Clumps on Island Beaches

The high winds the first weekend of November 2010 brought in what appeared to be tarballs to Sanibel beaches.  Marine Lab Director Loren Coen and Research Scientist Rick Bartleson, along with James Evans from the City of Sanibel, identified them as tunicates, which also washed up this past summer. 


Black colonial tunicates washed up on Sanibel beaches, along with pen shells, the weekend of November 6, 2010.

This past summer

Over the summer, clumps resembling tarballs were found on Fort Myers Beach, on Lighthouse Beach on Sanibel and on Cayo Costa.   Click here for more info on the Deepwater Horizon spill.

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Marine Lab Research Scientists Eric Milbrandt and Rick Bartleson  confirmed from samples that they are not tarballs.  The larger Fort Myers Beach clumps are black colonial tunicates. Tunicate expert Gretchen Lambert identified the genus as Eudistoma, based on a photograph.  In addition, black solitary tunicates have also been found on island beaches.


Above:  Black colonial tunicates of the genus Eudistoma.  Photo by Rick Bartleson.



The smaller clumps found on Sanibel this past week are filamentous blue-green algae broken off from underwater algal mats.
Photo above left from the City of Sanibel; above right by Rick Bartleson.


Black solitary tunicates have also been found on island beaches.  When they wash up, the siphon is not extended, so the tunicate looks like a shiny, slimy irregular oval.  Photo from the Smithsonian Marine Station in Fort Pierce.

Updated 6/3/10