Biorock heals hurricane damaged Jamaican corals

October 31, 2021

Thomas J. F. Goreau
Thomas P. Sarkisian
Sharren Robinson

Global Coral Reef Alliance

The record long and severe 2020 Hurricane Season spawned two category 5 hurricanes just south of Jamaica, Hurricanes Eta and Iota, after the normal hurricane season had ended. These caused devastating damage in Nicaragua, Honduras, and all the islands of the southwest Caribbean, especially San Andres, Old Providence, the Corn Islands, and the Miskito Cays. Jamaica was not spared, waves 5 meters tall battered southwest Jamaica, breaking and smashing the few corals left on the reef.

As soon as the waves had calmed down so it was safe to dive we collected live broken corals lying upside down on sand, mud, and rock and transplanted them to Biorock reefs in December 2020. The major breakage found was to elkhorn coral, which used to provide nearly 100% live coral cover around Jamaica, but which has become very rare following large-scale death from dredging, hurricanes, diseases, high temperature bleaching, coral eating worms and snails, pollution-caused algae overgrowth, etc.

In the past decade there has been sporadic new settlement of isolated elkhorn colonies in Southwest Jamaica. These were heavily damaged by hurricane waves, branches were broken off and whole colonies flipped upside down. All had badly damaged tissue releasing large amounts of mucus. Most had been sitting upside down on rock or buried under sand, so much tissue was rotting, releasing slimy mucus. Most surviving coral tissue on undersides of fragments bleached and died, and some had only very small patches of remaining living tissue in pale and poor condition.

Corals found naturally broken nearby were mainly elkhorn (Acropora palmata), but a few other corals were found and rescued, including staghorn (Acropora cervicornis), finger coral (Porites porites), brain corals (Pseudodiploria strigosa), and other species were rehabilitated by Biorock electrotherapy. Photographs in this report taken by Sharren Robinson show results 10 months after corals were rescued.

Results have been spectacularly successful. The elkhorn fragments have grown over and right around the steel structure and are starting to form prolific new branches. Small bleached and dying patches of tissue are now dark golden brown and expanding, overgrowing dead skeleton. Staghorn fragments have formed new branches with especially large growing tips. A large brain coral, hundreds of years old, whose base was broken in the first hurricane, and rolled around upside down on rock and sand in both hurricanes for nearly a month before we could rescue it. At that point most living tissue on the top was scraped off, the skeleton was abraded and gouged, and the edge of the tissue was rotting. 10 months later new dark brown coral tissue had nearly completely overgrown the damaged area. This shows exceptional healing, a coral in this condition would normally get infections that would kill the surviving tissue.

Our results show that Biorock electro-therapy heals severely hurricane damaged coral fragments. It also regenerates lost ecosystem benefits of shore protection, fisheries, biodiversity, and ecotourism. Conventionally fragmented corals die whenever the water gets too rough, hot, muddy, or polluted (Foo & Asner, 2021), conditions that corals on Biorock survive due to their superior resistance to extreme stresses (Goreau, 2021). Biorock reefs survived category 5 hurricanes without damage in Grand Turk, and Saint Barthelemy. Biorock is the method of choice in regenerating reefs damaged by hurricanes, typhoons, tsunamis, and other extreme storms, and those affected by global warming and sea-level rise.

Biorock reef regeneration was invented in Jamaica in 1987. This is the only project now underway in Jamaica. We propose to work with Jamaican Fish Sanctuaries and Marine Protected Areas to expand Biorock reef regeneration around the island of its birth!