Maryland natural resources officials have decided to cut the female blue crab harvest by 10 percent with hopes of keeping more crabs in the water so that they can reproduce.

State officials made the decision after analyzing the Winter Dredge Survey numbers. The survey counted 147 million female crabs — double the 70 million that is the healthy abundance threshold. But there was poor reproduction in 2013, and scientists do not want the population to fall back into crisis. The total number of blue crabs dropped from 765 million to 300 million, and juveniles dropped from 581 million to 111 million.

The cuts will come in the form of bushel limits that the department will attach to the different kinds of licenses crabbers can have. The licenses range from an unlimited trotline license and 50 pots to a 900-pot license, which a boat captain can obtain if he also has two mates on board.

The bushel limit for each type of license will change every month. It began in May. Maryland closes its season on female crabs Nov. 10, and crabbing ends for the year Dec. 15. The state already forbids recreational crabbers from keeping any females.

The formula for the cut is complicated, acknowledged Brenda Davis, the blue crab manager for the Maryland Department of Natural Resources. That is because doing a simple 10 percent cut wouldn't lead to the necessary reductions, as many crabbers are already fishing below their limits.

"The overall result in the reduction of bushels is a 10 percent reduction in mature female harvest, but the reduction of bushels is actually greater than that," Davis said. "Having it tiered by the license type makes it a bit more equitable across the fishery."

Virginia already has taken action to reduce its female crab harvest, which accounts for most of the state's catch. Last November, the state enacted daily bushel limits that covered the entire season and were based on license types. They plan to close the female fishery on Nov. 20 instead of on Dec. 15.

"These actions will reduce Virginia's female crab harvest this year," said John Bull, spokesman for the Virginia Marine Resources Commission. "We're looking to see how much it will reduce the female harvest, and if other management restrictions will be necessary later this summer."

The states and the Potomac River Fisheries Commission are coordinating to avoid further problems in the Bay's most valuable commercial fishery. In 2008, governors of both states put in major restrictions and got the federal government to declare the blue crab fishery a disaster in response to a collapse of the crab's population. The states received $15 million to help crabbers who lost their livelihoods.

Davis stressed that the 2008 reductions were doing what they were supposed to do and that the harvest of female crabs remained below the targets.

Environmental factors play a large role in blue crab population levels. Most crabs are hatched near the mouth of the Bay and swept out to sea. Winds and tides then determine how many larval crabs re-enter the Bay, so the juvenile crab population can fluctuate widely.

In the past couple of years, tropical storms Lee and Irene, followed by Hurricane Sandy, dumped lots of sediment on the grass beds. In a dry period after the storms, warm, salty water encouraged large populations of red drum to move into the Chesapeake. Biologists believe the fish ate many of the juvenile crabs.