Global coral bleaching will degrade local reefs

| 14/05/2024 | 20 Comments
Bleaching at Spotts Reef taken in October 2023 (photo credit: DoE)

(CNS): The Cayman Islands is facing the possibility of further degradation of its reefs as another coral bleaching event is impacting reefs around the world this year. According to experts at the Department of Environment, our coral reefs are slowly dying, and every year we can expect fewer of them to bounce back for another season. Like many countries in this region, The Cayman Islands is under a NOAA bleach watch as the reefs become evermore vulnerable to a warming planet.

“As sea temperatures have steadily risen over the past several decades, our reefs have undergone repeated stressors, making them increasingly vulnerable to diseases like stoney coral tissue loss disease,” DoE Deputy Director Tim Austin told CNS.

“The bleaching event last year and the one expected this summer are evidence we have likely moved into a more consistent pattern of ocean warming, so we can really only expect our reefs to become continually more vulnerable as they simply do not have enough time to recover in any meaningful way between events. The result is, and will be, mass reef degradation over time,” he added.

Austin explained that bleaching events might be more significant in some years than others, but over time, coral cover will continue to disappear, as it has been doing over the last few decades.

“This summer, we are likely to see another bleaching event where the vast majority of visible corals are presenting as fully bleached,” he said in response to questions. “As sea temps recover, it is quite possible that many bleached corals will not regain their natural colour or health as quickly, if at all.”

Austin explained that as the seas warm and essential grazers like sea urchins and reef fish populations fall prey to disease and over-fishing, algae levels increase and literally suffocate the corals. “Long-term monitoring has shown consistent degradation of coral cover and general health over the last 25 years.”

With local reefs already suffering from SCTLD and record-breaking ocean temperatures, this bleaching event will add to the stress on local reefs. Dr Croy McCoy, the DoE Marine Resource Unit manager, said much is still unknown about this disease, but the more stress there is on the reef, the more vulnerable it is.

“It is likely a safe assumption that a coral head infected with SCTLD would be more susceptible to bleaching simply because it’s already in a weakened state,” he said. “Conversely, SCTLD would actually be somewhat mitigated in a bleached coral since the disease targets the zooxanthellae algae which the bleaching would already have removed from the coral.”

The marine expert said that work is being conducted here in Cayman and around the world in coral scientific communities to develop coral nurseries and coral banks. The goal is to breed corals resilient to the stressors of climate change and eventually attempt to repopulate the reefs to help slow down degradation and build resilience.

“Though extremely costly, ambitious and incredibly challenged on many levels, there are coral labs around the world showing signs of growth success,” he said. “The Foster’s Group has generously donated two coral spawning labs which allow DoE’s marine research unit to breed and grow corals in a lab environment and also expose them to a number of variables to research the effects.”

But even the most optimum coral species for lab work grow only a centimetre or two per year, so the DoE is hoping to secure support to expand the lab to include a larger, open-air coral-growing facility capable of growing thousands of corals at a time for two to five years before planting them back out on the reef.

“This would also allow us to continue to test their resiliency under various lighting, chemistry and temperature combinations and select the best ones for reintroduction into the wild,” McCoy said. “While growing thousands of genetically resilient corals in large outdoor fields is at the forefront of coral research technology, we would be remiss to forget that global emissions of greenhouse gases, especially CO₂, are the actual underlying cause of our warming planet.”

McCoy pointed out that Cayman remains the greatest contributor of greenhouse gas emissions in the region despite being one of the smallest countries.

“Like the rest of the world, we too have a responsibility to not only reduce our carbon footprint but also to protect the elements that provide resiliency, including our mangrove forests, seagrass beds and indeed coral reefs from human impacts like habitat loss, coastal development and dredging, and nutrient runoff,” he added.

The Cayman Islands are the tops of underwater mountains, and our coastal shelf is narrow, but the ecosystems run vertically for thousands of meters around all three islands. “Cayman is quite literally built on and from coral reefs, which are essentially dying before our eyes,” McCoy said.

Austin said that Cayman needs to reduce carbon emission outputs, employ more comprehensive air and water quality standards, and incorporate sustainable design practices into our building and development models.

He said that Cayman could still prepare for some of the challenges climate change will bring by investing in coral nurseries, maintaining the immeasurable benefits of our mangrove wetlands, dry forests and active beaches, and respecting current and future regulations around native species conservation.

“The challenges remain regardless. It is simply a matter of how we choose to act now, knowing what we know,” Austin added.

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Category: Marine Environment, Science & Nature

Comments (20)

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  1. Anonymous says:

    Why haven’t we banned sunscreen that isn’t reef safe from being sold on island? It’s not the fix but it is a start.

  2. Anonymous says:

    Not to mention the run-off from all of the deep wells.

  3. Sad says:

    There is a coral structure in front of Sunset Cove. I have swam there the past 37 years. It was BEAUTIFUL! Large groupings of Blue Tangs, health corals, well beyond the shore groynes.

    Last year it all died. The juvenile corals are all gone (January 2024). I have seen small fishing boats throw out anchors last year on top of the reef (Locals, sorry), as well as small charter snorkel boats (again, probably locals). Then there are the jet skis that have no interest in respecting the 150′ buoy markers. And obviously no enforcement of regulations. So between environmental and self-inflicted harm… the reef is gone. A cherished memory of 37 years destroyed.

  4. Anonymous says:

    Sadly, new divers to the island think they are seeing an unbelievable underwater world, but those of us who know the benchmark from 20-30 years ago, we understand that the marine environment is past the tipping point. Cayman is well down an ugly road, and it doesn’t resolve over night.

  5. Radio Rich says:

    I came to GC in 2005 and stayed on an off for seven years, can’t imagine what the diving off SMB is like now. Fairly recently I worked in Provo TCI (dive instructor aswell). The reef there is completely destroyed, no fish, no coral but go to West Caicos 90 mins away by boat where there are no resorts or humans and it’s beautiful, some of the biggest barrel sponges I’ve ever seen. Worked in BVI for a few years, those reefs are toast, mostly destroyed. Now I work the winters in Saba, 100 miles away from BVI and the diving is pretty good, not perfect though. We only get roughly 200 tourists a week and there’s one dive company so it’s manageable. Too many humans is the problem. I remember talking to an old timer who emigrated from Scotland to GC back in the 70’s. He would tell me he and his family would go out in their boat to North Sound and the place was covered with conch and sand dollars everywhere. No humans = happy planet. Where we are now = dead planet.

  6. Anonymous says:

    we are past the tipping point for global warming….
    bottom line if you want the most healthy reefs as possible…ban the dive industry and local fishing.

    • Anonymous says:

      Nonsense. The industry that does the most harm to our reefs is consistently the cruise industry. Start there, then we can assess if we need to take more drastic action.

  7. Anonymous says:

    Who cares about our beaches and seas; let’s build more concrete monstrosities and they will come!

    The Island that tourism forgot soon reach!

  8. Anonymous says:

    What exactly can he do to revive the reefs?

    • Anonymous says:

      Eradicate all humans.

      I’m not up for this, and wouldn’t promote anyone killing themselves to save the reef, but that’s the only thing that can save it.

      • Radio Rich says:

        Sounds extreme but you’re right. If there were no humans the planet would flourish, we’re really like an untreated tumor, ever expanding and replicating destroying everything around us.

  9. Anonymous says:

    I came to the islands as a dive instructor 18 years ago. I recall even then I was shocked on arrival to see the poor state of the reefs here when I had heard so much about how good the diving was. Sure, the water was clear but the reefs were mostly dead even then.
    Now add in the devastation caused by lionfish, some damage by a couple of big storms, years of rising sea temperatures and pollution….and now the reefs here look worse than ever. I could cry when I see how they have changed so much even in the last 18 years.
    Soon people will not pay the expensive prices to come here and dive on dead reefs. With our underwater environment being such a big draw for tourism, once it’s gone, what will we have left?

  10. Anonymous says:

    Linked to Population expansion Cayman leaching of waste in to waters and Global warming deniers touting their pure bullshit.We need to get rid them first.

  11. Anonymous says:

    As corals and scuba diving are a large part of our tourism product, what does the Tourism Minister have to say is the plan to prevent the bleaching as much as possible to save the diving jobs?

    Or does his plan only involve Government giving stipends to the diving companies and staff when things get worse than today?

    • Coral Reefer says:

      Come on mate, no one can stop the inevitable. He is not to blame nor responsible for the success or failure of private industry.

      Time to pivot.

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