April 2012 – With your help, our work to conserve menhaden—a fish critical to the Chesapeake and Atlantic coastal ecosystems—continues.
The process for increasing protections for this important fish is now in phase two. Last fall in phase one, the Atlantic States Marine Fisheries Commission (ASMFC) adopted new standards for managing the menhaden fishery that will require cutbacks in the catch in an attempt to more than triple menhaden numbers coastwide. Phase two involves drafting a new fishery management plan laying out how to achieve the new standards. Next fall in phase three, the ASMFC will formally adopt the new plan, which will describe the catch restrictions that will take effect in 2013.
Once the subject of a book entitled, The Most Important Fish in the Sea, menhaden play a key role in the Chesapeake and Atlantic coastal ecosystems. Much like oysters, they feed by filtering the water and removing plankton which are often overabundant in polluted estuarine waters. Somehow the menhaden converts this input into biomass rich in omega-3 oils which makes them in turn highly nutritious prey for a wide range of marine fish, birds, and mammals.
Striped bass, for example, normally feed heavily on menhaden, but the amount in their diet has gone down dramatically as menhaden numbers declined over the last 20 years. Lack of menhaden in their diet may be a primary reason why Chesapeake stripers suffer from the disease Mycobacteriosis. Similarly, ospreys' success in finding menhaden to feed their young has gone down sharply in recent decades, and the survival of nestlings in the lower Bay is now less than during the DDT era.
New scientific advice in 2010 drove ASMFC to act after 10 years of slow progress protecting menhaden. The science indicated that numbers of menhaden population had been overfished in 32 out of the previous 54 years and was at its lowest level on record. The ability of the coastwide population to reproduce was only 8 percent of what it had once been. Even a panel of independent scientists advised that this was too low and called on ASMFC to better protect the stock and increase the spawning potential.
Read the full story at the Chesapeake Bay Foundation.
Analysis: The Chesapeake Bay Foundations states, "menhaden population had been overfished in 32 out of the previous 54 years and was at its lowest level on record." However, as the most recent stock assessments from the Atlantic States Marine Fisheries Commission (ASMFC) show, overfishing has only occurred once in the last 10 years, and the menhaden population is currently not overfished. Environmental factors, rather than commercial fishing, are also much more likely to influence the size of the menhaden population, with the ASMFC concluding that "non-fishery sources" are likely responsible for fluctuations in population (pg. 91).
The CBF also writes, "much like oysters, they feed by filtering the water and removing plankton which are often overabundant in polluted estuarine waters." The results of several recent studies have cast doubt on this claim. These studies have shown that adult menhaden do not consume most kinds of phytoplankton, and instead consume mostly zooplankton. And while juvenile menhaden do consume phytoplankton, they do not do so at a rate that contributes to improving water quality in a significant way.
Finally, the CBF writes, "lack of menhaden in [striped bass] diet may be a primary reason why Chesapeake stripers suffer from the disease Mycobacteriosis." There is no widely agreed upon answer for what causes mycobacteriosis in striped bass. However, the answer is just as likely to be the result of environmental factors in the Bay as a result of dead zones. These dead zones, caused by algal blooms fueled by excess nutrient runoff in the Bay, create low-oxygen (hypoxic) areas in the water that bass usually inhabit. They are forced instead into warmer, shallower waters for which they are ill-suited. As a result of the thermal stress this causes, the bass are not able to feed properly, making them more susceptible to diseases.