Females reach sexual maturity at 2 1/2 years of age, males at 3. After mating, a large female lobster can produce thousands of eggs, which she will carry around for up to 9 months. The eggs are attached to the hairs of the pleopods (illustration, a), the swimming legs found on the abdomen. The four pairs of front legs are used for walking, cleaning, excavating, catching prey, etc. While being carried around on the pleopods, the eggs hatch into prelarvae, and the female eventually releases them into the currents. Free swimming larvae, called zoeas, undergo various stages (illustration, I, II, III, IV), molting between each one, to turn into tiny replicas of adult lobsters (illustration, b). During the IV stage, zoeas start settling on the bottom and occupy burrows previously excavated by adults. They'll remain inside them for about a year to escape predators.
Friday, June 11, 2010
I find nature and its creations utterly fascinating, and more astonishing than the creatures our best science fiction writers ever invented. On a trip to a local fishery I bought a few Norway lobsters, Nephrops norvegicus, and ended up sketching one. The Norway lobster is widely distributed in the Atlantic of northern Europe, but I guess most people, just like myself until two days ago, know little about it. These alien creatures have the ability to discard a limb to escape danger, and regrow it later. They don't reach their full body lenghth of 25 cm by growing gradually, instead they periodically shed their outer shell and absorb water to expand. Exposure to calcium salts present in the water hardens the new soft shell and they won't grow again until the next molt.