A two-decades-long lobster boom appears to be ending as mysteriously as it began.

A report on Quartz.com says the number of baby lobsters along Maine’s coast has plummeted, although the population of breeding lobsters is at an all-time high.

Since Maine now produces around 85 percent of the United States’ lobsters, that could be a big problem for lobster fans.

Quartz reports that no one really knows why Maine lobstermen are landing so many lobsters – 124 million pounds in 2014, six times the amount harvested in 1984. Warmer sea temperatures, which speed lobster growth and help baby lobsters to survive; and commercial fishing that eliminated many of the lobster’s natural predators, are likely factors.

The warmer water may also explain the drop in baby lobsters. Mother lobsters may be making their homes in deeper waters, further offshore, making it more difficult to track the babies. Or the eggs are maturing and hatching too far offshore, carrying the babies out to sea into waters too cold for their survival.