH MEDOFF: Yes. It’s funny you should ask that. Originally, this project– we weren’t originally going to focus on tuna specifically. When we started this project, we kind of shared that common perspective as everybody else that no-fishing zones would only benefit smaller, less mobile species like coral or like lobster and that, really, there wasn’t going to be a no-fishing zone large enough to really offer any benefits for larger, more mobile species like tuna.
And so the original idea for this project was to really look at the Papahanaumokuakea and see if it was going to provide any benefits to smaller fish, and maybe we would see some sort of relationship with species mobility and spillover benefits. And so when I had written the code and ran our models and conducted our analysis, and I went to go view the results, and there was, in fact, a positive spillover effect for yellowfin and bigeye tuna, we were kind of in a state of shock because it was results that were really surprising, we were not expecting. And that’s when we really realized that we might really have something here. And that’s when we started to focus in on yellowfin and bigeye tuna.
SHAHLA FARZAN: Could you give us some numbers there? What kind of increases were you seeing for these different tuna species?
SARAH MEDOFF: So it was actually pretty large. The magnitude of the spillover benefits was largest for yellowfin tuna. We show that there was a 54% increase in catch per unit effort when fishing efforts were placed near the monument borders or the MPA borders as opposed to further away after the monument or the MPA was expanded. Bigeye tuna increased about 12%, and I think all species caught on an aggregate level increased about 8%.
SHAHLA FARZAN: For those of you who just joined us, I’m Shahla Farzan. And this is Science Friday from WNYC Studios, talking to Dr. Sarah Medoff about how a marine protected area in Hawaii seems to be economically benefiting commercial fishermen. Why would a no-fishing zone lead to more fish outside of the protected area? Like, does this tell us that tuna populations are maybe recovering from past overfishing?
SARAH MEDOFF: We’re not really clear what the mechanism is. I think that would require more data on inside of the marine protected area boundaries. But we have two ideas of what could be potentially driving these results. So the first is a growth and reproduction effect. So it could be that inside of Papahanaumokuakea boundaries, tuna species are using these areas as spawning grounds.
Another idea is just this local aggregation effect, in which case, maybe it’s possible that inside of the MPA boundaries, they are providing a safe refuge for species that tuna feed off of, or prey species, and in which case, those populations are rebounding and growing. As bigeye and yellowfin pass through those waters, and they see a large amount of food supply within a certain area, they might gravitate to that area. And that’s kind of causing this local aggregation effect, and in which case, as they start swimming past the MPA boundaries, they’re literally spilling over the borders and onto fishermen’s and captains’ hooks.
SHAHLA FARZAN: OK, so it sounds like there’s kind of a couple different possibilities here, like either the protected area is boosting tuna populations by giving them a safe place to breed, but it might also just be that tuna are drawn to that area, and they’re kind of using it as a safe haven, then.
SARAH MEDOFF: Yes, exactly.
SHAHLA FARZAN: Do you think it matters that the fishing industry is benefiting from us protecting the fish? Or is it just more important that we’re protecting them period?
SARAH MEDOFF: I think it’s important that we are balancing both conservation while still supporting the livelihoods of people who depend on this resource. With a project like this or with a conservation effort like this where we can get conservation and economic viability to both kind of align and work in unison rather than being viewed as two opposing forces that we have to sacrifice one for the other is probably the most optimal outcome.
SHAHLA FARZAN: Yeah. We’re often told by policymakers and other folks that there’s this choice we have to make between economic prosperity and protecting the environment. And this seems like an example where we don’t necessarily have to choose, where we could maybe have both. Do you think that’s accurate?
SARAH MEDOFF: Yeah, I definitely think so. I think this is what was so exciting about this project and why I personally was really excited to be a part of it, was because it is this perfect example where conservation and economic profitability can kind of align and work in unison. And I think it’s a nice sign that our conservation efforts are actually working. And it kind of gives me hope that if we construct a well-thought-out conservation plan, we can reverse environmental damages.
SHAHLA FARZAN: You know, obviously, you looked at this one protected area. But how generalizable do you think that these results are? Can we look at your data and say, OK, great, let’s put marine protected areas everywhere, and fishing is going to benefit?
SARAH MEDOFF: I think the biggest lesson I had taken personally out of this was that these marine protected areas need to be well designed. So the location matters. The size matters. The fact that Papahanaumokuakea is in this horizontal– spanning horizontally across the globe matters. And so I hope that this project sparks those discussions.
But for future MPAs and no-fishing zones, we do have to recognize that these do impose an initial cost. And we have to make sure that our investments are going to pay off in the future. And so I think the main takeaway is to make sure that these conservation efforts are well thought out and strategically planned.
SHAHLA FARZAN: Thank you so much for joining me today to talk about your research. This is so interesting, and it gives me a little bit of hope about the world.
SARAH MEDOFF: Yeah, thank you. I’m glad I’m on the show, and I’m happy to share it.
SHAHLA FARZAN: Dr. Sarah Medoff is a researcher at the School of Ocean and Earth Science and Technology at the University of Hawaii in Manoa.