Thursday, July 31, 2014

Assignment 1, Part 2: Lovell's Island

After all the fish were caught, Captain Charlie Dropped us off on Lovell Island for an exploratory walk among the tidal pools. We observed a variety of life hidden among the rocks in the tide pools including common periwinkles, invasive asian shore crabs, barnacles, and hermit crabs.

The Common Periwinkle Littorina littorea, is a small marine snail that can be found along the East Coast from Nova Scotia to Maryland. The L. littorea originated in Europe but was introduced to the East Coast in the 1800’s and are thought to have made the journey from Western Europe attached to rocks used as ballast in ships coming across the Atlantic. Periwinkles have a stout spiral shell, usually in various shades of gray and can grow up to around 1.5 inches. Periwinkles can be found along the shore on rocks or some muddy bottoms, making them an easy target for shore birds which are their primary predator.

The Editors of Encyclopædia Britannica. "Periwinkle." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 30 July 2014.

"Periwinkle." Eat The Invaders RSS. N.p., 28 June 2012. Web. 30 July 2014.

Praying Mantis

Invasive Asian Shore Crab Hemigrapsus sanguineus is a small species of crab that is indigenous to the pacific coast of Asia. It was first observed on the east coast of the United State in the late 1900s and is now found along the coast from the Carolinas to Maine. Similarly to the Periwinkles, the Asian shore crab is thought to have made its way to the east coast via the ballast of ships. The crab is found along intertidal zones, and can easily be spotted collecting under rocks. The crabs are a direct competitor for food for native crab species and leading to the decline of many.

Benson, Amy. "Asian Shore Crab." Asian Shore Crab. U.S. Geological Survey, 11 July 2013. Web. 30 July 2014.

Down Under Barnacle Elminius modestus is an invasive crustacean that originates from Australia and New Zealand, making its way across the globe by attaching to the hulls of ships. It was introduced to Europe and is anticipated to appear along the east coast. Barnacles are made up of calcareous plates that surround the soft parts that are cemented down to rocks, a host species, dock pilings, or the hulls of ships. Barnacles trap their microscopic food via feathery organs called cirri.

"Barnacle (crustacean)." Encyclopedia Britannica Online. Encyclopedia Britannica, 10 Mar. 2014. Web. 30 July 2014.

"Issg Database: Ecology of Elminius Modestus." Issg Database: Ecology of Elminius Modestus. Global Invasive Species Database, 8 June 2010. Web. 30 July 2014.

Hermit Crabs have no shell of their own, but rather use the empty shells of other crustaceans such as the periwinkle, and must transfer to larger shells as they grow. The availability of empty shells can create competition amongst the hermit crabs.

Encyclopædia Britannica. "Hermit Crab (crustacean)."Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 30 July 2014

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