BIOTIC Species Information for Carcinus maenas
|Researched by||Ken Neal & Paolo Pizzolla||Data supplied by||MarLIN|
|Refereed by||This information is not refereed.|
|Reproductive Season||See additional information||Reproductive Location||As adult|
|Reproductive frequency||Annual protracted||Regeneration potential||No|
|Life span||6-10 years||Age at reproductive maturity||1-2 years|
|Generation time||1-2 years||Fecundity||Insufficient information|
|Egg/propagule size||Up to 185,000 eggs.||Fertilization type||Internal|
|Reproduction Preferences Additional Information||Duration of reproductive season is related to geographical location. Egg-bearing females can be found year-round in the south of England, between January and April/May in the Bristol Channel and Wash area and only in spring in northern Scotland (Ingle, 1980).
In areas where there is a defined reproductive season, females aggregate at 'hotspots' and males compete for copulatory opportunities (van der Meeren, 1994). Males preferentially select females with a carapace width 10 mm smaller than their own but are not size selective below this threshold and do not select females on the basis of imminence of moult (Reid et al., 1994). Males 65 mm carapace width or more are large enough to dominate competitive interactions and often mate with several females. However, males of this size only make up approximately 5% of the population (van der Meeren, 1994). Unmated males will try to displace males in precopula (a male carrying a female beneath its body held by one of the legs, prior to the female moulting) and always loses out to a male that has a carapace width 9 mm or larger than its own. Males that are similar size are likely to win intrasex conflicts 50% of the time (Reid et al., 1994).
After moulting the 'soft' female is turned over by the male and copulation ensues through modified pleopods on the much reduced abdomen. As with most crabs, the female bears the fertilized eggs in a mass held between the abdomen and underside of the carapace. Females are berried for up to 4 months, depending on temperature, before the eggs hatch in spring/summer. Females in estuaries migrate to the mouth of the estuary to release larvae at night on ebb tides into fully saline water (Queiroga, 1996). At the southern limit of its range, larvae are released in winter when water temperatures are cooler (Sprung, 2001). Carcinus maenas was reported to breed only at temperatures below 18°C (Crothers, 1967). The maximum fecundity recorded was 185,000 eggs (Crothers, 1967).
|Reproduction References||Queiroga, 1996, Crothers, 1967, Ingle, 1980, Meeren van der, 1994, Reid et al., 1994, Sprung, 2001,|