As early as the 1850s, fishermen from Maine and Massachusetts began to pester their governments to do something about declining cod catches. Those men fished with hooks and lines from small wooden sailboats and rowboats. Fearing “the material injury of the codfishing interests of this state” by increased fishing for menhaden, a critical forage fish for cod, fishermen from Gouldsboro, Me., implored the Legislature in 1857 to limit menhaden hauls.

Yet annual cod landings in the Gulf of Maine continued to slide, from about 70,000 metric tons in 1861 to about 54,000 metric tons in 1880, to about 20,000 tons in the 1920s, to just a few thousand metric tons in recent years. There have been a few upticks along the way, such as one bumper year in the mid-1980s when the cod catch reached 25,000 tons (due, in part, to an unnecessarily large expansion of the fishing fleet), but for the most part the trend has been noticeably downward since the era of the Civil War. There have been plenty of warnings along the way. Maine’s fishery commissioner, Edwin W. Gould, spoke out plainly in 1892. “It is the same old story,” he said. “The buffalo is gone; the whale is disappearing; the seal fishery is threatened with destruction.” For Mr. Gould, the path forward was clear: “Fish need protection.”

In July 1914, after more than 40 years of reports on declining fishery resources by the United States Fish Commission and state fish commissions, The New York Times ran an article forecasting disaster. “Extermination Threatens American Sea Fishes — Cost to Consumer Has Risen between 10 and 600 Per Cent Because of Decrease in Supply.”

But that was right before a technological revolution in the fisheries. Sails and oars and hooks and lines were about to be replaced by steam and diesel engines, and massive nets dragged along the bottom that snared every fish in their path. Decades of well-founded concerns about depletion were overwhelmed by an avalanche of cheap fish. The new generation of draggers could fish faster, harder and deeper for the few fish that remained. Fishermen breathed a sigh of relief.

Twentieth-century cod populations, ravaged by draggers’ efficiency, declined further. In 1954 a fisheries economist from Boston charged fishing interests with continuing “to exploit recklessly the limited self-renewing stocks of these species.” That was just before the first factory-equipped freezer-trawler arrived at the prime fishing waters around the Grand Banks off Newfoundland from Europe. The size of an ocean liner, it could scoop up everything in its wake. Those ships made the steam-powered draggers from 1914 look positively quaint. And they caught lots of fish.