Figure 1. Percentage growth of branching sponge pieces (change in wet mass) 287 days after attachment inside and outside of predator-excluding cages at 15 and 30 m depth on Conch Reef, Florida.

A: Callyspongia armigera and B: Iotrochota birotulata lack chemical defenses, while C: Amphimedon compressa and D: Aplysina cauliformis contain alkaloids that deter fish predators, represented by a portion of the chemical structure of amphitoxin for the former and aeroplysinin-1 for the latter. Surviving number of 20 replicates is shown for each bar, error bars are standard error. Statistical analyses were performed on transformed data (growth index). An asterisk indicates a significant difference in growth inside vs. outside cages (p<0.01).