Corals

Mass Coral Spawning Expected at End of Month (March) on Australia's Reefs

One of the most spectacular natural events in Western Australia - the annual mass autumn spawning of corals - will occur off parts of the coast in the last week of March. Environment Minister David Templeman said more than 250 species of coral had been identified around areas such as the Dampier Archipelago, the Abrolhos lslands and in the Ningaloo Marine Park. The majority of these would synchronise their reproduction to spawn on a few nights of the year.

Ready to Release Releasing Eggs

Releasing Sperm

“In Western Australia (WA), this means corals will generally spawn seven to 10 days after the full moon in March-April, when the weather is typically hot and balmy.” Mr Templeman said. “The mass spawning is a mechanism to facilitate successful reproduction. By spawning at the same time and when the water movement is minimal, corals maximise the concentration of eggs and sperm thereby increasing the chances of fertilisation. The simultaneous spawning of many different species at night ensures enough coral larvae survive predators which will have an excess of food over a short period...”

Mr Templeman said if coral spawning occurred in extremely calm weather, the spawning could be so dense that it effectively ‘choked’ the surrounding waters leading to massive numbers of fish dying as a result of a lack of oxygen. The coral spawning also coincides with the arrival of the whale sharks that feed on microscopic organisms.

It's to scale, but that's about it

Growing Coral in Laboratory to Restore Damaged Reefs

Scientists at the National Coral Reef Institute are currently growing more than 400 corals from the larval stage as part of NOAA-funded research, and will transplant them to restore damaged coral reefs.

Producing juvenile corals from the larval stage for transplantation is better for the health and longevity of coral reefs because it produces new coral, rather than moving around already existing fragments collected in the field. NCRI is also evaluating this technique to raise and restore populations of staghorn coral, a species recently listed by NOAA as threatened under the Endangered Species Act.

Placing transplanted coral sections back in living reefs is a time-consuming process, with four divers each spending 70 minutes under water to attach 88 coral fragments. Each is numbered and will be monitored for growth.

NCRI has successfully raised more than 100 juvenile mustard hill corals and more than 300 great star corals, both essential species for the development and growth of coral reefs. The juvenile corals are being kept in indoor aquaria at the NCRI facility at the Nova Southeastern University Oceanographic Center near Ft. Lauderdale, Fla., and then are relocated to the outdoor coral husbandry system. If the corals successfully grow large enough in the outdoor system, they will be transplanted to damaged reefs...

Coral reefs, a critical part of the ocean ecosystem, teem with fish, lobsters, sponges, sea turtles, and thousands of other creatures that rely on them for their survival. Coral reefs also are important to the economy, providing millions of people around the globe with food, coastal storm protection, and jobs. Nearly a quarter of the world’s reefs are under imminent risk of collapse from human pressures, and a fifth have already effectively been destroyed and show no immediate prospects for recovery.NOAA is funding this research to develop tools to help environmental managers address these issues.

Nedimyer and other scientists are also taking note of the role spiny sea urchins may play in cleaning and protecting coral reef species.

The small, black sea creatures with long, sharp spines were very common in Florida Keys waters thirty years ago, but then virtually disappeared in the 1980's, because of a disease. Now they are starting to come back, and researchers have noticed they seem to promote the health and growth of corals by eating away algae and seaweed. As scientists contemplate coral planting programs, they are also considering the need to replant sea urchins with them.