Giant barrel sponge

Photo: Mike Westerfield · © all rights reserved

Giant barrel sponges are among the largest and longest-lived invertebrates on Caribbean reefs, with some individuals estimated to be over 2000 years old. On the North Wall they grow to 2 metres in diameter, providing shelter for gobies, brittle stars, and shrimp in their central osculum. They are filter feeders that process enormous volumes of water daily, playing a fundamental role in nutrient cycling and water clarity on the reef.