While Rhode Island has spent decades and millions of dollars erecting fish ladders, removing dams, and cleaning up its rivers to shore up dwindling herring populations, it’s a different case when the fish are in the ocean.

River herring, both the blueback and alewife species found in Rhode Island, are diadromous fish, meaning they spawn in freshwater but live their adult lives in the ocean.

A foundational species, river herring sit at the bottom of the aquatic food chain, helping to feed larger animals like striped bass and osprey. In past generations, they swam up many New England rivers in the millions, providing a source of food and income for locals; herring are considered an important food in Narragansett culture.

Efforts to improve their spawning habitat have brought the fish back to environments they haven’t lived in since before the Industrial Revolution. However, experts and stakeholders who spoke with ecoRI News said that what’s happening to river herring when they’re in the ocean has a huge and potentially negative impact on their survival: bycatch.

Looking at the numbers

River herring populations have fluctuated dramatically for decades, according to data from the Rhode Island Department of Environmental Management (DEM), despite consistent efforts to improve fish passage.

The number of herring counted in Rhode Island’s rivers hit a 10-year high of more than 240,000 fish in 2020, but dropped the following year to fewer than 100,000.

The numbers remained low for the next couple of years, although preliminary 2025 data show that the population is rebounding. With early data from only two of the four rivers DEM monitors for fish passage, the 2025 count showed triple the number of fish compared to the previous year.

According to Patrick McGee, principal fisheries biologist at DEM, things that can affect herring population are complex, but bycatch – the unintentional catching and often discarding of non-target fish in gear like nets and lines – is definitely one of them.

John O’Brien, of The Nature Conservancy in Rhode Island, has worked for years improving freshwater habitat for herring.

“I think the problem is going to be out in the ocean,” he told ecoRI News.

Similar recent herring declines occurred in Connecticut rivers, according to Kevin Job, a fisheries biologist with the Connecticut Department of Energy and Environmental Protection (DEEP).

In Connecticut, DEEP had spent the previous years stocking river fish, and even before that — like in Rhode Island — spending millions of dollars to restore fish passages.

“We’re growing the available habitat like crazy. We’ve removed a lot of dams. We’ve got, you know, dozens and dozens of fishways across the state. We’re moving more fish than we’ve ever moved before.” Kevin Job

“We’ll do what we do, and the fish will come back,” he said he thought. “So when they didn’t, that’s when I kind of started getting a little bit more pessimistic, and starting to look at things that in the past, people had discussed, and one of those things was bycatch.”

A tale of two herrings

Out in the ocean, river herring mingle with other species, including Atlantic herring.

Longtime fisherman and Rhode Island Saltwater Anglers Association vice president Richard Hittinger said that he doesn’t really even think of the species as being separate because their fates are so entangled when both the river and Atlantic herring are out at sea.

But there is one major difference: There isn’t a commercial fishery for river herring in Rhode Island — there’s been a moratorium on catching the fish since the early 2000s — while Atlantic herring are still fished commercially.

Atlantic herring trawlers often sweep river herring into their nets.

Instead of being considered true bycatch, which would have to be discarded, the river herring are categorized as “incidental catch” and can be sold alongside Atlantic herring.

In a way, that designation is better than categorizing them as bycatch, Hittinger said, which would mean the fish, often killed while being scooped up by a net, are thrown back into the sea.

“We don’t like that either,” Hittinger said, but allowing the sale of river herring is “not encouraging [fishers] to reduce their bycatch.”

Hittinger believes that bycatch likely contributed to the low herring numbers Rhode Island and Connecticut have seen over the last few years, and said the 2025 rebound is probably the product of a recently imposed cap on the Atlantic herring.

According to Eric Reid, the former Rhode Island representative on the New England Fisheries Management Council, “Over the last few years the commercial quota for the Atlantic herring has been set so low that the fishery and associated bycatch is almost non-existent.”

Boats that would have been focusing on Atlantic herring have moved onto squid, a fishery that “has very little interaction with herring,” he wrote in an email to ecoRI News.

Job said the lower 2023 cap on Atlantic herring in waters off southern New England, combined with a simultaneous closure of the mackerel fishery, likely reduced bycatch — helping boost river herring numbers in Rhode Island and Connecticut runs last year.

Job cited a University of California, Santa Cruz, study that found that much of the bycatch from the Atlantic herring fishery consisted of river herring from southern New England.

“Our study suggests that mitigating bycatch on the southern New England fishing grounds may benefit recovery efforts for alewife and blueback herring genetic stocks that have experienced the greatest declines in spawning adult abundances,” the authors wrote.

Looking north

While southern New England has struggled with its river herring populations, runs are chock-full of the fish in Maine, and Job said there’s a lot southern New England could learn from that state.

 At the time of year when the river herring and Atlantic herring are mingling, the Atlantic herring fishing areas around Maine are closed.

Job said that time-area closures and increased monitoring (hiring people to examine catch once it’s landed to get a more accurate sense of what river herring bycatch looks like) could make a significant difference.

The downside to the area closures is that boats would have to delay going out or travel farther out to sea to fish during those time frames.

“I feel for the fishermen. I feel for those companies, but I also feel for all the residents, all of nature, you know, the many millions of people who should be able to go and utilize these things,” Job said. “It’s really not fair that I have to tell a person, ‘Hey, you can’t take those fish, and if you keep taking those fish, you’re going to get fined.’ We had people this year getting fined over $1,000 a person for taking these fish. But an industry can take and sell millions.”

Time-area closures have been suggested to the New England Fisheries Management Council (NEFMC), the body that oversees Atlantic herring stock, but any movement on that has paused.

“This work was paused, along with other projects at the April, 2025 council meeting as part of the ‘management flexibility measures,’” according to NEFMC spokesperson Alexander Dunn. “These measures were in response to recent cutbacks at [National Oceanic and Atmospheric Administration] Fisheries and added council workload coming from the (then) new administration.”

“It’s a complicated fishery. You could have a year a little better … and the following year might be worse.” Rich Hittinger

To some extent there will be fluctuations due to all sorts of reasons, but Hittinger believes implementing an approach like Maine’s could help.

The Atlantic herring industry has been allowed to collect millions of river fish over the last two decades, while people who would have caught herring for bait or to pickle have been banned from doing so, he said. “We’re not allowed to catch one.”

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