No. 07–Spring Delicacy, Part II
There are soft shell crabs in local waters year round because crabs are growing and molting virtually throughout the year. It slows down considerably in the winter months since, as with all cold blooded species, the crab’s metabolism and feeding episodes drop with the water temperature. During those months the tidal creeks and rivers are essentially devoid of blue crabs as they have moved to the deeper holes in the sounds and to near shore waters.
The warming waters of spring stir the juices of the over wintering crustaceations leading to their repopulation of the shallows. Spring also heralds the migration of the next generation from off shore hatching grounds to the estuarine nursery. As with their white and brown shrimp distant cousins, blue crab larva require full ocean salinity to survive. The adult females die soon after their offspring hatch and from time to time their lifeless bodies will litter winter shores.
Though crab mating occurs throughout the warm water months because segments of the overall population are in different stages of development over the course of a year, the most intense activity takes place over a relatively few weeks in April and May.
Crabs are able to mate only after the female has molted from her immature to her mature stage and then only for a short period before her new exoskeleton begins to harden. You may have observed double decked crabs. The one on top is the male and they either already have mated or are waiting to do so.
Male crabs release pheromones which serve as an attractant to females which are approaching their immature to mature molt. A female will follow the current borne scent trail to her prospective mate who will take his position atop to establish his preeminence should a potential rival happen along. He will remain with her thus until her molt begins at which point dismounts with claws at the ready to protect his interest.
Mating takes place belly to belly once the female is free of the old shell with the male depositing a spermatophore (packet of sperm) within her. Upon completion of the act the male again cradles her in a protective embrace to remain on guard for the two days it takes for the females new exoskeleton to harden.
Point of fact: Virtually all soft shell crabs consumed by humans are female. During the short commercial season the wily crabbers place big healthy male crabs in the bait compartment of crab pots assuring that all the catch will be females that will be molting before long. The crabs known as peelers are placed in peeler tanks where thy are observed twenty-four hours a day. Upon molting the “softies” are moved to a holding tank for a brief period where they swell to their larger size. They are then removed from the water which stops the hardening process and then refrigerated which puts the creature into stasis and ready for shipping. That’s why they can serve soft shell crab in Denver or Detroit.