AC 16, touch 9, flat-footed 16 (+7 natural, -1 size)
Rock crabs can survive out of the water for 1 hour per point of Constitution. Beyond this limit, a rock crab runs the risk of suffocation, as if it were drowning.
This is a Variant Monster. The full stats were not provided by Paizo so some calculations were made. The DM is encouraged to double-check the numbers before using.