New England’s stocks of cod—the fish that fed colonists and launched the United States’ first industries—have collapsed almost past the point of recovery, despite aggressive catch restrictions that should have allowed them to rebound.

On Thursday, scientists speaking at a conservation event in Washington, D.C. disclosed why: The Gulf of Maine is warming faster than 99.9 percent of the rest of the oceans. It is happening so quickly that it has harmed cod’s ability to replace its numbers even though fishing had almost ceased.

“In warm years, each female cod produces fewer one-year old fish, and that these young fish are less likely to reach adulthood,” Andrew Pershing, the chief scientific officer of the Gulf of Maine Research Institute, said