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Exotic or Introduced Species

Exotic species are organisms that live within an area that is not native to their original habitat and has been either accidentally or deliberately moved by humans. It may not seem like a big problem but over time the introduced species can change the whole structure of the ecosystem it lives in.

Exotic species tend to be organisms that are able to reproduce rapidly and thrive in different habitats very easily. With the population of the species increasing rapidly it takes away food, shelter and space from the native species that have been living in their respected habitats throughout.

A few of the introduced species may seem as though that they are native because they have been around for so long. Three introduced species that live within the estuary we have here in our immediate area are the common periwinkle, the green crab and the Asian shore crab.

The common periwinkle was introduced on the New England coast in the 1870’s by the shipping routes from Europe. By the late 1880’s, they were found as far south as Cape May, New Jersey. It was led to believe that they were brought over from the hulls of the ships through the trade routes.

The green crabs originally inhabited the coasts of the North and Baltic Seas and now are distributed across South Africa, Australia, and both coasts of North America. These crustaceans are very highly adaptable when it comes to changing environments. They can withstand changes in temperature and salinity levels, and produce an incredible amount of eggs at one time, 200,000! These crabs pose a threat to shore birds and fish populations because of their similar diets, which can alter the food web within their ecosystem.

The Asian shore crab’s original habitat is in the western Pacific Ocean waters’ along Russia, China, Korea and Japan’s coastline. They were first found along the North American coastline in New Jersey in 1988, and now can be found as far north as Maine to as far south as North Carolina. Again, it is believed that they were introduced from the water discharge within the ballasts of the shipping barges. The Asian shore crab reproduces twice as much as the native crabs and within one clutch can produce 50,000 eggs. They are highly adaptable to environmental conditions and eat a wide array of food that can greatly affect the food web within their habitat.

Scientists are trying to come up with ways to rectify the distribution of introduced species but with these organisms ability to reproduce quickly and their high adaptablity, it is a tough fight to win. Some scientists have come up with ways to capture some of the species and have even thought of introducing new species to hopefully lessen the population’s distribution, but that may cause more of a headache down the line.

Next time you are at the beach, salt marsh or estuary look for these species; they are probably fairly easy to find. Know that they are introduced or exotic species and look for the native species to give them the extra support they need! Goooooooooooooo, native!!!

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