For most of the last two decades, the total number of blue crabs in the Chesapeake Bay has lingered below the long-term average. Because blue crabs are so important to the region's ecosystem and economy, both Maryland and Virginia monitor the blue crab population through an annual Winter Dredge Survey. The crabs that are collected at each of the survey's 1,500 sampling sites are measured, weighed, sexed and aged, and the data is used to estimate the number of young crabs entering the population, the number of female crabs old enough to spawn and the total number of harvestable crabs in the Bay.
According to data from the Winter Dredge Survey, an estimated 455 million blue crabs lived in the Bay in 2017. While this marks an 18 percent decrease from the previous year, experts called the population stable.
In the Chesapeake Bay Watershed Agreement, the Chesapeake Bay Program set a population target and an overfishing threshold for adult female blue crabs. In 2017, an estimated 254 million adult female blue crabs lived in the Bay, compared with 194 million in 2016. This number is above the 70 million overfishing threshold and the 215 million target and marks the highest amount of adult females ever recorded by the Winter Dredge Survey. Based on this fact, experts confirmed the blue crab stock is not depleted. And because only 16 percent of the female blue crab population was harvested in 2016, experts stated overfishing is not occurring.
Blue crabs are vulnerable to pollution, habitat loss and harvest pressure. Water quality improvements, underwater grass restoration and proper harvest management will be critical to maintaining this valuable resource.