The Chesapeake Bay and the Blue Crab GK-12 SUNRISE Camp August 3, 2009

The Chesapeake Bay

Blue Crabs

History of Crabbing

Why are Blue Crabs Decreasing in the Chesapeake Bay? Hypotheses:

Blue Crabs

Female vs Male Blue Crabs

Male or Female?

Female Blue Crabs Yellow and orange sponge crabs can be kept, brown to black sponge crabs should be returned to the water

Crab Collection

Blue Crab Observations When blue crabs “hatch,” they are very small and called larvae. A female blue crab can release as many as 8 million eggs at a time! Blue crabs undergo metamorphosis, or change shape, from larvae to adults. They change their shape through molting, or shedding their old exoskeleton and making a larger new exoskeleton.

Blue Crab Life Cycle

Crab Sizes 1 millimeter long 1 millimeter long 2.5 millimeters long

Observing Blue Crab Larvae Using the microscopes, look at the blue crab larvae and draw what you see. What do you think larvae eat? How do you think the larvae move?

Observing Juvenile Blue Crabs Watch your juvenile blue crab move in the aquarium. How do they move? How many legs does your crab have? Some crabs may be regenerating legs. How big is your crab? Use the calipers to measure your crab’s carapace width.

How do Blue Crabs Molt? Observe the blue crab molts. Look, but do not touch as they are very fragile. How do you think a crab sheds his old exoskeleton? http://www.youtube.com/watch?v=RU674_dJhA4

Blue Crabs Are a type of crustacean and related to lobsters and even insects. They have a hard exoskeleton which protects them. They can live about 6 years in the Bay. They are scavengers and will eat whatever they come across at the bottom of the Bay including plants and animals.

Blue Crab Life Cycle 2.5mm =100 days old Age range= 50 to 100 days Up to 50 days 18 months old-6 years old 12.5cm and larger

Blue Crabs are Decapods

How old are our crabs? The carapace width of a crab gives scientists a general idea of how old the crab is. Age of Crab (Days) Carapace Width (mm)

Oysters filtering http://www.youtube.com/watch?v=VTuBbuUro4g&feature=channel