ELKHORN CORAL, ABACO BAHAMAS (DORIAN UPDATE)


Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

ELKHORN CORAL, ABACO BAHAMAS (DORIAN UPDATE)

Elkhorn coral (Acropora palmata) is a widespread reef coral, an unmistakeable species with large branches that resemble elk antlers. The dense growths create an ideal shady habitat for many reef creatures. These include reef fishes of all shapes and sizes, lobsters, shrimps and many more besides. Some of these are essential for the wellbeing of the reef and also its denizens.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

GOOD POST-DORIAN NEWS ABOUT ABACORAL

A recent report from FRIENDS OF THE ENVIRONMENT brings encouraging news about the reefs of  Abaco post-hurricane, and an indication of the resilience of the coral to extreme conditions (with one exception for a reef too close to the shore to avoid damage from debris).

Shortly before Dorian hit, The Perry Institute for Marine Science and its partners surveyed reefs across Grand Bahama and Abaco to assess their health. Following Dorian, they were able to reassess these areas and the impact of the hurricane. Over the 370 miles that the surveys covered, minimal damage was found on the majority of reefs. Unfortunately Mermaid Reef, where FRIENDS does most of our educational field trips, sustained extensive damage due to debris from its close proximity to the shoreline. We are looking into how we can help with logistics to get the debris removed, and hopefully the recovery will begin soon.

Elkhorn Coral, Pelican Cays, Abaco Bahamas (Friends of the Environment)

Elkhorn coral standing strong post-Dorian at Sandy Cay Reef, Pelican Shores, Abaco

The scientists were also able to visit four of the Reef Rescue Network’s coral nurseries and assess out-planted corals in national parks in both Grand Bahama and Abaco. The great news is that all of the corals on these nurseries survived the storm and will be used to support reef restoration. Also from the surveys, it appears that our offshore reefs around Abaco sustained minimal damage, including Sandy Cay Reef in Pelican Cays Land and Sea Park (pictured above). This gives us hope for the recovery of our oceans post-Dorian and proves how resilient these amazing ecosystems are.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

Examples of species vital for healthy corals include several types of PARROTFISH, the colourful and voracious herbivores that spend most of their time eating algae off the coral reefs using their beak-like teeth. This algal diet is digested, and the remains excreted as sand. Tread with care on your favourite beach; in part at least, it will consist of parrotfish poop.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

Other vital reef species living in the shelter of elkhorn and other corals are the CLEANERS, little fish and shrimps that cater for the wellbeing and grooming of large and even predatory fishes. Gobies, wrasse, Pedersen shrimps and many others pick dead skin and parasites from the ‘client’ fish including their gills, and even from between the teeth of predators. This service is an excellent example of MUTUALISM, a symbiotic relationship in which both parties benefit: close grooming in return for rich pickings of food.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

VULNERABILITY TO OFFICIALLY NON-EXISTENT CLIMATE CRISIS

Formally abundant, over just a couple of decades elkhorn coral has been massively affected by [climate change, human activity and habitat destruction] inexplicable natural attrition in many areas. One cause of decline that is incontrovertible is damage from storms, which are empirically increasing in both frequency and intensity, though apparently for no known reason.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

Physical damage to corals may seriously impact on reproductive success; elkhorn coral is no exception. The effects of a reduction of reef fertility are compounded by the fact that natural recovery is in any case inevitably a slow process. The worse the problem gets, the harder it becomes even to survive let alone recover. 

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

SO HOW DOES ELKHORN CORAL REPRODUCE?

There are two types of reproduction, which one might call asexual and sexual:

  1. Elkhorn coral reproduction occurs when a branch breaks off and attaches to the substrate, forming a the start of a new colony. This process is known as fragmentation and accounts for roughly half of coral spread. Considerable success is being achieved now with many coral species by in effect farming fragments and cloning colonies (see above, Reef Rescue Network’s coral nurseries)
  2. Sexual reproduction occurs once a year in August or September, when coral colonies release millions of gametes by broadcast spawning (there’s much more to be said on this interesting topic, and one day I will)

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

THE FEATURED PHOTOGRAPHS

You may have wondered in which healthily coral-infested waters these superb elkhorn coral photographs were taken. Did I perhaps source them from a National Geographic coral reef special edition? In fact, every image featured was obtained among the reefs of Abaco.

All except the recent Perry Institute / Friends of the Environment photo were taken by Melinda Rogers of Dive Abaco, Marsh Harbour. The long-established and highly regarded Dive Shop she and her husband Keith run was obliterated (see above) less than 3 months ago by Hurricane Dorian, along with most of the rest of the town. It’s a pleasure to be able to showcase these images taken in sunnier times.

Elkhorn Coral, Abaco Bahamas (Melinda Rogers / Dive Abaco)

ONE GOOD INTERN DESERVES ANOTHER (Part 1)


Coral reef research, Australia (Oscar Ward)

ONE GOOD INTERN DESERVES ANOTHER (Part 1)

Four years ago a young English friend of ours, Oscar Ward, was lucky enough to be offered an internship with the Bahamas Marine Mammal Research Organisation (BMMRO). At the time, he was post-school, and waiting to start a degree course in marine biology at university. He had no practical experience at all, so he had to progress from the menial tasks (scraping barnacles off the bottom of the research boat) to the more adventurous (whale poop-scooping) to the scholarly (collection and analysis of samples and data, including audio file matching of whale calls for identification). The need for hard work, concentration and accuracy were made clear from the outset… and as you will see, Oscar’s short internship has stood him in very good stead during his university course.

Oscar weekending at Gilpin Point – self-sufficientBMMRO Internship - weekend off (Oscar Ward)

From a promising start on Abaco, and with 2 year’s study behind him, Oscar is currently spending the 3rd year of his 4-year course in Australia, working with The Australian Institute of Marine Science. He has been involved in a number of complex projects focussed on corals and reef life – as we all know, a matter of huge concern – and the projections for the future of the reef systems in a time of warming seas and raised acid levels. Oscar also assists PhD students, for example examining the damaging effects of parasitic worms on coral; and the effect of changing light conditions on corals.

Nurse Sharks, Great Barrier Reef (Oscar Ward)

Much of Oscar’s time has been spent doing fieldwork. Often he is at sea, monitoring and collecting samples in the Southern Great Barrier Reef, diving two or three times a day. This work is often carried out in restricted or preservation zones, and with ever-present manta rays, sharks and sea turtles around him.

Manta Ray, Great Barrier Reef (Oscar Ward)

Right now Oscar is involved with the investigations into the recent bleaching events, work that is at the forefront of serious concern for the GBR and far beyond. I have recently corresponded with him – he has definitely not forgotten that his grounding for the fieldwork and studies that he is engaged in – and very likely his career – came from his time on Abaco and the lessons he learned during his time with the BMMRO at Sandy Point.  (In part 2: another good intern, currently at Sandy Point)

Coral reef research, Australia (Oscar Ward)

All photos: Oscar Ward (the header image is taken from a research vessel – no idea how, maybe a drone with fish-eye lens?)

UNDERWATER BAHAMAS: REEF GARDENS (2) – CORALS


Purple Seafan Coral ©Melinda Riger @GBS

UNDERWATER REEF GARDENS IN THE BAHAMAS (2): CORALS

This is part 2 of a series that started out HERE with a selection of anemones, basket stars and Christmas tree worms. The images below show a wide variety of corals. In among them are also sponges and anemones. These photos are evidence of a healthy reef environment in the waters of the northern Bahamas. Abaco’s coral reef is the third largest barrier reef in the world (yes, I hear you – the Great Barrier… And the second is???), providing wonderful and accessible diving / snorkelling opportunities. However, monitoring shows that the incidence of coral bleaching and disease is increasing in the Bahamas, as elsewhere in the world.  It’s a sobering thought that your grandchildren may never swim in an environment with any of the living corals shown below…

Corals ©Melinda Riger @ G B ScubaCoral ©Melida Riger @ G B  ScubaCoral ©Melinda Riger @ G B Scuba 1Coral ©Melinda Riger @ G B Scuba 2Coral ©Melinda Riger @GBSImage Credits: ©Melinda Riger @ Grand Bahama Scuba