Molt and reproduction of the European green crab Carcinus maenas (Decapoda: Portunidae) in Patagonia, Argentina

Abstract

The green crab Carcinus maenas, a decapod crustacean native to thenortheastern Atlantic, has beeninvading distant areas, mainly for the last 25 years. This speciesis currently distributed along the coasts of thenortheastern Pacific, South Africa, Japan, South Australia, Tasmania,and western and eastern North America,among others. Here we provide information on the biology of the greencrab occurring in the central area of SanJorge Gulf, Argentina, where it has been established since 1999-2000.Crabs of both sexes were hand-collectedbetween January 2004 and May 2005 from the intertidal zone and theupper sublittoral fringe. Sex, carapacewidth and molting stage were recorded. The reproductive status ofmales was based on the presence of sperm andspermatophores in testes and deferent ducts, and that of females onovarian development and presence-absenceof eggs. Stages of embryonic development for ovigerous females werealso recorded. The most importantphysiological events taking place during the annual cycle of the adultpopulation were as follows: (1) male moltoccurred mainly in November and female molt between January and thebeginning of March; (2) the reproduc-tive season started in January, after a courtship in which the male,larger in size, holds the female until the molt,and spermatophores are ejaculated once the old exoskeleton is castoff; (3) females left the intertidal zone earlyand moved to lower littoral levels during fall and winter; (4) larvaeappeared in September.