The Mysterious Case Of Alaska’s Crabs

SHAHLA FARZAN: This is Science Friday. I’m Shahla Farzan.

JOHN DANKOSKY: And I’m John Dankosky. And now it’s time to check in on the state of science.

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JOHN DANKOSKY: Local science stories of national significance. Alaska has announced that two upcoming crab fishing seasons will be canceled. For the first time, snow crabs will not be fished in the Bering Sea. Neither will red king crabs, for the second year in a row. The reason for this cancellation? Well, the populations of these crabs have plummeted, and scientists are trying to find out why.

So where do they go? Joining me to talk about this is someone who’s been covering this story. Kirsten Dobroth is news director and reporter at KMXT Public Radio in Kodiak, Alaska Kirsten, welcome to Science Friday.

KIRSTEN DOBROTH: Thanks for having me.

JOHN DANKOSKY: Let’s start with a headline first. It reads, “1 Billion Crabs Have Gone Missing.” So first of all, how do we know it’s 1 billion?

KIRSTEN DOBROTH: Well, if you can believe it, it’s actually a lot more than 1 billion. The total population estimate for snow crabs in 2018 was 11.7 billion animals. And last year, when the survey was done to estimate how much of that population was still around, it was 940 million crabs. So that’s more than 10 billion crabs in about three years that have gone missing.

JOHN DANKOSKY: When we see a headline that says, “the crabs have gone missing,” the question is, are they missing, or do we just have a lot fewer crabs? I mean, explain exactly what we’re talking about here, to the best of our knowledge.

KIRSTEN DOBROTH: Well, they can’t really say definitively what happened to the crabs. The best estimate is that this was climate-driven changes in the ocean that led to the population collapse. And they can’t see what’s happening on the bottom of the ocean. But the best guess that they have is that they died. And they don’t really have answers right now beyond what the theories are as far as the causes for that.

JOHN DANKOSKY: So this must be an enormous deal economically for your part of the world. Explain a little bit how big the economic impact might be.

KIRSTEN DOBROTH: It’s huge. Commercial fishing directly employs about 60,000 people in Alaska. And that doesn’t include supporting jobs. It contributes billions of dollars to Alaska’s economy. And Bering Sea snow crab is a pretty lucrative fishery, one of the most lucrative fisheries in Alaska. On top of that, coastal communities collect taxes off of seafood landed at their ports. So that’s millions of dollars in taxable revenue.

On top of skippers that are going to be missing out, a deckhand alone can make $50,000 to $80,000 in a season going out for snow crab. So these are people that are not going to be working this year. Those boats are tied up, and it costs money not to fish. Those people who own boats, they are going to have to be paying for insurance, boat payments, you know, upkeep and maintenance on their boats. So this is a really big deal that has a lot of ripple effects. And that snow crab fishery alone is worth about $200 million in Alaska’s economy.

JOHN DANKOSKY: Wow. So then, what are you hearing from the fishermen?

KIRSTEN DOBROTH: I spoke to a fisherman here in Kodiak the day after the closure was announced, Gabriel Prout. He’s a multigenerational crab fisherman. He was still kind of reeling from the news. But this is what he had to say about learning about the closure.

GABRIEL PROUT: People are really going to have to make some hard calls here, whether that’s selling out completely of their quota shares, selling their vessels, looking for other opportunities in other fishing sectors, which are few and far between. Fishermen are really going to be hurting the next year.

KIRSTEN DOBROTH: The Bristol Bay red king crab, which is the other fishery that’s closed– that had been on the decline, and they had been anticipating that that fishery would close again. But to see such a precipitous collapse in the snow crab population has just been really hard for people to fathom. They’re going to have to make some pretty hard decisions, not just Gabriel Prout and his family, but a lot of fishermen.

JOHN DANKOSKY: Is this being thought of as just a really bad season, or is this something different?

KIRSTEN DOBROTH: Well, I think it speaks to what I’ve heard from a lot of fishermen, researchers, and biologists in the last year. And that goes to the variability of the ocean right now and the changing ocean conditions from climate change. Just in the last year, 14 of these federal fisheries disasters were approved by the US Secretary of Commerce for fishery collapses that happened between the years 2018 and 2021, with most of those disasters coming in 2020.

So we’re seeing a lot of variability and vulnerability in Alaskan fisheries. You know, this goes beyond just Bering Sea snow crab fishermen, even though this is a very big one. This is something that fishermen across the state are paying attention to.

JOHN DANKOSKY: So near where I live, over the years, the lobster fishery has changed because of warming water temperatures. Lobsters like to survive in a very specific, narrow band of temperatures. Is there something similar happening here? Is climate change changing the water temperatures in such a way that scientists think it might be affecting the crabs?

KIRSTEN DOBROTH: Yeah, that’s exactly it. So basically, snow crabs love sea ice. And in the winter, traditionally, there’s this covering of sea ice in the Bering Sea. And in the summer, that sea ice melts, and it creates what’s called the cold pool. So it creates this dense cold water that sinks to the bottom of the ocean floor and provides really critical habitat for snow crab.

In 2018 and 2019, in particular, these warmer water temperatures were observed in the Bering Sea. And researchers, for the first time, saw almost no sea ice almost all the way up to the Bering Strait. So that was the year that there was also, if you keep in mind, this record number of snow crabs that were seen, was 2018. And then, over the course of the two years that the water warmed up, the cold pool was much smaller.

And one of the theories is that because this cold pool wasn’t present, particularly in the summer, it allowed more predators to get at the snow crabs. It allowed for– these snow crabs were probably pushed into a smaller area with less habitat and less food. They could have just starved because they didn’t have that critical habitat to foster their growth.

JOHN DANKOSKY: So what happens next?

KIRSTEN DOBROTH: Well, that’s the big question. You know, I’ve heard from a lot of people that there’s a need for more research to better understand this. But I’ve also spoken to researchers who point to the fact that climate scientists have been saying we’re going to see this type of variability in the oceans for decades. So I think that there’s a few different levels to this. And one is, how do we connect fishermen, researchers, and policymakers and make sure there’s a clear line of communication between them? How do we engage social scientists to prepare coastal communities and fishermen about the decisions they’re going to have to make and the variabilities they’ll see in the ocean?

And then, from this very real financial aspect that these fishermen are dealing with, how do we find better ways to support our fishermen when they need it? How do we provide fast relief as the ocean is changing? And I know it’s not really satisfying, but I don’t think there’s a clear answer on that right now. And nobody that I’ve spoken to has had one, either.

JOHN DANKOSKY: Kirsten Dobroth is news director and a reporter at KMXT Public Radio in Kodiak, Alaska. Kirsten, thanks so much for bringing us this important story. I appreciate it.

KIRSTEN DOBROTH: Great to be here. Thanks.

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