December 11, 2012 — The following is an excerpt from a transcript of the Pew Environment Group's video, "Help Save Menhaden: Quite Possibly the Most Important Fish in the Sea."
They’re small, they’re oily, they’re not much to look at. But the humble menhaden could be the most important fish in the sea. That’s because these little fish feed much of the other fish and wildlife in the ocean around them. Striped bass and bluefish; humpbacks and other whales and dolphins; ospreys and terns; even sharks: all these animals and more depend on menhaden for survival. These little fish scoop up plankton, turn it into protein and fat, and send that energy up through the ocean food chain. But we’re breaking that chain.
Unrestricted industrial fishing is taking a toll. Menhaden have plunged 90 percent from historic levels, which means that some ocean wildlife can’t find enough to eat. Take striped bass, for example. In the Chesapeake Bay, menhaden made up most of a stripers diet. Now they’re just a small proportion, and many bass show signs of malnutrition and disease. The industrial menhaden fleet uses spotter planes to find schools of menhaden and then scoop them up in large nets. There is no legal limit on how much they can catch at sea. Menhaden are churned into feed for poultry and livestock, cooked down for oil, even used in pet food.
Analysis: As part of its continuing campaign to impose new catch limits on Atlantic menhaden, the Pew Environment Group’s recent video, “Help Save Menhaden: Quite Possibly the Most Important Fish in the Sea,” is filled with half-truths and distortions regarding the state of the menhaden fishery. Rather than present a balanced portrayal of the fishery and the debate over fishery management, Pew uses selectively edited facts to push its preferred agenda.
The misrepresentations from Pew begin with the title of the video. While environmental groups like Pew make liberal use of the phrase “the most important fish in the sea” in their menhaden campaigns, the phrase does not actually come from any scientific designation. Rather, it is based on the title of Rutgers University English professor H. Bruce Franklin’s book on menhaden, The Most Important Fish in the Sea. The designation is based on the qualitative judgements of the author, and there is no scientific evidence to support the statement that any one fish in the Atlantic ecosystem is “the most important.”
More substantially, Pew’s claim that “menhaden have plunged 90 percent from historic levels” is an incomplete statistic, and does not take into account natural variations of menhaden recruitment. While environmental groups often cite variations on the claim that there has been a 90 percent decline in the menhaden population over the last 25 years, this ignores the fluctuations that have occurred over the full series of available menhaden data, where alternating cycles of highs and lows in the menhaden population can be observed.
Climate and environment are strong influences on menhaden recruitment (the number of menhaden that are born), and as a result menhaden biomass will fluctuate along with climatic conditions. In the late 1970s and early 1980s, favorable conditions led to especially strong recruitment and years of high biomass, reaching a relative high point in 1984 with 65 billion menhaden. In contrast, the late 1960s and the current fishery have seen less favorable conditions, and subsequently low recruitment, with biomass statistics from the late 1960s roughly comparable to current numbers. For example, in 1966, there were an estimated 12.7 billion menhaden: 40 years later, in 2006, biomass was estimated at 13.6 billion menhaden. Menhaden have previously shown the ability to rebound from these lows without Atlantic States Marine Fisheries Commission intervention.
The scientific agencies responsible for overseeing menhaden recognize this link. NOAA, on its Menhaden Fact Page, states, “menhaden recruitment appears to be independent of fishing mortality and spawning stock biomass, indicating environmental factors may be the defining factor in the production of good year classes.” The Atlantic States Marine Fisheries Commission (ASMFC) similarly concluded in its 2010 stock assessment that fluctuations in menhaden abundance may be “almost entirely driven by non-fishery sources.”
This is also supported by the fact that, according to the 2010 and 2012 menhaden stock assessments, menhaden is not considered to be overfished. This means that, according to current measures, the stock is producing enough eggs to sustain itself. If recruitment remains low while egg production is at its target, it is probable that the problem with the stock is not that there are too few spawners, but that there are too few menhaden being born.
Pew is also quick to blame the commercial fishery for health problems now prevalent in Chesapeake Bay striped bass, saying “menhaden made up most of a striper’s diet. Now they’re just a small proportion, and many bass show signs of malnutrition and disease.” The disease that is referenced in the article, a bacterial infection called mycobacteriosis, is widespread among striped bass, present in as many as 76 percent of the Bay’s bass population. But a 2009 study, conducted by Dr. David T. Gauthier and published in The Veterinary Journal, on all available research on mycobacteriosis in the Bay found that there is currently no consensus about the primary cause of the disease, and it is not clear which of several potential factors has the greatest influence.
Like many issues affecting the Chesapeake Bay, environmental conditions probably play a key role. Excess agricultural runoff entering the Bay contains large amounts of nitrogen and other nutrients. These nutrients cause algal blooms, the excessive growth of phytoplankton and algae. When these blooms die off, the process of decay consumes the oxygen in the surrounding water, creating hypoxic (low oxygen) areas. These areas are usually in the cooler water that bass inhabit during the summer months. But because hypoxic conditions make them uninhabitable, the bass instead migrate to shallower, warmer waters for which they are ill-suited. The sub-optimal temperature makes them unable to feed properly, and makes them more susceptible to diseases like mycobacteriosis. This theory was originally developed by Charles Coutant, formerly of the U.S. Fish and Wildlife Service, who published several articles first observing the same phenomenon in striped bass in the Chesapeake Bay during the late 1980s and early 1990s.
Finally, Pew overreaches when it says “menhaden need a coastwide catch limit and 50 percent cut in the catch to end overfishing, and they need it now.” While Pew has been pushing for this 50 percent cut, the steepest of several possible cuts being considered by the ASMFC, it is impossible to say whether such a drastic reduction in catch will even benefit the menhaden stock. Although the ASMFC is required to set catch limits this December, there is an absence of reliable data on the current state of the fishery. The most recent menhaden assessment, released in 2012, is regarded as severely flawed by the ASMFC’s Menhaden Technical Committee. Among other issues, the assessment overestimates fishing mortality and underestimates menhaden biomass. The Technical Committee decided the assessment was unfit for management advice, and the assessment itself concludes that the flaws “cast considerable doubt on the accuracy of the estimates from this update stock assessment.” As a result, the last reliable data on menhaden dates back to 2008.
Ultimately, these facts reveal a fishery that is in a much less dire state than Pew would have its audience believe. While Pew presents a narrative which assumes that its proposed reduction in harvest is necessary, it is more likely that a far less severe cut would be most appropriate and effective, and would be in the best interest of the fishery and all of its stakeholders.