In these days of ever-diminishing fish stocks and major threats to marine ecosystems, good news is hard to come by. But over the past few years, one fish species in particular–the Atlantic Haddock (Melanogrammus aeglefinus)–has made a dramatic comeback, surpassing even peak levels from pre-decline years.
A July 1, 2009 feature article in The Scientist–‘The Great Haddock Revival’ (by Kirsten Weir)–details the remarkable rebound of this once decimated, commercial fish stock. While scientists are still debating the cause(s) of this, New England fishermen are nothing short of exuberant–especially given the concurrent decline of multiple, commercial “ground fish” stocks, such as cod, halibut, and pollock.
The decline of commercially valuable ground fish stocks is symptomatic of the global, over-fishing crisis. Perhaps no other region on the globe is more illustrative of this crisis than New England (the region that extends from the states of Connecticut and Rhode Island in the south to the state of Maine in the north), whose large-scale, commercial fishing industry goes back 400 years. But from the 1930’s to the 1990’s, most of the commercial fish stocks had been depleted from over-fishing. Currently, bottom feeding lobsters comprise the vast majority of gulf of Maine fishermen “landings”.
A federal law governing the nation’s fisheries, reauthorized in 2007, mandates that a majority of fish stocks be “rebuilt” by 2014–no small challenge–especially given that the same law stipulates that each fishery maintain a “continuous optimum yield.”
According to The New England Fisheries Management Council (which regulates fishing from Connecticut to Maine), 13 of the 19 ground fish stocks, which include halibut, hake, pollock, pout, yellowtail and winter flounders, are currently over-fished, and are still in a major state of decline. The lone exception is the haddock. Further, the good news about haddock is not a small-scale or local phenomenon; of the two major, separate haddock stocks within U.S. waters (one on Georges Bank, one farther north, in the Gulf of Maine), both fisheries are considered “recovered”.
Marine scientists are uncertain as to the cause of this remarkable comeback. Some insist that this is solely due to the past decade of good management practices. Yet, most other protected/regulated species have not had such dramatic rebound numbers. So, some scientists think that it’s as much the result of good luck (and timing) than anything else.
For example, numbers of Atlantic Cod–a major predator of ground fish, crustaceans, and other marine species–have been in serious decline for many years. Thus, without this predator population in large numbers, prey species like haddock may have been given some “breathing room” to recover. Also, some fish species occasionally (randomly) experience a population boom. According to the article: “Between 1995 and 2000, the average number of recruits, or fish surviving to age one year, was 22 million fish per year. The 2003 Georges Bank year class numbered 789 million.”
A remarkable recovery indeed.
Other researchers maintain that changes in oceanic currents have favored haddock eggs, which are typically deposited in shallow waters (such as on George’s bank), but which are commonly washed out to see in massive numbers. The lucky current shift, they believe, has kept much more of the eggs in these shallower waters, thus enabling the population boom. This theory is challenged, however, by other researchers who maintain that such a population boom could not be achieved without there first being a dramatic increase in the species’ total biomass (a gauge of the relative health of a fishery stock), given that haddock were in such a critical state of decline prior to 2003.
Under time constraints, marine scientists hope to pin down the exact cause(s) of this success story so that it/they can be repeated, possibly, with other fish species.
photo credit: Steven G. Johnson via Wikipedia.org