Annihilate an Entire Species of Fish, and Other Easy Ways to Really Mess Things Up
From Omega Protein's perspective, hoovering up menhaden like they're dust bunnies is a great idea. The company's entire business model hinges on transforming the oily fish into everything from livestock feed to omega-3 pills for people. In fact, it owns a monopoly on Atlantic menhaden fishing and processing—and has been doing just that for years. The stock market values Omega Protein at a cool quarter-billion dollars.
For the health of the ecosystem along the East Coast, though, declaring open season on the menhaden really, really sucks, as Alison Fairbrother and Randy Fertel say in their recent Gilt Taste piece, "The Most Important Fish in the Sea." All along the eastern shore, menhaden have entered a phase of calamitous decline. Stocks have plunged 88 percent in the past quarter century, the authors report. As Omega Protein sucks them out of the ocean, things are getting quite out-of-whack down below. Fairbrother and Fertel explain:
[T]heir nutrient-packed bodies are a staple food for dozens of fish species you have heard of, as well as marine mammals and sea birds. Located near the bottom of the food chain, menhaden are the favored prey for many important predators, including striped bass and bluefish, tuna and dolphin, seatrout and mackerel.
And that's not all. "Menhaden are filter feeders, swimming with their mouths open and straining phytoplankton (algae) and other particles with their gills," Fairbrother and Fertel report. The little fish "have been removing damaging particles from our waters since time immemorial."
Thus menhaden have what I call ecological leverage. That is, if you fish them into oblivion, you're not just destroying a single species; you're also threatening to unleash a cascading set of effects that could lead to full-on ecosystem collapse. Other examples of ecological leverage include coral reefs, which act as engines of oceanic biodiversity but are under attack from a variety of forces, and tropical rainforests, which teem with biodiversity, too, and also help stabilize global climate by trapping vast amounts of carbon. We mess with ecological leverage at our peril.
As Fairbrother and Fertel show, menhaden are already displaying their ecological leverage on the Atlantic Coast:
One sign that points to the scale of the problem is that species like striped bass that normally feed on menhaden are displaying symptoms of malnourishment and disease. Seatrout are near their lowest population point on record, in part because of a lack of menhaden. When faced with the loss of both seatrout and menhaden as food, striped bass have been turning to other cherished delicacies. "Striped bass will feed on blue crabs and lobsters when they can't get enough menhaden. We are seeing increased mortality of juvenile lobster and blue crabs," [a prominent fisheries scientist] says.