User:16vmai/sandbox

Description:

H. sanguineus has a squarish carapace with three teeth along the forward sides; its pereiopods are marked with alternating light and dark bands. The males have a bulb-like structure at the base of the moveable finger on their claws.Other distinguishing features include three spines on each side of the carapace. Adult crabs sizes range from 35-42 mm width (Asian shore crab). These crabs are opportunistic omnivores that tend to favor other animals over algae. As crab density of the invaded area increases, so does the diet breadth, which suggests that competition alters selection of food (brousseau). There currently is no mitigation against these crabs. A natural enemy of H. sanguineus is Sacculina polygenea, a parasite that attacks adult shore crabs and is specific to H. sanguineus (cabi.org).

Distribution:

The native range of the H. Sanguineus is from Peter the Great Bay in southern Russia to Hong Kong. The Hemigrapsus crabs were first found in the United States for the first time in 1988 (Mcdermott, 1991). The larvae are thought to be transported by ballast water of yachts and cargo ships coming from their native breadth (micu). H. Sanguineus was first discovered in North America in Delaware Bay in 1988 (Epifanio).

Ecological Impacts:

The invasion of the habitat by the H. sanguineus has been characterized by rapid geographical expansion and widespread displacement of competing crab species (Epifanio, 2013). Although this species has been introduced to such a large habitat, H. sanguineus is eaten by native crustacean eating fishes. Since the crabs are so abundant, some types of native fish even prefer the invading crab (Heinonen). This may be due to the mouths of fish adapting to the size of H. sanguineus because they are the most abundant food source. On the other hand, native crabs also have adapted to eat H. sanguineus, possibly due to the availability of the food source or as an anti-predator strategy (Heinonen). There is a possibility that H. sanguineus could expand and possibly overwhelm the habitat and out compete native crustaceans, such as the blue crab and lobster.

Habitat Description:

Typically, the crabs live in areas with large rocks, such as in between boulders of rocky shores (Micu). Hemigrapsus sanguineus inhabits many artificial structures such as on oyster reefs (eat the invaders). H. sanguineus can tolerate other habitats, such as salt marshes (cabi.org).

Reproduction:

Female H. sanguineus can produce more than 50,000 eggs at a time, usually in the spring (cabi.org). The eggs then hatch, typically late summer or fall, into larvae and and the juvenile crabs molt in five stages to become megalopae, which typically takes about a month. Once in this stage, the crabs settle and metamorphosize into full grown crabs (cabi.org).

Diet:

Because the crabs are opportunistic omnivores, these crabs will eat anything they can get their mouths around. H. sanguineus prefers to consume animals, but during a period of starvation, these crabs tend to not have a food preference (Brousseau). Most of the animals consumed by H. sanguineus are small invertebrates, such as muscle, snails, and amphipods (cabi.org). The diet of these crabs is overall very broad.