What is this Marine Organism?

Dr. K. was recently asked a question by Dan Stahl of Outside North Shore Ltd. about an otherworldly looking creature on the bottom of his boat in Northport, NY.  With Halloween around the corner, we thought it would be a good time to share one of the stranger looking denizens of Long Island Sound. Bonus points for anyone who sends in a picture of themselves dressed as a Caprellid!

Q: I just pulled my dinghy out of the Sound and all of these were all over the bottom of the boat.  What is it? 

Photo Credit: Dan Stahl


Dr. K:

Thanks for your question – it’s very timely given the season! What you have found is a caprellid amphipod, a type of marine crustacean commonly referred to as a skeleton shrimp (Caprella penantis). They are colonial ambush predators— that is they live in colonies that love to attach to substrate, like boat bottoms, in areas of high current, and then they wait for prey to float by, and grab it.

I see them a lot when SCUBA diving to do repairs or maintenance on water quality buoys as they love to colonize the lines and cables. My first thought is almost always “If this thing were a hundred times bigger it could have come straight out of an Aliens movie!”

Credit: Howard M. Weiss, Ph.D., Project Oceanology, Marine Animals of Southern New England and New York, 1995


Thank you for sending your question in and have a Happy Halloween!

 Jason Krumholz, aka Dr., K, is the NOAA liaison to EPA’s Long Island Sound Office. Krumholz received his doctorate in oceanography at the University of Rhode Island Graduate School of Oceanography.


Have a Sound Health question?


Send an e-mail to Jason Krumholz.. Dr. Krumholz  is a marine scientist working as the NOAA liaison to the EPA Long Island Sound Office. View more of Dr. K’s questions and answers on the Ask Dr. K blog.



Editor’s Note: The opinions expressed in this blog are those of the author. They do not reflect EPA or NOAA policy, endorsement, or action, and EPA or NOAA do not verify the accuracy or science of the contents of the blog.


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