by Karl Blankenship,

East Coast fishery managers have agreed to tie future menhaden population levels to the number needed to support a robust striped bass population — a first step toward recognizing the ecological role of the small bait fish.

The action, made by a unanimous vote, was described by conservation groups as “landmark” and “historic” because it was the first time the Atlantic States Marine Fisheries Commission has explicitly recognized the value of leaving fish uncaught to serve as food for predators.

The exact impact won’t be known until October, when the commission, which regulates migratory species in state waters, will set menhaden harvest levels for the coming year. Changes along the coast and in the Chesapeake Bay are not likely to be significant, because a pair of recent assessments found the menhaden stock to be robust.

But populations of menhaden and their predators fluctuate over time, and the commission’s action means its future decisions will take into account whether enough menhaden are available to support the fish, marine mammals and birds that feed on them.

“With managers committed to leaving enough menhaden in the ocean to provide forage for predators like striped bass and humpback whales, a new chapter now begins for ecosystems from Maine to Florida,” said Joseph Gordon, director for the Pew Charitable Trust’s campaign to protect marine life on the East Coast.

Controversy over menhaden management has simmered for years. Measured by their collective weight, the annual menhaden harvest is the largest of any species along the coast and in the Bay. Although the population is considered to be in good shape, conservation groups have long contended that such analyses don’t fully account for menhaden’s importance as a food source for everything from dolphins to osprey.

The new “ecological reference points” essentially set a goal of maintaining menhaden at levels adequate to support a robust striped bass population. That was based on computer modeling that showed striped bass were the species most sensitive to menhaden abundance.

Over time, as new and better information becomes available about interactions among species, the action clears the way to manage the abundance of menhaden — and potentially other “forage” fish — to help achieve and maintain population goals set for other species.

Conversely, if many predators become abundant at the same time, managers may eventually need to consider curbing their numbers to allow for a sustainable population of menhaden, Atlantic herring and other fish that serve as their food.

Omega Protein, which operates a menhaden fishing fleet out of Reedville, VA, and is by far the largest harvester of the fish in the Bay and along the coast, issued a statement endorsing the commission’s decision. But it also emphasized that managing interactions between predators and prey is not a one-way street and must expand the focus beyond menhaden.

“It is now the responsibility of the commission to accurately estimate the populations of both menhaden and its predators and then make fair and equitable management decisions based upon the model’s findings,” the company said.

Indeed, establishing the right amount of menhaden to protect from harvest could be challenging and a source of future debate. For instance, menhaden are currently relatively abundant, but striped bass numbers are low. One commission member wondered about the purpose of leaving “excess” menhaden in the water to support a striped bass population that doesn’t exist.

Matt Cieri, a scientist with the Maine Department of Marine Resources who chaired the commission’s ecosystem reference point workgroup, acknowledged the action will place a new level of complexity on management decisions.

But, he added, the ecosystem approach will help ensure that menhaden abundance does not hinder other efforts, such as new catch restrictions, aimed at rebuilding the striped bass population. “It is sort of a chicken and egg argument,” Cieri said. “You may not have the striped bass to consume the menhaden, but if you don’t have the menhaden then you won’t have the striped bass to rebuild.”

Cieri and others cautioned that simply ensuring more menhaden are left in the water will not by itself restore species that are at low levels and overfished.

“This is not the cure-all for all fisheries management problems,” said Spud Woodward, chair of the commission’s Menhaden Management Board. “[But] it is a step in the right direction.”

The commission is expected to take the next step this fall when it begins translating the new policy into a catch limit.

“I don’t think anyone is expecting a huge management change as the result” of the new ecological reference points, said Chris Moore, an ecosystem scientist with the Chesapeake Bay Foundation.

And because the new policy addresses menhaden coastwide, not regionally, it likely will not immediately affect Bay catches, which are already subject to their own harvest cap. But leaving more of the fish uncaught, Moore said, could mean more menhaden in the Bay, which is an important nursery area.

“I hope there is a biological response and that we end up with more in the Chesapeake,” Moore said.