When the moon is full and everything is just so right!

Last week, with the full moon at the end of October, the coral reefs, in the Grand Port of Mahebourg and Pointe d’Esny, Mauritius, had their annual mass spawning! Everything must have been perfect for them to feel romantic! The light, water temperature and calmness and probably some more mysterious factors all had to be in sync for this magical moment. The usually pristine blue lagoon turned pink with the eggs and sperm of these special animals, trying to reproduce so that they can thrive.

I use the word thrive for several reasons. Sexual reproduction by mass coral spawning has a greater genetic diversity than asexual division or splitting. This genetic diversity contributes to the chances of the species survival. The mass spawning gives the individual eggs and sperms a greater chance of survival and fertilisation. It also increases the reach of the geographic range where fertilised eggs will drift and the developing larvae will swim until it settles to develop further.

We are all clear on the fact that these animals are the builders of the biggest naturally created mega structures in the world. The Great Barrier Reef is visible from space and just recently two new pristine deep-sea coral reefs were discovered in the Galápagos Marine Reserve. The larger of the two is 300m beneath the ocean and over 800m long! These stony coral species have thrived there for thousands of years. We learn from this that our understanding of reef ecosystems will still improve as we discover more of these unexplored coral reefs.

It is exciting to think that we still have the opportunity to discover more large pristine coral reefs and that these corals in Pointe d’Esny are healthy enough to reproduce sexually. Just more than 3 years and 3 months ago, on 25 July 2020, the MV Wakashio oil spill occurred on this reef. All who witnessed the devastation and those involved in the clean-up as well as the families who suffered great losses as a result of this tragedy refer to it as one of the darkest periods in Mauritian history. It was a dark day indeed!

Oil spills are only one of the pollutants that threaten corals.  There is also urban, agricultural, industrial and pharmaceutical pollution. Sewage, fertilizers, pesticides and increased acidity due to excess carbon dioxide also challenge the health of the corals. Then there is the threat of rising water temperatures due to Global Warming, leading to coral bleaching. There are also areas where Bottom Trawling and fishing with dynamite still destroy complete reefs. Sadly the industries depending on coral ecosystems for their survival, like the boats used in the Tourism and Fishing industries, destroy corals with negligent navigation and the use of anchors. These are only the threats caused by human activity. There are even more!

There are many role players addressing these threats and challenges and I am personally so grateful for every individual who contributes to Coral Conservation and Restoration. It is my dream to someday help to clean a healthy coral nursery or transplant corals to a safe area where I can check in on their growth from time to time.  

I pointed out some of the challenges faced by Corals to highlight the extent of the enormity of this full moon occasion that was witnessed last week. Corals making babies, against all odds!

By Lynette Gerber-Lochenkov