Water is heating up.

As the inshore shallow bays, sounds and other crabbing waters heat up we find the larger crabs seeking deeper water and are replaced on most piers with smaller crabs.
It may be a good time to go fishing and wait till late September when the inshore waters cool off a bit.
Crabbing remains good in the cooler waters of the north east throughout the summer months but declines dramatically south of the Chesapeake Bay region.

NODC Coastal Water Temperature Table