Deaf Threat to Tropical Fish

Posted by Douglas DuHamel Apr 29, 2008

If you or I went deaf, we would not blame it on global warming; however hotter seas can pose a problem for young coral fish.

These fish are more likely to get misshapen ear bones and are most apt to get lost and die. According to a study on fish around Lizard on the Great Barrier Reef in Australia, warmer waters just make the problem more intense.

After hatching in the open seas, most fish spend a few weeks out in the open waters of the seas to adjust all their senses. Then they go to the reefs to settle down. The key factor of them finding home is sound.

The fry have to seek out and listen to the high-frequency noises made by invertebrates like shrimp and sea urchins. In turn, they have to avoid the low frequency noises made by adult fish and crashing waves.

Monica Gagliano, at the Australian Institute of Marine research in Townsville Queensland, has discovered that at the time of hatching, just over 50% of all Ambon damsel fish have ear bones or asymmetrical otolith (which is a bad thing). A team of scientists suspect that it might be impossible for these fish to pinpoint the origin of a sound, which in turn, increases their chances of getting lost in a big ocean.

Gagliano says that an unpublished article shows that exposing adult reef fish to higher water temperatures and increasingly acid waters both of which are associated with global warming, increase the percentage of offspring born with asymmetrical otoliths