On land, plants are at the bottom of the food chain, eaten by many herbivores—mice, rabbits, cattle, insects, and so on. In the ocean, plants are also at the bottom of the food chain. The difference is, there’s only one main herbivore: menhaden. The other filter feeders—like baleen whales, herring, and shad—eat zooplankton (tiny animals).
This gives menhaden an extraordinary weight in the oceanic ecosystem: they are the main food source of the entire food web above, and the main species keeping the ecosystem healthy, by clearing the water of excess algae.
Unfortunately, as H. Bruce Franklin documents in “The Most Important Fish in the Sea: Menhaden and America,” they’re almost all gone. And one company, Omega Protein, is systematically eliminating the few that remain, for fishmeal and poultry feed.
This is a book review of sorts and a very sad report of the start of a food chain collapse.