Habitat

Adult blue crabs are most abundant in estuarine waters and they can tolerate temperatures of 15˚C to 33˚C with the optimum being around 20˚C.  Blue crabs can tolerate salinities 0 ppt to 32+ ppt, but males are concentrated closer to river deltas in water that has a salinity of 3 ppt to 15 ppt, while females are commonly found further away from the delta in salinities of 10 ppt to 32+ ppt.  Blue crabs have been found to tolerate oxygen levels as low as 20% saturation.