A previously unknown field of endangered Staghorn coral has been found in Florida waters by scuba divers belonging to the non-profit group Palm Beach County Reef Rescue.

“We’ve found the largest field (of the coral) in the county,” says Reef Rescue’s director Ed Tichenor. “We’re really surprised by this.”

The field, which is located roughly a mile east of Palm Beach island, is significant since Palm Beach town officials have objected to federal protection of the area.

Last year, the National Marine Fisheries Service designated roughly 1,300 square miles of ocean floor – ranging from the Florida Key to the Boynton Beach Inlet – as critical habitat for staghorn. This prompted the Palm Beach County Reef Rescue to petition the government to extend the protected area northwards to the Lake Worth Inlet, thereby including the coast off Palm Beach.

The Palm Beach County Reef Rescue estimates the newfound staghorn field to be between 100 and 300 feet long.

“I was expecting to see it but not as much,” said Connie Gasque, a Palm Beach resident who led the dive group. “My reaction was ‘Wow!

Everywhere you looked, there it was.”

Before this discovery, only small pockets of staghorn coral was known to exist in the waters off Palm Beach.

Palm Beach County Reef Rescue now hopes that the discovery will convince the National Marine Fisheries Service to include the region in the protected coral zone.

What is Staghorn?

Staghorn (Acropora cervicornis) is a branching coral that can reach a length of up to 2 meters (almost 7 feet). It is the fastest growing species of all West Atlantic corals and can grow 10-20 cm per year in favourable conditions. The natural range for Staghorn coral stretches from Florida, USA through the Bahamas and the Carribbean Sea, down to Venezuela in South America.

Acropora cervicornis was placed on the U.S. Endangered Species List in 2006, and it is also listed as Critically Endangered on the IUCN Red List of Threatened Species.

According to the U.S. National Oceanic and Atmospheric Administration, staghorn is not found north of Boca Raton.

Rare coral species may be saving themselves from extinction by hybridising with other coral species, says Australian scientist Zoe Richards. Richards and his colleagues have studied 14 rare[1] and eight common coral species of the genus Acropora in the Indo-Pacific.

In order to find out more about hybridisation among corals, the team did a phylogenetic analysis using the highly polymorphic single-copy nuclear Pax-C 46/47 intron and the mitochondrial DNA (mtDNA) control region as markers.

The analysis showed that many of the rare species are polyphyletic for both Pax-C and mitochondrial phylogenies, and this is seen as a clear sign of interspecific hybridisation.

The results of the study “Some rare Indo-Pacific coral species are probable hybrids” by Richards, Oppen, Wallace, Willis and Miller were published in a recent issue of the journal PLoS ONE[2].

In their paper, the authors explain how “[t]he results presented here imply that a number of rare Indo-Pacific Acropora species are the products of recent hybridisation events, and highlight the significance of hybridisation in coral diversification. Whether these species have hybrid origins or have evolved and then hybridised in the absence of conspecific gametes remains to be elucidated.”

“In summary, although it has often been assumed that small populations have a decreased potential for adaptation, our analyses imply that some rare acroporid corals may actually have increased adaptive potential as a consequence of introgressive hybridisation, and therefore may be less vulnerable to extinction than has been assumed.”