While April 1st might have been just another day of social distancing for some of us, for others, it was the start of something new. On Wednesday, the season for commercial harvest of blue crabs in the Chesapeake Bay opened 30 minutes after sunrise. Not every crabber was out on the water that day, but a few braved the chilly morning to try their hand at catching the early crabs. However, depending on where a waterman sets their lay, it may be hard to find crabs this time of year.
Blue crabs originated in the tropics and spread from there into colder, temperate regions. In the mid-Atlantic, winters are too cold for normal blue crab activity, so crabs enter a sort of hibernation stage. Buried in the mud through the cold winter months, a crab’s metabolism slows and molting (the shedding of the hard exoskeleton or shell) stops completely. When water temperatures begin to warm, crabs slowly awaken from their winter slumber and begin to search out food.
Currently, Chesapeake Bay water temperatures are hovering around 50 degrees Fahrenheit (around 10 degrees Celsius). This is generally considered the temperature at which blue crabs become active, though it will likely still be awhile before we see high numbers of adult crabs in the tributaries. This is because larger crabs typically prefer to bury in deeper, saltier regions of the Chesapeake Bay. In addition, most mature female crabs are far to the south, in Virginia waters, either having just spawned in the fall, or preparing to spawn in the spring and summer. Scientists have also found that large crabs are more likely to die due to cold stress in fresher water, compared to saltier water. Thankfully, since we had such a mild winter, the number of crabs that died due to cold stress this winter is likely low.
We’ll know a little better how the blue crab population is doing this year when the winter dredge survey results are made available. The Maryland Department of Natural Resources and the Virginia Institute of Marine Science conduct the dredge survey from December through March to monitor blue crab population numbers in the Chesapeake Bay. They look at the number of adult crabs, the number of juvenile crabs, and the total crab population. These numbers can give us a good idea of how the commercial blue crab fishery will do later in the year. For example, last year (2019), showed a low density (5.24 crabs/1000 m2) of male crabs above 5 inches, but a high density (28.64 crabs/1000m2) of all crabs over 2.4 inches in size. These numbers meant a slow start to the commercial fishery, with relatively few large crabs early in the year and an increase in catch numbers by the summer, when many of those smaller crabs grew to the minimum harvest size. You can find the numbers here: https://dnr.maryland.gov/fisheries/Pages/blue-crab/dredge.aspx
This slow start to the Chesapeake Bay blue crab season means that while you may be tempted to buy crabs early in the year, if you want the best crabs, be patient or know exactly where your crabs are coming from. Because crabs are active year round in warmer regions, like the Gulf of Mexico, early season and off season crabs and crab meat may not be from the Chesapeake Bay. If you buy pre-made frozen crab cakes, much of that meat is coming from a different species of crab from Asia and not our own blue crab, Callinectes sapidus. It’s always best to buy fresh seafood and know where it’s coming from. This year, that will be more true than ever, as our local economy relies heavily on blue crabs and other commercial fisheries. If you can, buy from local seafood companies that buy direct from local watermen. If you don’t know where your seafood is coming from, ask. Businesses try to provide what their customers want, so if you ask for local crabs and seafood, they will be more inclined to provide it.
After all the social distancing is over, I can think of no better way to celebrate than a bushel of freshly steamed Chesapeake Bay blue crabs shared with family and friends.
Staff Blog: Article written by Dr. Kristen Lycett PhD- Fishmobile Coordinator
Dr. Kristen Lycett PhD
Phillips Wharf Fishmobile Coordinator
Phillips Wharf’s newest staff member and marine estuarine scientist Dr. Kristen Lycett fills the role of Fishmobile Coordinator. She is currently on loan to us from Americorps until August when we hope to secure her full time. Lycett received her Ph.D. from the Marine Estuarine Environmental Science program at the University of Maryland Eastern Shore, where she studied the parasite Hematodinium perezi, which infects blue crabs and other crustaceans.