Once more those small, silvery, nutrient-rich fish called menhaden have taken center stage in fisheries management and Chesapeake conservation. On May 5, the Atlantic States Marine Fisheries Commission (ASMFC), which manages the coast-wide catch of menhaden and 23 other migratory fish species, met in Alexandria, Va., to revisit the way menhaden are managed. Specifically they met to discuss raising the harvest quota for menhaden after a recent stock assessment found an increase in biomass (the total weight of the population), but a decrease in abundance (the actual number of fish).
Often dubbed "the most important fish in the sea," menhaden are a fundamental link in the Bay's food web, serving as valuable sustenance for striped bass and many other fish, marine mammal, and seabird species. Their health directly affects the health of the entire ecosystem.
We sat down with Bill Goldsborough, CBF's Fisheries Director, to get a better understanding of what happened at the meeting, and what it means for the fate of this critical fish.
- What happened at the meeting earlier this month?
The Atlantic States Marine Fisheries Commission voted to increase the current cap on menhaden harvest by 10 percent for both 2015 and 2016. It was a good management decision, because stakeholders on both sides seemed to be satisfied, but it was not a great conservation decision. CBF had urged ASMFC not to increase harvest quotas until measures were taken to ensure menhaden's ecological role in the Bay and beyond was protected.
That said, a really good thing for menhaden conservation came out of this meeting. ASMFC initiated the process to amend the management plan for menhaden. With the amended plan, they are once and for all committing to developing ecological reference points (guidelines for optimal population levels and allowable fishing rates). The reference points we have right now are based on single-species management, designed to only account for the health and survival of menhaden alone, not the ecosystem as a whole. They do not fully account for menhaden's ecological value as an important forage fish that other marine creatures depend upon for food. Ecological reference points will effectively be more conservative guidelines for the fishery that will leave more menhaden in the water for the striped bass, osprey, and all the rest of the species in the ecosystem that depend on menhaden. This is huge . . . we've never had this level of commitment to develop and adopt ecological reference points.
- How did ASMFC come to this decision?
Five years ago, a menhaden stock assessment found that we had a depleted stock of menhaden, and there had been a history of overfishing. This spurred ASMFC to establish a catch quota (the first time ever in the history of menhaden management) and to set it at a level 20 percent below recent harvests, beginning in 2013.
Now we have a new assessment that's just come out. It's good science and much more comprehensive, but it includes some different assumptions. One in particular assumes there is a mass of larger, older menhaden in northern waters off the coast of New England that are outside the range of the fishery (large menhaden that are not often caught in the fishery but that have been seen in surveys done by northern states). The menhaden fishery is concentrated in the mid-Atlantic, especially in and around Chesapeake Bay. The net effect of these large, old menhaden is to increase the biomass estimate over what we thought from the last assessment.
- So menhaden that reside outside the area where people actually fish are boosting the biomass number?
Exactly. To me, the most insidious thing that I don't think we're paying enough attention to is that as a result of this finding of increased biomass, the fishing industry is saying that we can catch more fish, but a lot of the fish are outside the area where fishing occurs. We're increasing the catch in the area where we don't have that higher biomass. And, according to this latest assessment, in an area where there is actually a lower abundance of menhaden—fewer numbers of fish in the population. In fact, it's the lowest abundance in the 60-year history of assessing the menhaden population, according to this new model. So the assessment does show higher biomass, but it also shows low abundance. The way to think of it is there are relatively more big, old fish, but not a lot of fish total. And numbers of prey are what's important to predators like striped bass. So this is a dynamic that we have to come to grips with.
- What's next for menhaden?
We have to stay on top of the process that will play out through 2016. The amended management plan won't take effect until the 2017 fishing season. This is going to be a long, methodical process. We want to get it right this time.
- Why are menhaden so important?
Menhaden are the fuel of the food web, and we control the flow. Too low and we have problems with striped bass nutrition, diseases, mortality, and so forth. For a predator like striped bass that depends a lot on menhaden, if they're not a lot of menhaden available, they will shift to something else that's probably not as nutritious. They might shift to blue crabs—is that better for the bigger picture? So it's a tradeoff between management objectives. You have to think in an ecosystem-sense rather than a single-species context for ecologically important fish like menhaden. One industry representative calling for a catch increase at a recent ASMFC meeting said, "Don't leave these fish in the water to die!" That short-sighted statement ignores the fact that leaving menhaden in the water to be eaten satisfies an important management objective to keep the ecosystem healthy. You get incredible value from leaving these fish in the water.
For the sake of the striped bass and the osprey, the bluefish and the bald eagle that rely on these small, but all-important fish, we are pleased that ASMFC will be taking the long view and considering the health of the broader ecosystem when amending the menhaden management plan. After all, a healthy menhaden population means a healthier Chesapeake Bay.
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