Deadliest Catch: Population Density and Characteristic Study of the Invasive Green Crab (Carcinus maenas)

摘要

The European green crab (Carcinus maenas) is an invasive littoral crab that was first introduced to North Americas eastern coast in the early 1800s4. It is an omnivorous scavenger and a voracious predator with a diet consisting mainly of clams, oysters and mollusks. The green crab is a highly fecund species; a female crab can produce over 185,000 eggs in one clutch. Green crabs are also able to tolerate a relatively wide range of temperature and salinity conditions. These characteristics, along with a lack of natural predators, have allowed green crabs to successfully and rapidly colonize along the New England coastline. They remain abundant in the near shore subtidal habitats of New Hampshire. Green crabs compete with native flora and fauna for food and habitat, and are therefore harmful to local marine ecosystems. They have had a severely detrimental impact on New England fisheries due to their large-scale predation. Green crabs are principally blamed for the collapse of Maines soft shell clam industry, as well as the depletion of various estuarine fish populations. Additionally, their foraging and burrowing activity has done particular damage to eelgrass beds. Eelgrass communities provide an essential habitat and nursery ground for a variety of organisms, including those of commercial importance. Eelgrass also has vital ecological functions such as sediment stabilization and estuarine water purification. In order to maintain the integrity of New England estuaries, it is necessary to restore eelgrass beds and restock populations of organisms that have declined due to green crab predation and activity. However, these endeavors prove to be ineffective if abundance and distribution of green crabs is poorly understood. Restocking target species in an area that has heavy crab density would likely result in rapid eradication of the newly-restored species, rendering the project a waste of time and money.