Lobsters are extraordinary, and though we’re enjoying a population boom right now, they are in danger of disappearing from the Gulf of Maine.

Maine lobstermen have been harvesting more than 100 million pounds of lobster annually since 2011, but observers fear the boom is an indicator of changing ocean temperatures. As southern New England water temperatures have increased to levels inhospitable to lobsters (the ideal water temperature for lobsters is between 54 and 64 degrees), they have migrated north to our waters. But as those temperatures keep rising (the Gulf of Maine is warming faster than 99% of the world’s oceans), lobsters will have to move north again to survive. Populations—and lobstermen’s hauls—will drop in the Gulf of Maine.

Why does water temperature make such a difference? Part of the answer lies in the complicated molting process lobsters undergo as they grow.

Due to their rigid exoskeletons, lobsters molt as many as 25 times in their first seven years of life. (After seven years, that number decreases to once or twice a year.) They are incredibly vulnerable to predators after molting, and must hide as they grow a new shell. Water at the Gulf of Maine’s current temperatures accelerates the exoskeleton’s growth (and faster shell growth means less time exposed to predation).

As things are, only one-tenth of one percent of hatched lobster eggs survive to adulthood; anything that increases mortality rates (such as less-than-ideal water temperature) could prove catastrophic. When hatchlings are in the planktonic phase, living in the top meter of ocean water, their growth is strongly affected by water temperature. Since here they are particularly vulnerable to predators, the sooner lobsters grow out of this phase, the better for the survival of the species. Until they reach maturity at about seven years, they progress through a number of equally vulnerable stages. But if they survive (and elude the traps), they can live for 100 years.

Clearly, every stage of growth is affected by water temperature, which is why as Gulf of Maine temperatures continue rising, the state’s most iconic animal may soon begin disappearing. This is bad news for Maine’s lobster industry, which has already experienced setbacks, most recently a federal judge’s ruling that the industry will lose its sustainability certification on August 31.

Combine that with cratering prices due to international tariffs and a drop in demand during COVID-19, and lobstermen are up against it. But those plying the coastal waters are a resilient bunch, and no doubt will overcome these hurdles, remaining a vital presence in the Boothbay region and up and down Maine’s coast, as long as the lobsters are there.

Given what we know of climate change and the lobster’s biology, that is sadly no sure thing.