The body form resembles that of adults. Juveniles live on the sea floor among rocks, algae and seagrass beds in shallow waters. With increasing size, they move to deeper waters and as they mature they migrate to seaward reefs. To grow, spiny lobsters must shed their hard outer skeleton by molting, just as other crustaceans do. The soft animal quickly absorbs water, expands and the largernew carapace hardens.
Young lobsters molt often, older ones less frequently, perhaps only once a year.
When lobsters mate, principally from March through July, the male deposits a sperm mass, called a spermatophore, or tarspot, on the female. During spawning, the female discharges eggs which are fertilized as they pass over the spermatophore. She may release from 250,000 to a million eggs each time she spawns. Eggs hatch after three to four weeks and the complex life cycle begins anew with the microscopic phyllosome larvae. Migration Much of the life of a spiny lobster involves travel.