What’s the most important fish in the sea?
That distinction often goes to a one-pound creature that most people have never heard of: menhaden.
These fish, which barely reach a foot long, are a critical food source for wildlife such as whales, dolphins, ospreys and eagles. They also are eaten by valuable fish species, including tuna, cod, striped bass and tarpon.
Yet their populations along the Atlantic coast, from Maine to Florida, are at a record low—just 10 percent of historic levels. Fishermen have hauled in billions of menhaden, which are ground up mostly to make fertilizer, pet food, dietary supplements and feed for agricultural animals and farm-raised fish—further increasing demand for the dwindling species.
Menhaden’s decades-long decline is like a vegetable shortage in the grocery store. Without this important food staple, diets are compromised, and it’s a scramble to find suitable substitutes. For example, although these fish once made up 70 percent of the diet of the Chesapeake Bay striped bass, they now account for just 7 percent, and the bass are showing signs of malnutrition and disease.
Scientists suspect the effects of dwindling menhaden are much more widespread. The shortage threatens the Atlantic marine food web and could cripple the commercial and sport fishing industries. Striped bass alone generate $6.9 billion in revenue and 68,000 jobs for East Coast commercial and recreational fishing industries annually, according to a 2005 study by Stripers Forever, a non-profit striped bass conservation group.
With so much at stake, the Atlantic States Marine Fisheries Commission, which manages fishing policies in coastal waters of the 15 Atlantic states, is hosting public hearings this month. The commission will meet in Boston beginning Nov. 7 and will vote on Nov. 9, based on public feedback, on what to do about the threat to menhaden.
Read the full article at Discovery News.
Analysis: The article's claim of an overfished menhaden population is not backed up by the most recent scientific data; instead, the article relies on several flawed metrics to make its case for overfishing. First, it claims that menhaden are at "just 10% of historic levels." This refers to the Maximum Spawning Potential (MSP), an estimate of a theoretical unfished population. While menhaden are currently fished to 10% MSP, that alone is not enough to support the claim of overfishing, as historically menhaden have rarely risen above 10% MSP, and the population has been able to rebuild itself at that level.
Similarly, the articel makes that case that because the percentage of menhaden in bass diets has been reduced from 70% to around 7%, this is both evidence of overfishing and the cause of disease in bass. Bass diets are highly variable, so the presence or absence of menhaden in the diet is not enough to determine overfishing, as bass feed on a variety of species based on their relative location and abundance. The presence of menhaden is also not likely the cause of sickness in bass. A more likely explanation is that oxygen depletion in the waters that bass usually inhabit has forced them into warmer waters to which they are ill-suited, leading them to not feed properly and making them susceptible to disease.
However, a look ah the fisheries data does not reveal a pattern of overfishing. The last stock assessment by the Atlantic States Marine Fisheries Commission concluded that menhaden were not overfished and the the stock had only experienced overfishing once in the last decade.