CORAL REEFS: Spawnin’ Time

Every year, when the cycle of the moon and temperature of the ocean is just right, the coral in coral reefs begin to spawn. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Corals are jellyfish-like animals which secrete a hard skeleton as they grow. Coral reefs are collections of many different species of corals. Now, at this time of year, we’re likely to see all of those species spawning at once.

“And the reason they do this is that if there’s a whole lot of eggs and sperm in the water at once, the fishes and the other predators do not have a chance to eat them all. They get full, in other words, so many of these larvae and eggs have a chance to make it and grow up to form new colonies.”

Dr. Dennis Thoney is the General Curator of New York’s Aquarium for Wildlife Conservation. He tells us how it is that these different species come to spawn at the same time.

“What we find is that corals on reefs respond to the moon and other cycles — temperature and other things on the reef. It’s not only induced by external cycles that are going on, but also the chemical stimuli that are actually in the water as one or two of these colonies start to spawn. And so when one goes and starts spawning, many of the other ones will start spawning also.”

According to Dr. Thoney, the timing of the spawning is so precise that with just a bit of information about the moon and water temperature, you can predict, to the day, when the coral will spawn.

Pulse of the Planet is presented by the American Museum of Natural History. I’m Jim Metzner.

CORAL REEFS: Spawnin’ Time

The temperature of the ocean and the phase of the moon are just two factors that determine when coral will spawn.
Air Date:12/23/1997
Scientist:
Transcript:

Every year, when the cycle of the moon and temperature of the ocean is just right, the coral in coral reefs begin to spawn. I'm Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Corals are jellyfish-like animals which secrete a hard skeleton as they grow. Coral reefs are collections of many different species of corals. Now, at this time of year, we're likely to see all of those species spawning at once.

"And the reason they do this is that if there's a whole lot of eggs and sperm in the water at once, the fishes and the other predators do not have a chance to eat them all. They get full, in other words, so many of these larvae and eggs have a chance to make it and grow up to form new colonies."

Dr. Dennis Thoney is the General Curator of New York's Aquarium for Wildlife Conservation. He tells us how it is that these different species come to spawn at the same time.

"What we find is that corals on reefs respond to the moon and other cycles -- temperature and other things on the reef. It's not only induced by external cycles that are going on, but also the chemical stimuli that are actually in the water as one or two of these colonies start to spawn. And so when one goes and starts spawning, many of the other ones will start spawning also."

According to Dr. Thoney, the timing of the spawning is so precise that with just a bit of information about the moon and water temperature, you can predict, to the day, when the coral will spawn.

Pulse of the Planet is presented by the American Museum of Natural History. I'm Jim Metzner.