Giant barrel sponge

Photo: Thibaud Rossard · CC BY-NC

Giant barrel sponges are the largest sponge species in the Caribbean and among the longest-lived animals on coral reefs, with some individuals estimated to be over 2000 years old based on growth rate studies. A single large barrel sponge can filter more than 90 litres of water per minute, extracting bacteria and dissolved organic matter — making them a critical water-quality mechanism on healthy reefs. They provide habitat for shrimps, small gobies, and occasional hawksbill turtles that feed on them. Their populations are considered a reef health indicator: dense barrel sponge assemblages like those at Le Cap indicate a nutrient-rich, productive system.