DECISION CLOSE ON MANAGING MENHADEN AS FORAGE

Every fish is part of an ecosystem, and plays a role in keeping its ecosystem intact.

There are predators and prey, specialists and generalists, aggressive hunters of smaller fish and those that subsist by filter feeding on plankton.

While all are different in their own way, in one respect, they’re all the same:  Removing any one of them from an ecosystem will have impacts on other ecosystem components.  And while that’s true of all species, it’s particularly true of the smaller “forage fish” that tie together the food web, feeding largely on plankton while being preyed upon by a host of larger fish, marine mammals, and seabirds.

Yet fisheries managers have largely ignored fishes’ ecological role when managing various species.  The only passing consideration that they gave it was to include “natural mortality,” or the rate at which a species might perish as a result of predation, ocean conditions, or other non-anthropogenic causes, in the calculations that lead to estimates of stock health and acceptable harvest levels.

But it always was harvest levels, whether acceptable or otherwise, that was at the heart of such calculations.  At best, the goal was maintaining fisheries that were sustainable in the long term, taking natural mortality into consideration.  What was rarely if ever considered was the impact of overall mortality, including both natural and fishing mortality, on the ability of a given species to perform its traditional role in the ecosystem, and support other populations that depended upon it, to a greater or lesser degree, for their own sustainability.

Now, there appears to be a good chance that, for the first time, the Atlantic States Marine Fisheries Commission will decide to manage Atlantic menhaden with so-called “ecological reference points” that, if adopted, will prioritize the species’ role in the food web when setting harvest levels. 

Instead of setting annual catch limits on a single-species basis, where the only concern is setting harvest levels low enough to assure that the fishery will remain sustainable in the long term, regardless of its impacts on the ecosystem, such catch limits might be calculated based not only on sustainable landings, but also on the need to leave enough menhaden in the water to allow the fish to fulfill their traditional role in the food web.

Of course, food webs represent the interlocking relationships between many species, both animal and plant, and it would be very difficult, and likely a practical impossibility, to accurately reflect all of those relationships in a mathematical model.  Fortunately, in order to properly manage Atlantic menhaden, such complexity isn’t required.

Scientists instead modeled the ecological role of the Atlantic menhaden with respect to four predators—striped bass, bluefish, weakfish, and spiny dogfish—as well as one other forage species, the Atlantic herring.  It turned out that even that much detail isn’t required.  As the Ecological Reference Point Work Group and Atlantic Menhaden Technical Committee recently reported in a memorandum to the ASMFC’s Atlantic Menhaden Management Board,

“Atlantic striped bass was the focal species for the example [ecological reference points] because it was the most sensitive predator fish species to Atlantic menhaden harvest in the…model, so an [ecological reference point] target and threshold that sustained striped bass would likely not cause additional declines for other predators in the model assuming no other major perturbations to the food web/ecosystem structure.”

The Atlantic Menhaden Management Board originally considered a motion to adopt ecological reference points at the ASMFC’s winter meeting, which was held last February.  However, some Management Board members wanted additional information, including what the reference points might look like at various levels of bluefish, weakfish, spiny dogfish, and Atlantic herring abundance.  As a result of their request for additional information, the vote on the motion was postponed until May.

Unfortunately, by the time that May came around, the COVID-19 pandemic had come around, too.  As a result, the ASMFC was forced to hold its May meeting as a webinar, and as it was doing so for the first time, it decided to limit the number of action items on the agenda, and postpone what it could until its August meeting, when it would have a better idea of how webinars function and how best to hold such a meeting.  The issue of adopting ecological reference points for Atlantic menhaden was one of the deferred items.

But it now appears that the issue will receive an up or down vote when the Management Board meets on the afternoon of August 5.

Again, the meeting will be held as a webinar, but the May meeting proved to the ASMFC that webinars work, and so the Commission now feels comfortable addressing complex management issues such as ecological reference points in such a setting.

When the postponed motion comes up for a vote, the Management Board will hopefully move forward, to include ecological reference points in the Atlantic menhaden management plan.  If they do so, a decade-long effort by conservation groups and some angling organizations will be on the verge of success.

There are compelling reasons to adopt such reference points.  As Wild Oceans, a conservation group that has been a key player in the ecological reference point debate since it began, noted in a recent release,

“menhaden are critical forage for a wide diversity of marine life in the Atlantic, including many commercially and recreationally-valuable fish like striped bass, bluefish, tuna, cod, king mackerel and tarpon, as well as many species of seabirds and marine mammals…[T]he ecological reference points are based on the best available science from the Ecological Reference Points Assessment that the [Atlantic Menhaden Management] Board approved for management use in February.  [internal formatting omitted]”

Wild Oceans wisely wants to see menhaden managed to the ecological reference point target, and asks anyone commenting on the issue to

“Insist that the ASMFC adopt the new [ecological reference points] with the clear intent of managing to the [ecological reference point] TARGET.  Maintaining abundance in the water is the goal for a forage species, not simply preventing the collapse of menhaden and its predators (managing to the threshold).”

Wild Oceans is right on every count.  It has also joined with the Conservation Law Foundation, National Audubon Society and the Pew Charitable Trusts to prepare joint comments for the Management Board, which say, in part,

“We urge you to adopt the [Ecosystem Reference Point] Work Group-recommended and peer-reviewed [ecosystem reference point] target of 0.19 and threshold of 0.57.  We also encourage you to commit on the record and to the public that the Board intends to conservatively manage to this new target reference point, defined as the maximum fishing mortality rate (F) on Atlantic menhaden that sustains striped bass at their biomass target when striped bass are fished at their F target.  As striped bass and other menhaden predators, as well as numerous prey species, along the Atlantic coast continue to struggle, managing to the new, more protective [ecological reference point] target becomes key.  Doing so will not only serve to encourage recovery of these species, but can also buffer the negative impacts of swings in menhaden population abundance and recruitment at a time when the ecosystem is rapidly changing.  It will have the added benefit of bolstering forage availability for predators that also rely on depleted prey like Atlantic herring…particularly in New England where older fish return if the population is healthy and hopefully in the South Atlantic where a recovery has not yet happened.”

Again, it all makes sense. 

The problem is that managing menhaden with ecological reference points could, at some point, require harvest to be cut.

That’s not the case today, when the actual fishing mortality is slightly lower than the ecological reference point target.  But should menhaden abundance decline, maintaining a fishing mortality rate at or below the ecological reference point target could require a harvest reduction, and there are people out there who could very well be opposed to that.

And those people, and their allies on the Management Board, could very well oppose the adoption of ecological reference points for just that reason, knowing that traditional, single-species management will allow them a larger kill, even if the stock declines.

Thus, it would make sense for anyone concerned about conservation-oriented menhaden management to send comments in to the ASMFC prior to 5:00 PM on July 28, which is the last day for comments to be included in the supplemental materials, although comments received prior to 10:00 AM on July 31 will still be printed and electronically distributed to all Management Board members.

All comments should be emailed to comments@asmfc.org, and the ASMFC notes that the comments should clearly include the commenter's desires about distribution—that is, “include in supplemental materials” or “distribute to Management Board.”  Also, the “subject” line of the email should clearly indicate that the email addresses “Atlantic Menhaden ecological reference points.”

It only takes a few minutes to compose an adequate email, that will let managers know that you would like to see menhaden managed for their ecosystem role, and not merely for their value as bait or as fish meal.  Helping to convince them that is the case will pay dividends in the number of striped bass, bluefish and other species that we’ll be able to catch in the future.