However, there’s a bigger obstacle facing female crabs in the Chesapeake. (Credit: SERC & Marine Ecology Progress Series) Blue circles show where scientists found crabs during July sampling (2015-2017) for the Chesapeake Multispecies Monitoring and Assessment Program. The Chesapeake summer spawning sanctuary (striped) protects females from harvesting from June to mid-September.
It could be those sperm were never viable in the first place. The sperm could get lost as the sperm plug-a parting “gift” from her male partner to ensure it is his sperm she retains-breaks down. While that may seem like a lot, Ogburn’s team discovered female crabs lose up to 95% of that sperm in the next couple months, before they even have a chance to fertilize any eggs. In a single mating, a male crab could give a female anywhere from 770 million to 3 billion sperm. They wanted to estimate how many sperm they received during mating, and compare them to crabs that had started producing broods. They were looking for females that had recently mated but hadn’t produced any eggs yet. His team began collecting female blue crabs in Chesapeake Bay six years ago. Ogburn leads SERC’s Fisheries Conservation Lab. “So when they mate, a female isn’t going to get as much sperm as she normally would.” “If there aren’t a lot of males and there are still a lot of females that are trying to mate, then the males might mate more frequently than they’re able to rebuild their stores of sperm,” he said. That could leave the remaining males stretched thin, he pointed out. In Chesapeake Bay, the fishery encourages harvesting more males than females. “What they get during that timeframe is all they have for reproduction for the rest of their life,” said Matt Ogburn, lead author of the study. During this time, she mates with one or possibly more male crabs and gets all the sperm she’ll ever receive. Unlike some crab species, a female blue crab mates for just one period in her life-within a week or so after shedding her shell for the last time. It boils down to one inconvenient truth: Female blue crabs have an extremely short biological clock. After mating, the male crab will often cradle the female to protect her from predators while she grows her shell back-and to prevent other males from mating with her. *The amount of gear is per boat regardless of the number of licensees or individuals on board.Two blue crabs mating.
Setting gear and catching crabs is allowed during the following time periods: See Recreational Crabbing Licenses & Crab Pot Registration.
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