We’re Talking Crabs – part 1

It’s the peak of crabbing season here and this is all about crabs and crabbing. I am told that when get on a subject that interests me I often have to be brought up sharply with a loud “Shut up man! You’re boring people”.  So don’t say you were not warned.

The crabs in question are the Atlantic Blue Crab, more specifically those that thrive in what H. L. Mencken (one of my favorite drunks) called “that great protein factory, Chesapeake Bay”.

Here’s a bushel basket of blues just to set the scene

The Blue Crab’s official name is Callinectes sapidus (the Savory Beautiful Swimmer – for once better in English than Greek).  Each year about 100 million pounds of blue crabs are harvested from the Chesapeake Bay, forming about one third of the total catch in the USA. They are not caught by fishermen, any self respecting crabber calls himself a waterman and it is more a description of his whole life that his occupation. In general the watermen live in communities dominated by the waters of the bay, communities with names like Bivalve and Ocracoke or Smith and Tangier Island. In the winter they dredge or tong for oysters (“arsters” as they would say) and in spring and summer harvest crabs (“Crebs” is as close as I can get in English).

The Chesapeake Bay catch numbers are probably understated because everyone with an inch of waterfront is allowed to have a few crab pots in the water around their property, without a license, and in the case of the local creek we take a few dozen crabs every week in the summer for our own use.

Like all creatures with their skeleton on the outside, crabs grow by moulting, shedding their shell four or five times before they mature. The academics call this process “ecdysis” and it’s a grand word to use to win a game of Scrabble, it always produces a shout of denial and a run for the dictionary.

Legal crabs can be quickly identified, they must be male and be at least 5 inches across the widest part of the shell (the spikes). Both of these are eminently logical rules, the size means only fully mature crabs are harvested, and the male part? Well, as in other species (arguably even our own) the vast majority of males are redundant, very few are needed for the species to prosper, and the rest are just taking up valuable space — anyway back to the crabs.

Both sexes share some physical features, both have a pair of grasping claws up front, six pairs of legs for walking and a pair of paddle shaped swimming appendages bringing up the rear (known as “swimmers” or “backfins”). They eat pretty much anything alive or dead, and it’s probably a good thing when we catch them that we do not know what their last meal may have been.

How, you may ask, does the ordinary Joe determine which crab is a male and which is a female? Well the crabs have made it very easy.

This is a male and on its underside it has a feature which “looks like the Washington Monument” according to a website I just found. I have lived here for thirty years and have never heard any waterman describe it that way, (I’m not at all sure many watermen know, or care, what the Washington Monument looks like). They all claim the feature bears a striking resemblance to that most private part of the male anatomy and pronounces “I am a male”. Incidentally, as we will discuss later, large male crabs are here called “Jimmies”, in Britain they might well be called “John Thomases”

The sacred female?  Well here’s the underside of a mature female.

She has what the same website says ”looks like the Senate Building”, does it hell! Watermen universally claim it is a fair representation of one of the second most private parts of the female anatomy, and pronounces even to the casual observer:   “I am female, leave me alone”.   Again echoes of Homo Sapiens.   Incidentally the “Rounded abdominal apron” as the academics call it, only appears after the final moult of the female and is a sure sign of a sexually mature crab, a “Sook” in waterman’s language.

Male crabs continue to moult (and to grow) even in maturity and males of eight inches or more in size can be often be found . Again echoes …… anyway back to the crabs.

Speaking of sex, one may wonder how it is possible for two armored crabs to reproduce. Well gather round and I’ll tell you a story to warm your hearts.

Male crabs are irresistibly drawn to females as the females approach their final moult. The watermen call any immature females “Sallys”. How the Jimmies know the Sallys are about to undergo their final moult is not known to watermen who claim “them Jimmies never miss”, however the literature says otherwise and Jimmies in captivity have been seen attempting to mate with empty crab shells, fake crabs, other males and immature females. So much for folklore.

The Jimmies start “acting horny” according to the watermen “and get up on their tippy toes and do a little dance” in front of any Sallys near to moult, the Jimmies spread their claws and thrash their swimmers to attract attention. After some hours of this, and if the Sally likes what she sees, she gently backs under the Jimmy, he folds his six pairs of legs around her and carries her off, swimming for miles looking for the ideal mating spot, usually in a patch of eel grass in the tidal shallows. This pair, watermen call them “Doublers”, can be commonly seen on a summer’s day, he swimming tirelessly, close to the surface with his beloved clasped beneath him and she apparently quite content.

They may stay together like this for up to five days as the Sally prepares to moult and only when she emerges from her hard shell and before a new shell has had time to harden can the process continue. First, while the new shell is still soft the female ingests water and grows, the soft shell expanding to a new size, then still during this soft stage the male gently turns the female over beneath him, and while they embrace in an unmistakable act of tenderness, he deposits several sperm packages in the female (who only mates but once). The two crabs remain together for up to two more days until the female’s new shell has fully hardened. When they separate the females (now “Sooks”) migrate instinctively towards more saline water moving Southward down the bay to spawn. This migration may be long and often is broken by the coming of winter when the crabs hibernate at the bottom of the deepest part of the bay, but even if the journey is temporarily stalled by winter the Sook can still fertilize a first batch of eggs during the following spring. In fact she can fertilize up to seven batches of eggs per year for up to three years using the sperm from her only mating.

She will carry each batch of eggs clustered on her abdomen for several weeks while they hatch, releasing them only in conditions of near ocean salinity to be swept into the Atlantic to grow.
Watermen call a sook in this condition a “sponge” crab due to the appearance of the egg mass.

The hatched eggs are technically called  zoeae (another Scrabble winner), and look more like tiny shrimp than crabs which again can only grow by moulting. After six of seven moults the form of the crab changes so drastically it is given a new name – Megalops, it now looks like a tiny crab and will continue to have this form to maturity.

Well this got too long to finish in one post so next we can talk about catching crabs and maybe a last episode about cooking and eating.   How’s that for excitement?