May. 17, 2012

Skeleton Shrimp!

by Coastal Studies for Girls

Click to enlarge images
by Shauna, 10th Grade, Coastal Studies for Girls
Recently, the students of Coastal Studies for Girls, our marine science teacher, and one of our resident assistants visited the Bowdoin College Marine Laboratory. Upon walking through the doors of the little building hidden in the woods, we were greeted with multiple touch tanks containing so many sea creatures. There were sea stars, sea squirts, hermit crabs, sea anemones, sea cucumbers, and brittle stars, just to name a few. We were allowed to ask questions about the marine life, as well as to pick them up and feel them.
The two women who were there were Dr. Amy Johnson, a Biology professor and director of the Marine lab, and Tamara Perreault, who is an undergraduate student there. Tamara was working on her very cool experiments on Harmothoe imbricara -- more commonly known as the fifteen-scaled worm -- which glow and flash their own light when threatened.
One of my personal favorite species in the touch tanks was the Skeleton Shrimp, or Caprella sp. From a distance, they look like little pieces of grass, but once you get closer, they look to me like those little worm aliens from the first Men in Black movie.
With my hands in the tank, I placed a couple of Caprella on my fingers and they began clinging to me right away, swaying back and forth with the water. They were in huge packs of perhaps a couple hundred or more. There were so many together that they looked almost like one large organism.
In the video above, a skeleton shrimp female oxygenates her eggs in her red polka-dotted marsupium.
There are several species of skeleton shrimp in the coast of Maine, and even more around the world. We think the species we observed belonged to the genus Caprella. Despite their name, the skeleton shrimp aren’t exactly “shrimp”. The skeleton shrimp and your average cocktail shrimp are both crustaceans, but the skeleton shrimp are classified in a different order than the shrimp we eat.
Skeleton shrimp are invertebrates, meaning they don’t have a spine, and they can grow to be up to 4 cm in length. They can be found in the low intertidal zone and subtidal waters in bays. Skeleton Shrimp eat microscopic plants and filtered food particles.
Skeleton shrimp are pretty odd creatures. Sometimes after mating, the female will kill the male, although the reason is still unknown. They move by bending and straightening their bodies, propelling themselves through the water in small, jerky movements.
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