the green shore crab -- 8/17/22
Today's selection -- from Life Between the Tides by Adam Nicolson. The stalking ground of the green shore crab:
"There are many different sorts of crab in the bay and in creels I have caught them all: the pie-crusted lid of the edible or brown crab; the pink of the swimmers; the dark, furred mystery of the velvets. Those are largely found away from the shore but here, this pool was now to be the stalking ground and manor of the green shore crab, Carcinus maenas, whose Latin name sounds as if it describes its maleficence but signifies only that it likes to eat a little fish, a maena, now and then. The French call it le crab enragé, from its habit of approaching in fury with open claws held aloft.
"I put a small crab trap in there, baited with bacon. Within a few minutes, a green crab was maneuvering towards it, from about four yards away, the smell communicated through the water. It was big, about three inches across, and walked directly towards the trap and then up over its netting, soon finding the inward-reaching, cone-shaped mouth that led towards the bacon. The crab paused there for a good minute, as if questioning the idea of entering this strange, food-rich, unaccustomed place. Was it a trap?
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| Carcinus maenas |
"The smell of bacon must have overcome the wariness and it pushed further in. Six minutes after I had first seen it moving, the crab had fallen down into the trap's belly where it would get to the bacon but from which there was no escape. As it started to couch and hold the bait, two other crabs could be seen approaching from the far side of the pool. The first went past the entrance and in under the trap to the point where it was next to the crab that was already in there. The two of them began to grapple with each other through the net, one with access to the food but trapped, the other with no bacon but free.
"The third, a little pale green one, bundled itself fast across the floor of the pool, climbing and semi-buoyant, with slightly less than neutral buoyancy, looking as if it had about as much gravity in water as an astronaut on the moon. Without pause, a fool rushing in, it flipped down into the trap already occupied by its bigger rival, which now looked suddenly enormous. Perceiving the entrance of the small pale crab, the older one neglected its rival outside and turned towards the newcomer. Young crabs are all green but old ones, or at least crabs which have not moulted for a long time, are flushed red, particularly in the joints of their legs and claws. This beautiful old thing had a grey-green carapace, black at the front and with pale, almost moth-like patterning on its lid, white constellations of dots fanned out like the eyes on a peacock tail.
"Carefully it stirred its bronzy legs, each joint glowing orange like a set of eyes, and greeted the intruder. The drama lasted a few minutes. The little crab retreated to a corner and held its pitiable pale, lime-green claws up towards the enemy. For a moment the big crab picked up the little one in a claw and walked back sideways with it, crabwise, down into the depths of the trap, past the bacon, to a point at the far end where the little crab was held there in its attacker's pincers, delicately as if it were a teacup in a pair of fingers and thumbs, while the young crab's legs flicked and stirred at its undoing.
"I waded in and collected the trap, released both big and little big crab and watched the third walk away quickly past the ochre anemones, heading for the shade of the south wall and a protective stand of bladderwrack.
"It does not take much to see that these animals are brutally successful: efficient and voracious, eating worms, other crustaceans, including their own conspecifics, and many molluscs. They will dominate and transform any coast they find. As aggressive opportunistic predators, with the ability to tolerate wide extremes of heat, salinity and even drought, they have been carried inadvertently in the holds of ships across much of the world, and are now a destructive and alien threat in Japan, Australia and Tasmania, South Africa, Argentina and both coasts of North America, from Newfoundland to Virginia and California to British Columbia. Their only enemy is warm water and although they have often been found there they have yet to colonize the tropics."
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