Essay --

REVIEW OF RELATED LITERATURE Hemigrapsus sanguineus Hemigrapsus sanguineus (de Haan, 1835), commonly known as the Asian shore crab, is a brachyuran crab, and is a native species along the western North Pacific coast (Brousseau et al., 2001). Its square and broad carapace has three spines on each side and there finely striated ridge exist under the eye and lateral margin. Its usual size is 30 mm wide but maximum size reported can reach up to 43.9 mm carapace width (CW) (McDermott, 1998). Its color varies from purple, red, green, orange-brown, with the presence of bands along its legs and red spots on the cheliped claws (Poore,2004). Males are characterized by the presence of distinctive fleshy, bulb-like structure at the cheliped base of the dactylus the shape of the flap on the underbelly in males is quite phallic, triangular and pointed. The females are recognized thru the roundness, wider and more oval flap of abdomen morphology. Easily opened flap of female crabs only implies that they are capable of mating. (Poore,2004). The local scope of this crab species is the region of Asia-Pacific (McDermott, 1998). It was observed that this species has penetrated parts of the Europe and North America, specifically France, Netherlands, and Croatia and is now classified to be an invasive species (McDermott, 1991). It is considered invasive because it is capable of reaching high densities and can initiate negative impacts on several small juveniles of native species (Lohrer and Whitlatch, 2002a,b). Asian shore crabs are considered as opportunistic omnivores (McDermott, 1998). They consume a varied kind of plant and animal resources in the field and also when they are in captivity. These resources would include algae, salt marsh grass, a... ...rtional relationship, which implies that the wet weight could give a length estimate of the species’ carapace. Several physico-chemical factors affect the growth and development of crustaceans. Environmental stress in coastline waters is usually caused by organic waste disposal which then results in low amount of important crustaceans harvested in fisheries and can also influence the biodiversity of decapod crabs. The physico-chemical parameters are crucial ecological factors, as they directly affect oxygen consumption, metabolism, growth, moulting, hormones and survival of crustaceans (Varadharajan D et al., 2013). The salinity is one of the main factors that alter the distribution of organisms, and this is likely to affect the decapods crab distribution and production as well. The alkaline pH was observed to be related with increased number of crab species.