The writer is a former sports columnist for The Post.

Two years ago, you could pretty much bank on it: Leave the dock at 5:30 or 6 a.m. and be back by 9 with a bushel or so of scrappy male crabs. Then it was just a matter of hooking up the cooker, herding the crabs into the steamer and sitting back for the 25 minutes or so it takes to turn them red and scrumptious.

In the evening it was crabs for six or eight or however many you could gather, followed by a picking session that left you with a pound or two of flaky white meat for crabcakes. That was the norm, from June to September, as it had been for the decade or more since I took up crabbing and for a century before that. Sometimes it was more than a bushel, sometimes less, but always there was a proper mess for supper if you took the trouble to go out.

Last year the bottom fell out. No one is quite sure why, but after an initial run in June, the crabs went scarce. It was eerie, because even in mediocre crabbing years, you catch a lot of little throwbacks, and in the fall there were always many females, which recreational crabbers are required to toss back for conservation. (Commercial crabbers, for inscrutable reasons, are allowed to keep females.)

By last July and August, my Annapolis trotlining partner, Gene Miller, and I had scaled down our aspirations, but we still went. Instead of a bushel, we’d shoot to catch a dozen or dozen and a half of good jimmies, enough for lunch. I talked to recreational crabbers around the Chesapeake who had come to the same decision, and no one was complaining. They weren’t going hungry. It’s a sport. But they shared the same deep foreboding. If there were no little ones, and hardly any females, what would 2014 bring?

The answer is now in hand: Nothing. No crabs. The last signature species of the Chesapeake to withstand the pressures of overexploitation and declining habitat has all but disappeared from the waters around Annapolis, which locals still affectionately call Crabtown. Reports from elsewhere are no better. Like oysters, shad, herring, rockfish and yellow perch, crabs have vanished.

Aha! you say, but didn’t yellow perch and rockfish recover from near annihilation after draconian measures were taken to reduce the catch of both, including a five-year moratorium on fishing for rock in the 1980s? And what about Canada geese? Weren’t they on the verge of disappearing, too, before Maryland shut down hunting in the 1990s?

Good ideas have a way of working out, and the time has come to stop pussyfooting around and shut down crabbing for a few years, to give the delectable crustaceans a chance to recover the way geese, yellow perch and rockfish did. This idea will not go over well with the people who make their living by catching, cooking, serving, picking and selling the “beautiful swimmers” that William Warner won a Pulitzer Prize writing so eloquently about. But if somebody doesn’t stop them soon, they’re all going to be out of business anyway, like the Chesapeake shad and herring fishermen and oystermen of long ago.

The good news is that there are still crabs around and that they are a remarkably resilient species. The life cycle is short and their reproductive capacity so vigorous that we could have abundances back within a year or two, if we just leave them alone.

Among the most extraordinary political steps taken was Maryland Gov. Harry Hughes’s unilateral declaration of a rockfish moratorium when faced with becoming the villain on whose watch the Maryland state fish went under. Can we expect that kind of courage from Gov. Martin O’Malley (D)?

Don’t expect anything brave from the Chesapeake Bay Foundation, which seems to spend all its time mapping fundraising strategies so it can build a new wing on the palace on the bay it calls headquarters. A look at CBF’s Web site reveals not one word about this summer’s collapse of the blue crab. Is it even aware?

We have all watched critical Chesapeake resources dwindle to nothing, victims of declining habitat and ever more efficient methods of exploitation. At some point, these resources either go away or somebody puts up a hand and says: Stop! With blue crabs, that time is now — or never.