Coral reefs which have been destroyed by human activity often emit chemical cues which can upset fish and also corral larvae driving them away. Both fishes and Coral Larvae can smell coral reefs which have been damaged by human activity and avoid making their homes there.
A study carried out by the Georgia Institute of Technology has revealed that coral larvae are able to discern between damaged coral reef and healthy reefs.
Damaged coral reefs emit chemical cues that offend fish and corals, driving them away, reported. The study shows for the first time that coral larva can detect the difference between damaged and healthy reefs.
Coral reefs are exploited around the world and over fishing has depleted the number of herbivorous fishes which eat damaging sea weed off reefs. The study investigated how chemical signals which are sent by sea weeds offend young corals from settling in the area and so also the stink of water around the damaged reefs also puts off fishes. The study suggests that just designating the over fished coral reefs as protected may not work and fishes may still be driven away.
Danielle Dixson, an assistant professor in the School of Biology at the Georgia Institute of Technology in Atlanta, and the study’s first author, said “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,”
The researchers choose Fiji as their location for carrying out the study because Fiji has a number of marine protected areas. The research team put water from healthy and unhealthy habitats into a waterfall which permitted fishes to swim towards them. The fishes showed eight times more preference for healthy water while the Coral larvae preferred five times preference to healthy water. The team also found that seaweed-soaked water reduced the preference of the water by 86 percent for fish and 81 percent for coral larvae.
Mark Hay, a professor in the School of Biology at Georgia Tech and the study’s senior author said, “What this means is we probably need to manage these reefs in ways that help remove the most negative seaweeds and then help promote the most positive corals.”