Sunday, November 13, 2016
MENHADEN AT A CROSSROADS
Fishermen are a conservative sort, and fisheries management reflects that.
For many years, management tended to follow a single model, in which each species was assessed and managed in a vacuum, without thought to its relationship to any other species in the sea. Yes, predation was considered, but only as it impacted current mortality of the fish in question; there was no thought of what predation could be, or perhaps more importantly, should be, if a given species was abundant enough to fulfill its role in the food web.
Instead, species have been managed in a manner that considers sustainability in only its most basic form, in which two basic concepts determine annual catch limits: 1) How many fish may be removed from the population each year without causing a decline in abundance, and 2) Is the stock large enough to provide the highest sustainable level of landings each year?
That’s fine if the only consideration is keeping a species available and abundant enough to maximize future exploitation. It’s probably a perfectly good measure for managing high trophic level species such as sharks, billfish and tuna which, once fully grown, are only occasionally preyed upon by other species, and even works pretty well for somewhat smaller fish such as striped bass, bluefish, cod and king mackerel which, in the overall order of things, are much more often predator than prey.
But when you start getting into smaller fish, such as Atlantic mackerel and Atlantic herring, the utility of that sort of management starts to break down, because those species are small enough, and abundant enough, that they serve as typical forage for a host of larger fish.
When managing fish that are important forage for other species, mere sustainability isn’t enough; such fish must be managed for abundance, to assure that the predators that they support have an adequate forage base.
If that is true for mackerel and herring, it is particularly true of Atlantic menhaden, arguably the most important forage species on the entire Atlantic coast.
The debate over menhaden management has been very long and hard. I first got involved with the species in the late 1990s, and I know staff and volunteers at the Coastal Conservation Association who had been working on it for a few years before then.
Back in the ‘90s, menhaden were managed as an industrial commodity.
The Atlantic States Marine Fisheries Commission normally manages each fish stock by means of a species-specific management board that included representatives of each state interested in the species in question, and supports such management board with a species-specific technical committee made up of state scientists and advisory panel that represented every interested state.
However, prior to 2001, menhaden were effectively managed by the same industry that was responsible for most of the landings. The management board was not made up of representatives of all of the interested states, but instead of five state representatives, five industry representatives, the National Marine Fisheries Service and a member of the National Fish Meal and Oil Association.
Members of the Atlantic Menhaden Advisory Committee, which served the same role as technical committees established for other species, were appointed by the management board, and also included representatives from the states, the industry, NMFS and the National Fish Meal and Oil Association.
The fox had free run of the henhouse.
Thanks to the hard work of a number of angling and conservation organizations, that system was finally overthrown in 2001, when Amendment 1 to the Interstate Fishery Management Plan for Atlantic Menhaden established a management board and support structure that was consistent with those used for other species.
Since then, ASMFC’s menhaden managers have been spending their time trying to get a better understanding of the health of the stock and the factors that can drive down menhaden abundance. The most recent benchmark stock assessment passed peer review nearly two years ago, and found that menhaden were neither overfished for subject to overfishing.
However, those findings were based on a traditional, single-species approach to management. Now, ASMFC is seriously thinking about breaking new ground, and managing menhaden in a way that recognizes their role as a keystone species in the coastal ecosystem.
In possible furtherance of that goal, ASMFC has released the Public Information Document For Amendment 3 to the Interstate Fishery Management Plan For Atlantic Menhaden.
That document addresses a number of issues important to the future of menhaden management. However, it’s easy to argue that the question of managing menhaden as an important forage species, rather than managing it merely for sustainable harvest, is the most important issue of all.
As noted in the Public Information Document,
“Given the crucial ecological role that menhaden play as forage fish, the [Management] Board has expressed interest in developing ecological reference points (ERPs) to manage the menhaden stock. Menhaden serve an important role in the marine ecosystem as they convert phytoplankton into protein and in turn provide a food source to a variety of species including larger fish (e.g., weakfish, striped bass, bluefish, cod), birds (e.g., bald eagles, osprey), and marine mammals (e.g., humpback whales, bottlenose dolphin). As a result, changes in the abundance of menhaden may have implications for the marine ecosystem. ERPs provide a method to assess the status of menhaden not only with regard to their own sustainability, but also with regard to their interactions with predators and the status of other prey species…”
The Management Board asked ASMFC’s Biological and Ecological Reference Point Workgroup to develop ecological reference points for menhaden. Four different models have been identified which might be used to develop such reference points. However, because the models are very complex, such ecological reference points will not be developed and sent out to peer review until 2019.
Such reference points would be specific to menhaden. However, there are also other reference points that have been developed for more generalized use across forage fish species.
Such alternative approaches to forage fish management were described in a report entitled Little Fish, Big Impact, which was released by the Lenfest Forage Fish Task Force.
One suggestion is to restrict harvest enough to maintain forage fish abundance at a level no less than 75% of the abundance of an unfished stock. Another, somewhat less conservative approach would tie fishing mortality to natural mortality, and set the fishing mortality target at one-half of the natural mortality rate (Ftarget=0.29). Under such scenario, fishing would be halted at any time that abundance dropped below 40% of the abundance of an unfished stock.
Some biologists, including ASMFC’s Biological and Ecological Reference Point Workgroup, has questioned whether such guidelines are appropriate for menhaden. The Lenfest task force has argued that they are.
However, the big decision that ASMFC will have to make with respect to Amendment 3 is whether any kind of ecological reference points, including those eventually developed by the ASMFC Workgroup, should ever be used to manage menhaden, or whether traditional, single-species management should continue to be employed.
Reason dictates that traditional management measures, which emphasize sustainable harvest rather than a species’ role in the food web, are inappropriate for a forage fish as important as menhaden. As ASMFC noted in the Public Information Document, “changes in the abundance of menhaden may have implications for the marine ecosystem.”
Thus, menhaden must be managed with more than mere harvest in mind.
It is important that conservation advocates, along with fishermen who just want to be sure that there are enough menhaden around to assure an abundance of striped bass and other popular recreational species, tell ASMFC that they want to see ecological reference points adopted.
It would also be worthwhile to instruct ASMFC to adopt one of the generic forage fish guidance recommendations in the interim, until menhaden-specific ecological reference points can be developed. (To put one of those generic recommendations in context, in 2013, the last year considered by the benchmark stock assessment, fishing mortality was 0.22, already below the recommended Ftarget=0.29 of the guidelines, while abundance, measured in terms of fecundity, or the number of eggs produced, was a little over 50% of that of an unfished stock, above the recommended cutoff level of 40%. Thus, adopting such interim guideline would not unduly disrupt the current fishery before menhaden-specific reference points can be developed.)
The earlier people get involved in the fishery management process, the easier it is to put good management measures in place.
A number of angling and conservation groups have worked hard to get menhaden management to the point where it is today. Now, with the Public Information Document just released, is the perfect time for a broader group of people to get involved with the process.
ASMFC will be holding hearings on the Public Information Document in most coastal states at some time between late November and the middle of December. A schedule of such hearings can be found at http://www.asmfc.org/uploads/file//58237047pr38MenhadenPIDHearings_rev.pdf.
Anyone who wishes to read the Public Information Document in its entirety can find it at http://www.asmfc.org/uploads/file//5818f1a1AtlMenhadenAmend3PID_PublicComment.pdf.
Given how important menhaden are to our coastal fish stocks, people should make a special effort to turn out for one of the scheduled hearings and support the use of ecological reference points in menhaden management. Anyone who can’t make a hearing should send in written comments, to the address provided in the Public Information Document.
The adoption of ecological reference points would be a watershed not just for menhaden management, but for fisheries management as a whole. It would be sad to see the opportunity slip by just because folks didn't make the effort to provide needed comments.