Coral Mass Spawning Correlates To Temperature Rise

Acropora assemblage from Okinawa, Japan. (Credit: Andrew Baird)

While coral mass spawning is a well known phenomenon, the reason behind the huge spawning events was not clear until recently.

Researchers at the University of Copenhagen discovered that the trigger of the dramatic events is an upward flux of temperature, rather than a specific one. The timing of mass coral spawning is important, as the odds that coral sperm and eggs will meet and produce coral larvae are much higher with very large numbers of coral gametes interacting.

Research was conducted over a 16-year period in 34 eco-regions in the Indo-Pacific, including Kenya, French Polynesia and the Persian Gulf. The study involved over 80,000 colonies of coral.

Although there was some correlation with wind speed, scientists found it was not as strong as the relationship with temperature flux and there didn’t seem to be a strong relationship with any other marine parameters.

The new findings are expected to be a boon to reef tourism, as it’s now possible to predict when the best time will be for viewing unforgettable coral spawning events. In addition, practices that hurt early-stage coral, such as dredging, can be avoided until coral are less vulnerable.

Top image: Acropora assemblage from Okinawa, Japan. (Credit: Andrew Baird)