A blue crab is seen in a container at Janes Island State Park in Crisfield, Md. (Matt McClain/The Washington Post)

Joel Hayden’s investment, tens of thousands of dollars’ worth of yellow-painted wire cages, is spread across his lawn in neat stacks. Just beyond the water’s edge, his paycheck is burrowed in the mud.

It’s the eve of blue crab season for watermen like the 28-year-old Hoopers Island native, and he is sparing no expense to prepare. After all, here at the southern edge of Maryland’s share of the Chesapeake Bay, there is only a short springtime window before the biggest crabs head north to fresher waters.

Next month, Hayden will begin scattering hundreds of the handmade crab pots around nearby creeks. If there are as many of the blue-legged crustaceans as watermen and scientists expect, it will be a busy start to the season.

A decade ago, the bay’s blue crab population was on the brink of collapsing when Maryland and Virginia agreed to dramatically reduce the harvest of young and female crabs. Biologists credit the rules with helping the crab population rebound and stabilize, and mild weather this winter portends a third-straight year of gains in crab numbers.

But the rules could become a victim of their own success.

Officials in Gov. Larry Hogan’s administration said this month that they are willing to consider changes to the harvest limits if crab population growth remains strong, just as they are exploring opening some prosperous oyster sanctuaries to harvest.

For years, watermen from the lower Eastern Shore have begged state officials to ease crab-catch limits. They are hoping changes may be coming from an administration that recently fired a veteran crab scientist and pledged a “customer service”-oriented approach to fishery management.

But other watermen and conservationists fear that a less aggressive management style could set back recent progress.

And they are worried that a change could spur Virginia — where most of the famed Maryland crabs are born — to loosen its own harvest restrictions, as officials are already discussing.

“That’s just a scary thing for me,” said Richard Young, a crabber who sells his harvest at Coveside Crabs in Dundalk. “I look at it as a long-term thing. I want to be able to go out and catch crabs for the rest of my life.”

Biologists say any changes to crab harvest policies would come at a still-critical time for the species, which is naturally prone to erratic swings in fortune.

In 2008, with crab harvests and population estimates among the lowest on record, former Maryland and Virginia governors Martin O’Malley and Tim Kaine signed what was considered a landmark agreement. Through limits on the timing and size of harvests, they cut the harvest of female crabs by more than one-third.

“At the time, scientists were saying the population may be on the precipice of collapse,” said Bruce Vogt, ecosystem science and synthesis manager in the National Oceanic and Atmospheric Administration’s Chesapeake Bay office.

It has worked, Vogt and other scientists say. The number of spawning-age females is approaching the 215 million target they set as necessary for a sustainable population. The total number of crabs has shown steady improvement since 2014.

This season is forecast to be another strong one, coming after a mild winter. Cold temperatures typically kill off a share of the population.

For most watermen around the bay, that is unequivocally good news. The more plentiful and muscular their catch, the more money they make.

On the lower Eastern Shore, though, there are worries local watermen will not share in the bounty as much. The biology and geography of the crab life cycle means they mostly catch small crabs that are picked for crab cake meat — and a rule that predates the 2008 agreement means they have to throw the smallest ones back.

A Maryland crab’s life begins in Virginia’s saltier waters, and its earliest stages of growth happen just offshore. It then relies on tides and weather to make it up the Chesapeake and spends the winter hibernating in the mud before temperatures warm, allowing it to resume growing and molting, ambling its way up and around the bay through the summer.

Because bigger crabs typically leave lower bay tributaries for less salty waters, usually by July 4, the catch there is smaller and less plentiful until crabs pass through on their way south in the fall, Dorchester County watermen say. For much of the summer, they have to throw back a meaningful share of what they catch because it is smaller than state policy allows.

“Sometimes it’ll make the difference between you being able to work and not being able to work,” said Thomas “Bubby” Powley, a Dorchester waterman for 45 years.

Lower Shore watermen have for years pleaded for the ability to catch crabs as small as five inches across throughout the season, which runs from April into December. Under current rules, that minimum size increases by a quarter-inch in July, a significant hardship, they say.

Their request has been repeatedly denied in recent years, according to Brenda Davis, who until February served as manager of the crab fishery for the state Department of Natural Resources. Davis made clear her resistance to changing the rule, and many watermen and environmentalists believe that is what got her fired.

Natural Resources Secretary Mark Belton would not discuss his decision to fire Davis, saying it was a confidential personnel matter. But he told lawmakers the Republican Hogan administration agreed with watermen that they had been ignored under O’Malley, a Democrat, and is “committed to providing the utmost customer service” going forward.

He testified that any policy revisions would depend on the results of an annual crab population survey, expected in early May. If crab numbers rise, “that leaves room for a lot of discussion,” he said.

Others said they are nervous but open to a rule change. They credit the policies with helping them catch bigger, more valuable crabs — but also emphasize that the rules were intended to be slackened if populations grew.

“Most of the guys in the upper part of the bay aren’t for changing it right now,” said Chuckie White, a waterman on Kent Island. “They want a couple years of a really, really good rebound.”

Scientists and bay advocates say loosening the rules now could be dangerous but acknowledge that if the harvest rules work, they should be eased eventually.

Allison Colden, Maryland fisheries scientist for the Chesapeake Bay Foundation, said her organization has “cautious optimism” that the bay’s crabs are more resilient than they were a decade ago.

But the species is prone to suffering from unfavorable weather or predation, she said.

“Given the amount of variability that still exists, we’re at a critical point in determining if that positive trend is going to continue,” she said.

In Virginia, officials have for several years been considering whether to allow, for the first time since the 2008 agreement, wintertime dredging of hibernating crabs. The debate has remained grounded in science and avoided political drama, said Rom Lipcius, a professor at the Virginia Institute of Marine Science who helps lead the annual bay crab survey.

He said he did not think changes in Maryland policy would influence Virginia regulators.

Baltimore Sun