Baby Coral, Juvenile Fish can Smell Difference between Good and Bad Reefs: Study

Banning fishing in areas where coral reefs have decayed and seaweed has taken over is not enough. Active steps need to be taken, say researchers of a new study.

They have conducted an experiment in which baby corals and very young fish were able to differentiate between good and bad reefs. It is the first study, which has shown that coral can react to smells in water.

Researchers also noticed an important thing that seaweed needs to be controlled to get back the healthy habitats. "If you're setting up a marine protected area to seed recruitment into a degraded habitat, that recruitment may not happen if young fish and coral are not recognizing the degraded area as habitat", said study's lead author, Dr. Danielle Dixson from the Georgia Institute of Technology.

The research team found a nice experiment setting. They chose three marine protected areas off the coast of Fiji. These marine areas host very healthy coral reefs and were apt for the experiment as they were adjacent to heavily fished areas full of seaweed.

Study's senior author Prof. Hay said they took water from both the places to the lab. An experiment was carried out on fish and corals. Firstly, fish were placed in a special chamber and were offered a choice between the two.

All the species, even every young fish, chose the water from healthy coral reefs. In fact, they spent most of their time in the chamber having water from healthy coral reefs. Next turn was of the corals. Researchers were not expecting much from them, but they were completely surprised when corals also showed same behaviour and swam into the water from healthy coral reefs.

Study researchers came to know about main factor, which is smell of specific seaweeds that keeps fish away from the water. Fish also avoid going into the water having decayed reefs. If bad smells by the seaweed can be removed and the abandoned areas are seeded with pleasant perfumed coral, then these insights can make things better.