Dive-Hive.com: aquatic life

Invisible fish warn the reef is at risk

Ichthyologist wonders where the gobies are at the Great Barrier Reef?

The smallest fishes on Australia's Great Barrier Reef are sending out a warning that profound change is taking place in the Reef's natural systems, probably as a result of human activity.

At 25-45mm in length, the gobies are so small and cryptic they are often invisible to the casual visitor – but they make up almost half of all the fish life on the reef, says ichthyologist Professor David Bellwood of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

"These fish may be tiny, but they are very important.  They are telling us that the world has changed, and in ways we do not understand.  That we may not be able to manage things as well as we hoped," he says

"In 1998 there was a major coral bleaching event that affected corals across a huge area of the reef. After some years, quite a lot of the coral has recovered – and looks more or less as it once did."

"But the gobies have not come back. Something is not right if the fastest breeders of the reef are still missing.  Overall, the coral fish fauna are still in a degraded state – after 30 generations."

The full report can be found at coralcoe.org.au.