Two kinds of active factor in crab hatch water: Ovigerous-Hair Stripping Substance (OHSS) and a proteinase

The embryos of intertidal and estuarine crabs are clustered on the ovigerous seta of the female, where they are ventilated for 2-4 weeks by the female's abdomen. When the embryonic development is complete, hatching occurs and zoea larvae are released into the water. This study indicates that the crab hatch water (i.e., the filtered medium into which zoeas were released) contains at least two kinds of active substance: OHSS (ovigerous-hair stripping substance) and a proteolytic enzyme. Both factors were separated by gel filtration. Powdered fragments of egg capsule were digested by proteinase, suggesting that this enzyme actually acts on the egg capsule. But this activity was at a very low level compared with casein digestion. The proteinase might be digesting the thin, sticky layer enclosing the embryo and would not act on the thick, tough layer constituting the main component of the egg capsule. Therefore, a proteolysis of such low activity could not be expected to cause the egg capsule to rupture.