copyright 1975 by Shohei Shirai
copyright 1975 by Shohei Shirai
A Population Explosion:
In the early 1960s, the Crown-of-Thorns Starfish went through a "population explosion". No one knows how the starfish increased so quickly. Some people think that they were cut in half and then it made two starfish. Because if you cut a starfish's leg off it will just grow back. So when you cut it in half, you have just created two starfish. Others think that the Giant Triton Shellfish (starfish's predator) were taken off the reef by shell collectors. 100,000 tritons were taken from the reef.
Starfish Armies:
Most starfish are nocturnal animals. It is very rare to see starfish awake in the day. But since there are so many starfish they are up night and day eating the coral. A starfish eats coral by turning its' stomach inside out and then sucks it in, only leaving coral skeletons. In only twelve hours a starfish could eat 40 to 50 years' worth of coral.
The hungry Crown-of-Thorns Starfish armies are sometimes 30 feet wide and 300 feet long. A hundred starfish may gather on a patch of coral the size of a small room. They fasten themselves to the coral branches and each other until they look like a giant cactus.
Today the starfish population explosion continues. During one month each year, each female Crown-of-Thorns Starfish releases millions of eggs into the water.
Starfish Predators:
Normally, coral polyps eat millions of starfish larvae. Now, because so many polyps have been killed, more starfish larvae survive to become adults. All the dead coral provide more cracks and crevices for larvae and eggs of the Crown-of-Thorns Starfish.
Repairing the Damage:
The Crown-of-Thorns Starfish has invaded several parts of the Great Barrier Reef. In some places, armies of starfish have killed most corals on an entire part of the reef.
The starfish problem is truly enormous. The world's largest oil spill could not have damaged the Great Barrier Reef as much as the Crown-of-Thorns Starfish has damaged it. Millions of coral colonies have been killed, and more are being destroyed.
Problems with People:
Just as in other parts of the world, the ocean life of the Great Barrier Reef is being threatened in many ways. Sewage is being pumped into the ocean. Some people dig up the bottom of the harbor to make it deeper. Pesticides sprayed on farm crops flow into the streams and out into the ocean.
As more and more tourists come to explore the reefs, new buildings and more food are needed. Visitors are collecting more shells and doing more deep-sea fishing, spear fishing and boating than ever before.
People can (and do) change this most beautiful natural wonder of the world. A lot of these changes are coming to the Great Barrier Reef.
