[Coral-List] Giant barrel sponges taking over Florida's reefs!

Pawlik, Joseph pawlikj at uncw.edu
Tue Sep 1 10:45:15 EDT 2015

Greetings, Colleagues,

In a 12-year study just published in the Journal of Experimental Marine Biology and Ecology, we report that populations of giant barrel sponges have increased by 122% since 2000 on Conch Reef, off the coast of Key Largo, Florida. This adds to the growing evidence that sponges are becoming the dominant inhabitants of modern Caribbean reefs.  The article can be downloaded for free:


Giant barrel sponges (Xestospongia muta) are found throughout the Caribbean, and commonly grow to the size of an oil drum or larger. Called the "redwoods of the reef," these sponges can live to be hundreds, even thousands of years old, based on earlier growth studies conducted by the same first author, Dr. Steven McMurray.
A video tour of the plots on Conch Reef can be seen here: https://youtu.be/qdjhm7ojGJk
You can see how large these sponges get in this video from the Bahamas:

Not only are the numbers of giant barrel sponges increasing, so is their volume, with a 39% increase since 2000. On average, each square meter of Conch Reef now has about 2 liters of barrel sponge tissue on its surface, more than any other organism on the reef.  And the giant barrel sponge is only one of many species of sponges that populate Caribbean coral reefs.

Much of the increase in the numbers of giant barrel sponges was due to recruitment - the successful establishment of baby sponges. On some plots, the increase in the smallest-sized barrel sponges was over 600% for the period 2000-2012. And while the survival of larger barrel sponges was stable for the first half of this period, it increased during the second half, perhaps because of the absence of hurricanes over that time period.  When hurricanes pass over reefs, large sponges can be damaged and dislodged, often resulting in mortality.


Joseph R. Pawlik, Professor,
Dept. of Biology and Marine Biology
UNCW Center for Marine Science
5600 Marvin K Moss Lane
Wilmington, NC  28409
Office:(910)962-2377; Cell:(910)232-3579
Website: http://people.uncw.edu/pawlikj/index.html
PDFs: http://people.uncw.edu/pawlikj/pubs2.html
Video Channel: https://www.youtube.com/user/skndiver011

More information about the Coral-List mailing list