What warming waters could mean for Maine’s fishing economy

Fishing is a major part of Maine’s economy, with commercial fisheries generating about $709 million in 2024, according to state data. But what happens when a warming climate begins to collide with business?

Scientists consider the Gulf of Maine to be one of the fastest-warming ocean regions in the world — and changing conditions have already reshaped parts of the industry.

In Maine, warming waters have contributed to long-term declines in northern shrimp populations. Shrimp fisheries in the Gulf of Maine have been closed for more than a decade, after regulators imposed a moratorium on shrimping — a ban that has now been extended until 2028.

And it’s not just shrimp.

Graham Sherwood, a senior scientist at the Gulf of Maine Research Institute, says warming waters could begin to affect Maine’s billion-dollar lobster industry, even as the fishery remains strong today.

Marketplace’s Sabri Ben-Achour spoke with Sherwood. The following is an edited transcript of their conversation.

Sabri Ben-Achour: So we're a decade into this moratorium on shrimping. What does the fishing industry in Maine look like today?

Graham Sherwood: The fishing industry in Maine looks like lobsters. There's some ground fishing, no shrimping, but lobsters is kind of where it's at.

Ben-Achour: What is lobster fishing like, given changing climate?

Sherwood: So we've seen a rise in lobster landings over the last couple decades, and it actually hit a maximum in 2016 and that could be related somewhat to warming, actually, it increased some of their productivity. What we've seen over the last 10 years or so is a little bit of coming back from that, and it might seem like it's getting too warm for lobsters. But I should mention the lobsters are still a highly valuable fishery in the United States.

Ben-Achour: Do you think shrimp fishing will ever realistically return to Maine waters? I mean, this moratorium goes till 2028 now.

Sherwood: I do not. We have seen this warming trend sort of persisting over the last couple decades. Now, certainly there's a lot of variability, but if we look at the long term trend, we're actually seeing the Gulf of Maine warming faster than most areas of the globe. So there's no reason to expect that trend to come back anytime soon.

Ben-Achour: Zooming out, looking kind of generally, at the different species that we rely on commercially or can rely on commercially, which ones are doing better, which ones are doing worse, as the climate changes?

Sherwood: We're starting to see indications that it might be warming too much for lobsters, although lobsters, as an industry, is still doing very well. The history of the Gulf of Maine is sort of centered around a lot of ground fish species like Atlantic cod. Cod is more or less feeling the same kind of effects of warming as the shrimp, and we've seen their populations decline to historically low levels.

We're also seeing some bright spots in terms of recovery. There's been a lot of habitat restoration efforts, mostly to remove dams and rivers, and what that has led to is a resurgence of river herring — particularly a species known as alewife, which is a silvery fish that's food for many other species in the ocean. Any kind of silvery fish in the Gulf of Maine is potential bait fish for the lobster industry and so there is potential economic value in that.

And also, I should mention that the Gulf of Maine is warming quite fast, but there are areas in the Gulf of Maine that are still remaining relatively cold, and could support these cold-water fisheries, such as Atlantic cod. And so if we could actually match up where those fish are going to basically avoid the warm waters and then also have access to food such as alewife, that could actually be a win-win situation.