Some changes, like warming waters, may eventually make it possible for females to have more broods each year. That applies both offshore, where changing currents and environmental conditions could affect larvae, as well as in the Bay itself. “We don’t have a solid handle on what all the different driving forces are offshore that affect survival of those recruits,” Lipcius said.Ĭlimate change further complicates the crab equation, he said. The larval blue crabs are swept into offshore ocean waters, where they develop for about a month before returning to the Bay. In the Chesapeake Bay, that means females migrate to the mouth of the Bay to spawn. It could also have something to do with the life cycle of blue crabs, which require higher salinities when they are juveniles. Some of the fluctuations could be due to an abundance of invasive predators, like blue catfish. In the meantime, scientists are still working to get a better handle on what’s going on with juvenile crabs. “As long as those remain at a good level, the population as a whole can then recover,” Lipcius said. So far, the number of female crabs has remained above the threshold of concern set by fishery managers.Ī researcher holds two female crabs, identifiable by their U-shaped apron, caught during the winter dredge survey. Each adult female is capable of producing several broods of young crabs every year. The focus on protecting females is due to their importance to the overall resilience of the population, said Rom Lipcius, a professor of Fisheries Science at the Virginia Institute of Marine Science, and head of the lab that conducts the annual dredge survey in Virginia. “These reduced abundances highlight the need to continue to protect adult females in order to help ensure better numbers in the future.” “Although juvenile population estimates can vary greatly from year to year, the 2022 results are the third year of below-average numbers in this segment of the population,” Chris Moore, CBF’s Senior Regional Ecosystem Scientist, said at the time. It also showed a continuing low number of juvenile crabs. Last year, the survey showed the overall crab population dropped for the third consecutive year to its lowest level in the survey’s 33-year history. This year’s survey results, which won’t be released for another couple months, are anxiously awaited. On March 16, VIMS researchers sampled crabs at 18 locations in the Lower Bay, marked by green squares on this electronic navigational chart.
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