Seeding enhanced corals from existing stock by assisted larval transfer

There is significant genetic diversity within and among populations of many coral species on the Great Barrier Reef.

Enhanced coral performance interventions are also known as ‘assisted evolution’ as they aim to facilitate the sharing of this genetic diversity; to transfer desirable traits – such as heat tolerance, growth and fecundity – between coral species and populations.

Corals that survive mass-bleaching events, or those that thrive on naturally-warm reefs, are likely to possess heat-resistant genes.

This potential intervention aims to enhance the adaptation of local populations to expected future conditions by moving naturally warm-adapted corals (adults, fragments, spawn, larvae or juveniles) to reefs with less heat-resistant individuals.

High priority reefs would be seeded with natural coral stock captured into tanks during coral spawning and transported via large vessels. This aims to increase the number of corals from the spawning slick that ultimately recruit into reef populations.

This captured coral stock may receive additional treatments such as:

• microbial treatments, such as probiotics and manipulating the symbiotic organisms such as microalgae to enhance the performance for future conditions
• hardening (exposure to stressful environmental conditions to induce physiological responses that toughen corals).