If you were to round up all of the menhaden swimming along the Atlantic coast and somehow put them on a scale, they’d weigh in at about 1.2 million metric tons.
To visualize that, imagine 220,000 Asian elephants stampeding along the coast — about five times more than exist in the world. For menhaden, though, that equates to tens of billions of tiny fish. This fall, fishery managers will tackle the question of whether that’s enough.
An update on the status of Atlantic menhaden released in August found the population robust. The current biomass, combining their number and weight, is the greatest that scientists have estimated in the last four years — and more than was seen anytime from 1992 through 2007.
Menhaden are not overfished, the report concluded — fewer than 200,000 metric tons were caught last year.
But critics, including some scientists and many conservation groups, say those figures only tell part of the story. Menhaden should not be looked at in isolation, they say, but as part of the broader marine ecosystem, where the small, oily fish is an important food for other fish, whales, sea birds and a host of other species.
“We’re probably not going to damage the menhaden stock all that much by continued heavy fishing. It seems to be in reasonably good shape,” said Ed Houde, a fisheries scientist with the University of Maryland Center for Environmental Science. “But what happens to the rest of the ecosystem? That’s the question mark.”
In November, the Atlantic States Marine Fisheries Commission, a panel of state fishery managers that regulates catches of migratory fish along the coast, will grapple with whether it should continue to manage menhaden as a single species — or begin considering its value to the ecosystem as well.
The debate over menhaden comes amid rising concern over all forage fish, those small species that provide a critical link in the aquatic food chain by converting plankton into food for larger predator fish, birds and mammals. Historically, forage species have received less attention — and protection from overfishing — than the larger predators, such as striped bass.
The 2014 Chesapeake Bay Watershed Agreement reflects that concern, calling for state and federal agencies to determine whether there are enough forage fish in the Bay to feed the growing populations of fish, osprey — even whales and dolphins — populating the estuary.
But the ASMFC experience with menhaden shows just how difficult the issue can be.
Conservationists and scientists have been urging the commission to consider the food value of menhaden for more than a decade. That’s when recreational anglers complained about “skinny” striped bass in the Chesapeake. They blamed the situation on too many menhaden being caught in fisheries, particularly Omega Protein’s large “reduction” fishery based in Reedville, VA, which processes the fish into animal feed and nutritional supplements.
Omega accounts for about three-quarters of the coastwide menhaden catch. The remainder is divided among smaller, but growing, operations that catch the fish primarily for use as bait.
Studies never established a link between menhaden abundance and striped bass health, but the heightened concern about the food role of menhaden, both in the Bay and along the coast, led the ASMFC to pledge that it would eventually take the ecosystem role of the fish into account.
Progress has been slow, but in recent years the commission established an ecological workgroup to collect data and build a computer model that can help fishery managers, for the first time, estimate not just safe harvest levels, but also how many menhaden should be left to feed hungry predators — and, alternatively, whether other forage species are available for predators.
“We’re not just looking at menhaden alone in a vacuum,” said Shanna Madsen, who coordinates the workgroup for the commission. She said the work could eventually be applied to other species as well. “Folks are all kind of trying to figure out how to really understand the trade-offs in all of our fisheries,” Madsen said. “What’s best for that fish species?’ ‘What’s best for our stakeholders?’ ‘What’s best for the other species that are in the water depending on those fish?’ ”
The workgroup’s recommendations are expected in 2019, and could be translated into management actions the next year.
But this fall, the commission is updating its menhaden management plan, which sets acceptable harvest guidelines, or “reference points.” In response to years of vocal concerns about menhaden, the commission — for the first time — is considering whether to adopt an “ecological reference point,” as opposed to a traditional one that simply looks at the health of a single stock.
The ASMFC has been taking comments on options that range from continuing to manage menhaden as a single species; awaiting recommendations from its ecological workgroup; or adopting one of several ecological reference points adapted from studies that offer general guidelines about how many forage fish should be left uncaught — guidelines that would likely result in lower menhaden catches.
“Menhaden is such an important fish, [ecological reference points are] something people have really wanted to see ASMFC move toward,” said Chris Moore, senior regional ecosystem scientist with the Chesapeake Bay Foundation.“It has been somewhat of a glacial pace getting there, but hopefully we can get it implemented quickly.”
Moore hopes that the commission’s action could improve the situation in the Chesapeake. Even as menhaden numbers have rebounded along the coast, surveys find continued poor reproduction in the Bay. About 70 percent of the menhaden stock stemmed from the Bay a few decades ago, while only 30 percent originate there now.
But some question the rush for action when the ASMFC’s own ecological workgroup is expected to wrap up its work, which more specifically addresses the menhaden situation, in two years.
“It’s going to be done in a couple of years,” said Ben Landry, spokesperson for Omega Protein. “These would be interim reference points at best.”
Industry representatives, and some managers, want to avoid a potential repeat of what they describe as the “whipsaw” changes in menhaden management and catch limits of recent years.
Harvests were slashed and the first coastwide catch limits imposed by the commission in December 2013 after a stock assessment showed menhaden were overfished. But when a new assessment was completed two years later, using new information and updated computer models, it found the stock to be in good shape, with no evidence of overfishing. That prompted the relaxation of the harvest limits.
Indeed, most agree that the fish has have generally been increasing along the East Coast, particularly in northern areas. People can now take whale-watching excursions in New York Harbor, where the mammals are feeding on abundant menhaden.
“It’s amazing the number of whales,” said Ellen Pikitch, executive director of the Institute for Ocean Conservation Science at Stony Brook University in New York. She said that “gigantic schools” of menhaden are now common around New York and New England, a situation she attributed at least in part to the catch restrictions imposed at the end of 2013.
Nonetheless, Pikitch thinks menhaden harvests should be cut further. She was a lead author of a 2012 report funded by the Lenfest Ocean Program that analyzed information about forage fish from around the world, combined it with computer modeling, and concluded that more protective management was warranted for forage species in general because of their ecosystem role.
One of the options being considered by the ASMFC — and preferred by many conservation groups — was drawn from the Lenfest report’s recommendations. If that option is adopted, menhaden still would not be considered overfished today, but current catch levels would be higher than recommended, likely spurring new harvest cuts.
“A species can look great under a single species approach, but it could be in really bad shape when you look at it in an ecosystem context,” Pikitch said.
But others question whether general guidelines for large ecosystems, like those in the Lenfest report, should be used to manage an individual species like menhaden.
While many tout menhaden as “the most important fish in the sea,” it is hardly the only forage species for predators. Anchovies, herrings and a variety of other small fish are available, as well as worms and other invertebrates.
Abundances of those species often vary widely from year to year because of weather and other factors unrelated to fishing. In addition, what predators eat often changes with age and size; it even changes based on where they live.
Rather than using generalized recommendations, the authors of a paper earlier this year in the journal Fisheries Research said harvest policies should be tailored to specific species and ecosystems.
Ray Hilborn, a marine biologist at the University of Washington and the lead author of the paper, said that with menhaden, the fishery usually harvests fish that are 2 years or older, while striped bass and many other predators generally consume smaller fish. “The abundance of the small menhaden is absolutely not affected by fishing, and yet that’s the dominant menhaden consumed by striped bass,” Hilborn said. If the goal of reduced fishing is to leave more for striped bass, he said, the restrictions are likely to have little impact.
Hilborn’s view is echoed by the ASMFC’s own ecological workgroup, which said in a memo to managers earlier this year that the ecosystem models used in the Lenfest report don’t take the age and size of fish into account and therefore “can overestimate the effect [that] fishing on forage fish [has] on predators.” Instead, it said, “ecosystem models should be built specific to the system of interest.”
Pikitch — and conservation advocates — say they don’t disagree that the more specific menhaden approach being developed by the commission’s workgroup would be preferable. But, they say, more generalized approaches like the one recommended by the Lenfest task force are useful as a stopgap measure, especially if the timetable for the commission’s new models falls behind schedule.
“We’re not saying use it forever. We’re saying take a step in the right direction,” Pikitch said. “When the ASMSC’s new models are ready, they can and should replace these interim approaches that we’ve recommended.”
Much of the sense of urgency — or lack thereof — stems from a difference in how “precautionary” fishery managers should be in the face of uncertainty.
Pikitch, citing the adage “a stitch in time saves nine,” said rapid action on menhaden is warranted to protect other species. While menhaden may be more abundant, so are some of their predators — like the whales in New York Harbor. Predators such as whales, dolphins and sharks are long-lived and produce few offspring, she noted.
“They don’t have the capacity to rebound quickly,” Pikitch said. “If they collapse because their food supply has collapsed, then the consequences can be much more damaging overall.”
A soon-to-be published paper by Andre Buchheister, of Humbolt State University, used a more detailed ecosystem modeling approach that focused specifically on the role of menhaden and found a particularly tight connection between their abundance and striped bass abundance. It also found a connection between menhaden abundance and sharks, marine mammals and fish-eating birds.
“It suggests that you would want to be pretty careful about how you fish menhaden,” said Houde, who was a co-author of the paper and a participant in the Lenfest task force.
On the other hand, Peter Himchak, a senior fisheries scientist with Omega, said data from the ASMFC’s technical committee that oversees menhaden shows that current fishing levels are already leaving large numbers of menhaden uncaught and that catches could be increased to 318,000 metric tons without posing a significant risk to the stock. “When you’re only fishing at 200,000 metric tons, I think you are at a very precautionary level,” he said.
Hilborn added that being precautionary means more than just looking at the ecosystem. Fishery managers also need to be precautionary about protecting jobs and food supplies, he said.
“If you think the most important things in the world are predators, then precautionary would always mean harvesting less,” Hilborn said. “But if you recognize that we’re trying to do two things — produce food and protect the environment — then precautionary doesn’t necessarily mean fishing less.”
If fisheries are overly protective, he argued, demand will be met through imports — in some cases from areas where environmental impacts will be greater. “There’s a real cost to this precaution.”
The ASMFC is getting ready for an impassioned debate. In an unusual move, it has set aside two full days to deal with the issue when it meets near Baltimore on Nov. 13–14.