THE STRUGGLE over menhaden now agitating Rhode Island has actually been raging intermittently ever since the 1870s. One major difference between then and now is the opposing sides. Today it looks like recreational anglers and environmentalists on one side of a tug-of-war pulling against lobstermen, other commercial fishermen, and the bait fishery on the other. Back then it was the bait fishermen, the lobstermen, other commercial fishermen, and recreational anglers all engaged in battle, sometimes violent, against the main threat to their livelihood and the marine environment: the menhaden reduction industry.

This industry, which had sprung up in the decades after the Civil War, used the newly invented purse seine to scoop up the colossal schools of menhaden that kept our coastal waters clean and fed all the carnivorous fish we so highly value. Dozens of factories then “reduced” the menhaden to industrial commodities, mainly fertilizer and oils used in the rapidly expanding industrial economy. By 1879, there were 13 of these factories in Narragansett Bay alone, and the industry had displaced whaling as the main source of industrial oils.

Commercial fishermen, including those who had been catching relatively modest amounts of menhaden to be used as bait by all commercial and recreational fishers, realized that the reduction industry was destroying the wondrous bounty of fish so crucial to New England. At least one menhaden factory in Maine was actually burned down by rioting commercial fishermen. Maine, where twenty factories had been hastily erected between 1868 and 1878, in 1879 became the first state to outlaw the reduction industry.

But it was too late. In 1879, menhaden were gone from Maine waters. The pattern kept repeating down the Atlantic Coast as the reduction industry destroyed the marine ecology in area after area. State after state followed Maine’s example, outlawing the industry after the damage became too blatant to ignore. Today, 13 of the 15 Atlantic states have banned the industry, leaving only Virginia and North Carolina to allow this senseless strip mining of their bays and all of our offshore waters beyond three miles out.

Those 19th-Century struggles produced the first systematic consciousness of the interdependence of species, an idea central to 19th-Century conservationism and modern environmentalism. At first the concept seemed quite bizarre. The Anglo-American diet does not generally include terrestrial carnivores, so the culture was traditionally hostile to carnivores, such as wolves and foxes, that prey on our delicious sheep, cattle, and chickens. On the other hand, we do love to eat lots of marine carnivores. But the marine carnivores need to feed on the herbivorous menhaden. So it was fishermen, both commercial and recreational, that came to the seemingly outlandish conclusion that we had to protect the prey to preserve our predators. This seemed akin to protecting sheep to preserve our wolves. And yet that is why the Rhode Island Saltwater Anglers Association wants to protect menhaden, in order to preserve our striped bass, bluefish, and other vicious predators.

It was not until the late 20th Century that people understood the other vital reason to protect menhaden. These oily, smelly little fish are the indispensable cleaners of our inshore waters, most especially estuaries like Narragansett Bay that otherwise, overloaded with nitrogen, get choked with potentially devastating blooms of algae. Algae and detritus are menhadens’ main diet. Working in tandem with the Narragansett’s other stupendous filtering machine — oysters — menhaden used to keep the Bay clean and pulsing with a spectacular population of fish and shellfish. Algae could not mushroom into killer blooms, there were no dead zones, and sunlight could penetrate clear water to support the vegetation that thrived on the Bay’s bottom, providing oxygen and habitat for fish and shellfish.

Today, alas, recreational anglers, lobstermen, the bait fishery, other commercial fishermen, and environmentalists find themselves squabbling over the pitiful remains of menhaden left over by the rapacious reduction industry. On the Atlantic coast, that industry now consists of a single monopoly, the Houston-based Omega Protein. Having ravaged the great Chesapeake Bay to the brink of ecological collapse, Omega is now sending its fleet of spotter plane and eleven factory ships up the Atlantic seaboard to decimate the surviving oceanic schools. Whatever policy Rhode Island adopts to deal with any immediate crisis in Narragansett Bay, we will not have enough menhaden to support the health of the Bay, feed all the fish and lobsters, and provide bait for recreational and commercial fishing until we stop the “reduction” of the most important fish in the sea to industrial oils and cat food.

H. Bruce Franklin is the author of The Most Important Fish in the Sea: Menhaden and America, which was published in April by Island Press.