Thursday, December 10, 2015
IT'S NOT JUST MENHADEN THAT MATTER
For the past few years, we have seen conservationists and fisheries managers begin to place new emphasis on maintaining healthy forage fish stocks.
Author Bruce Franklin dubbed menhaden “The Most Important Fish in the Sea,” while conservation and angling organizations banded together a decade ago in a group called “Menhaden Matters,” to urge the Atlantic States Marine Fisheries Commission to recognize the importance of the species as forage when it crafts management measures.
There’s no question that menhaden are a very important forage species. However, a new report focusing on the Chesapeake Bay suggests that many other prey animals may be as or more important to the maintenance of healthy recreational and commercial fisheries.
That report is an outgrowth of the Chesapeake Bay Multispecies Monitoring and Assessment Program, and encapsulates the results of twelve years of sampling the stomach contents of five major predators resident in Chesapeake Bay—the striped bass, summer flounder, Atlantic croaker, clearnose skate and white perch.
Survey results aren’t applicable everywhere—a different choice of predators would almost certainly have resulted in different prey species appearing in the samples, while samples taken off a rocky, high-energy coastline would not have contained many life forms common in the relatively sheltered Chesapeake waters. However, they do provide an example of how important it is to maintain an array of forage species.
The study denoted any forage species that comprised at least 5% of the stomach contents of no less than two different predators as “key”, while any species that comprised at least 5% of the stomach contents for a single predator was deemed “important.”
It turned out that of all the “key” species, it was the bay anchovy, and not the menhaden, which was the most-consumed animal in Chesapeake Bay. It comprised more than 5% of the stomach contents of four different species, while the menhaden only broke the 5% threshold in the stomachs of striped bass—and even there, bay anchovies, mysid shrimp and polychaete worms were more significant in the striper’s diet.
To give the menhaden its due, most of the striped bass sampled were relatively small; menhaden were a very important component of the stomach contents of larger striped bass, although such bigger bass are only in the bay for a short time. Menhaden are also important forage for other fish not included in the study and to various fish-eating birds. Thus, in a slight departure from study standards, they were also designated as a “key” forage stock.
However, it was some of the other forage species that should be drawing our attention. We may debate the quality of current menhaden management, but at least the Atlantic States Marine Fisheries Commission is giving it some attention, and taking the first halting steps toward incorporating its role as forage into management decisions.
Most of the other species listed as “key” or “important” items are not managed at all.
The Mid-Atlantic Fishery Management Council’s Unmanaged Forage Fish Amendment is contemplating extending protections to both bay anchovies (“key”) and Atlantic silversides (“important”), while the ASMFC extends protections to five other “important” forage fish, river herring, Atlantic shad and the immature stages of weakfish, Atlantic croaker and spot, in various interstate fishery management plans.
However, it is probably important to note that neither bay anchovy nor Atlantic silversides is likely to receive protection from the ASMFC at any time soon, even though if a fishery for such forage species is ever developed, it will probably be developed in inshore waters that fall outside the Mid-Atlantic Council’s jurisdiction.
Similarly, although the Mid-Atlantic Council has done some good work to reduce the bycatch of river herring and American shad, neither is subject to a real fishery management plan while in the ocean waters where they spend most of their lives, while the New England Fishery Management Council is backtracking on measures that it had already adopted to limit bycatch of such species in the Atlantic herring fishery.
Protection for forage fish species is spotty and incomplete, but protections for just about every other sort of forage—worms, mysids, mollusks and such—is generally non-existent, except at the most local level. And that’s a pretty big failure of resource management, given that seven of the twelve “key” forage species identified in the Chesapeake study were worms, clams and arthropods such as mysid shrimp.
In the end, despite their importance, such non-fish forage species may be the most difficult forage to protect. For many, although certainly not all, forage fish species, threats such as excess harvest or loss of access to upstream spawning grounds are clearly identifiable. But the threats to the various invertebrate species are more subtle and likely more numerous.
Nitrogen loading in places such as Chesapeake Bay, Long Island Sound and various coastal lagoons can result in hypoxia, which in turn leads to “dead zones” where the oxygen becomes insufficient to support most forms of life. Fish can usually escape such hypoxic zones (although doing so may force them from cool, deeper waters into warm shallows that give rise to other threats), but clams, worms and many small crabs and shrimp lack the ability to quickly abandon such hostile areas. Most perish, impoverishing the ecosystem and making it less able to support life.
Other invertebrates suffer from shoreline development of marinas, hotels and housing, which destroy coastal marshes either directly, through draining and filling, or through the steady runoff of petroleum products, herbicides, pesticides and other pollutants.
Some, which have evolved to live in barrier systems constantly reshaped by wind and tide, find their waters perpetually degraded when the Army Corps of Engineers insists on pursuing sand-pumping projects that fill in new, storm-carved inlets which would have brought clean, oxygen-charged waters into stagnating back bays. Some are harmed when sediments from Corps dredging projects blanket the bottom with a suffocating coat of silt, either killing them directly or destroying the submerged vegetation on which they depend.
As anglers interested in healthy fisheries, which in turn depend on a healthy abundance of forage, it is our responsibility to protect the smaller life forms, whether fish, worms or something else, from the myriad adverse conditions that may be forced upon them.
Historically, anglers have been willing to turn out in numbers to protect their favorite predator species. Recently, they have also been turning out to protect high-visibility forage such as menhaden. But we have to do more, and protect the other, unsung animals that our stripers and weakfish, red drum and flounder, depend on to survive.
Because, sure, menhaden matter. But so do isopods and polychaete worms.