A close-up of a staghorn coral (Acropora cervicornis) branch tip. Note the healthy coral polyp extension.

This past Saturday I took my friend Jeremy (of coralpedia.org) and his wife on a shore dive off Fort Lauderdale Beach. I had heard rumors that decent stands of the endangered staghorn coral (Acropora cervicornis) were abundant in this area. Despite (relatively) poor visibility, we found these rumors to be correct. Acropora cervicornis was one of, if not the most, common stony corals only 250-350 meters offshore this popular sunbathing mecca in only 6-7 meters of water. It is amazing to see how even a small ‘bush’ of A. cervicornis can attract dozens of small fish seeking refuge amongst its branches. It is clear that the widespread die-off of this single species has had a detrimental impact on the entire ecosystem of the Florida’s coral reefs. I can only imagine what the reefs in the Florida Keys were like 30 years ago, as today most are just lumpy humps of rock dominated by massive coral heads, gorgonians, and macroalgae. The interstices of A. cervicornis branches provides a habitat that is unmatched. Seeing an abundance of A. cervicornis so close to shore in Fort Lauderdale is encouraging.

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The spongy decorator crab (Marcocoeloma trispinosum) takes expert care in snipping off pieces of living sponge and attaching them to its carapace (exoskeleton shell). Detritus and debris are added for additional camouflaging effect. This particular crab has taken the decoration to the next level by including some spectacular zoanthids (Zoanthus sp.) into its design. As you can imagine, the crab was living amongst a colony of the same zoanthid morph, rendering it nearly impossible to detect. Furthermore, decorator crabs move very slowly and deliberately, quite unlike the unpredictable scurry of most other crabs. The purposeful addition of camouflaging marine life to the body of this crab highlights the evolution and subconscious intelligence of  ‘tool-use’ at such a ‘primitive’ level in the animal kingdom.