Nursery corals appear to have spawned ahead of schedule!


Eco Divers Reef Foundation 2018 Season Summary.

In 2016, we were allowed to harvest some small amounts of coral and place those small, finger sized pieces of coral into a nursery environment.  It was April and Summer would soon arrive bringing with it the first real trial of our nursery program design.  Coral Bleaching was found to occur across the world and 2016 has been marked as one of the most damaging years ever recorded for total coral lost to bleaching.  Caused by a simple mechanism of overheating, corals were exposed to fatal amounts of rising temperatures worldwide.  Here in Grand Cayman, we had a secret weapon to avoid the loss due to bleaching that might otherwise have ruined us in our first year.  Our nurseries were suspended in deep water.

We simply pulled them down a little deeper into the water and watched as our reefs bleached.  We read abut the bleaching elsewhere.  But our corals were safe, protected from the heat.  And they thrived.  They put on mass and spread and began growing together.  And for the next year, we faced storms and bleaching without incident.  During this time, we monitored and watched our corals.  More novelty than anything else.

However, by the Summer of 2017, our corals had grown into mature colonies.  They were so massive that additional floats were needed to prevent the nurseries from sinking to the bottom. That Summer, reports came across of nearby nursery corals spawning and we grinned as we spoke about how our own corals might have also spawned.  Not ever truly believing that there was a realistic chance they had.

During the following year, our program took on a new life.  Volunteers have joined us from all walks of life.  Caymanian and Expatriate diving together, focused on our program corals.  And we began to hear from our neighbors about the sudden appearances of Staghorn corals that had been absent for a decade or more.  The reality that our corals were already spawning became more likely and inspired us to push forward.

Our entire program is designed around the idea that our corals should spawn every year.  We never expected the nurseries to start before our proper outplanting program was underway, but the idea was the same.  Spawned corals provide a variety of genetics that offer not only increased resistance to bleaching and disease, but also a stronger foundation for long term survival overall than a reef populated with so many clones of one another taken from a single coral colony.

So after we wrapped up our outplanting program in 2017-2018, we decided to spend some quality time with our corals late at night in the middle of Summer.  Stories of other nurseries spawning had reached our ears all year long and we were determined to see ours spawn as well.  At 9:45 on August 28, they did.  Not a small spawn but instead a massive cloud of tiny white gamete packets released for around 15 minutes.

We had evidence that our corals have spawned in the Summer of 2018.  And we were pretty happy with ourselves.  We had researched and found that spacing our outplant sites within a mile and a half of each other would give us maximum dispersion rates for spawned corals based on our local terrain and currents.  We had reasoned that moving corals into deeper water was still allowing them to grow quickly and form massive structures.   Moving to these deeper sites prevented storms or bleaching from possibly killing our project corals in the upcoming years.

And then to wrap up all our final points of data, we needed to survey not only our outplanted sites, but the reef between those outplanted sites.  We counted each head of Staghorn coral we found the entirety of the dive between sites.  Some sites were close to 1500 meters apart.  When we looked at the maps we had created and where the corals are currently living on the reef we found some interesting results.

No Staghorn was found in water less than 28 ft deep.  The shallow, warm water is subjected to seasonal storms and was a harsh realm that resisted coral colonization.  Other species reside there, but no Staghorn.  However, we are finding all the way over the edge of the main wall down as deep as we are willing to dive, there is Staghorn.  Migrated by natural process into deep, safe waters.  Protected from the brutal changes of warming Seas and powerful storms.

We also realized that our nursery sites had indeed spawned at least once already.  Areas within 400 meters of our nursery sites were home to healthy, robust coral colonies.  We might have found 45 coral colonies on an entire 1500 meter dive and all but four or five would be within that dispersion arc of the nursery site.  Other areas without the nurseries were found to have similarly barren Staghorn coral counts.  The only sites with robust Staghorn are easily able to be attributed to the Nursery sites.

We are unable to say if this is from one or two years of spawning, but either would mean we now have a window into the future we can expect from each of our outplanted coral sites.  An arc or 400 meters spread from each site would expand upon itself each year and quickly fill in the spaces between sites with healthy coral cover.  There are some limits.  Shallow areas are unlikely to enjoy the robust recruitment of coral larvae we have seen on our primary reefs.  Surely some corals will settle and find a safe home, but that range appears to need specialized species and attention outside of the range of Staghorn corals.

Now we move forward into 2019.  We seek to expand our nurseries to include 10 total genotypes of coral and add those new genotypes to each of our existing six sites.  At the same time, we seek to expand our site selection to cover the entirety of the Seven Mile Beach area.  Carefully selected sites on the main reef could provide the same effective results that our NorthWest and SouthWest sites have enjoyed.

We anticipate that to spread coral evenly around the entirety of Grand Cayman might be as few as five total years of hard work.  The rewards of doing such could be priceless.  Coral degradation around the world is reported over and over.  Never is a victory spoken about.  And yet, here in the Cayman Islands we have the ideal formula for a victory of monumental proportions.  Able to rebuild the shattered morale of a world weary of hearing about loss.

To all of you who have joined us already, I thank you.  This is all thanks to the tireless work of our many volunteers and supporters.  And to everyone who would like to help us I offer an invitation.  Join us as we continue to create a successful, long term program that reinvigorates the Staghorn and other coral species around all of the Cayman Islands.  We can surely use your help.  This is working.

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