When ocean temperatures soared off the coast of Mauritius—an island nation east of Madagascar in the Indian Ocean—last summer, most coral reefs bleached and died. But one group of corals remained vibrant and healthy—achieving a 98% survival rate while neighboring wild reefs suffered 80% bleaching.
The secret? These corals were bred specifically for heat resistance.
Dr. Nadeem Nazurally and his team have pioneered a selective breeding program that's giving coral reefs a fighting chance against warming oceans. By collecting eggs and sperm during coral spawning events, they breed generations of corals in protected nurseries, selecting only those that thrive in warmer water.
This breakthrough in Mauritius is part of a global movement toward "assisted evolution" for corals. Scientists worldwide are developing multiple approaches: cross-breeding heat-tolerant species, conditioning corals through gradual temperature increases, engineering tougher symbiotic algae, and even using probiotics to boost coral health.
UK researchers recently demonstrated that corals can adapt to heat stress within just a single generation through selective breeding. Even better news: studies show no trade-offs between heat tolerance and growth or fertility, meaning these tougher corals won't sacrifice their reproductive success.
Protecting coral reefs is important because they support 25% of all marine species despite covering less than 1% of the ocean floor. They protect coastlines from storms and erosion and provide livelihoods for through tourism and fisheries.
While coral restoration can't replace climate action, it buys precious time for these critical ecosystems.