A beautiful black, white and yellow butterflyfish, much admired by eco-tourists, divers and aquarium keepers alike, may be at risk of extinction, scientists have warned.
The case of the Chevroned Butterflyfish is a stark example of how human pressure on the worlds coral reefs is confronting certain species with blind alleys from which they may be unable to escape, says Dr Morgan Pratchett of the ARC Centre of Excellence for Coral Reef Studies Media Release and James Cook University.
In a study published in the journal Behavioural Ecology and Sociobiology Dr Pratchett and Dr Michael Berumen of Woods Hole Oceanographic Institution (USA) warn that the highly specialized nature of the feeding habits of this particular butterflyfish the distinctively patterned Chaetodon trifascialis - make it an extinction risk as the worlds coral reefs continue to degrade due to human over-exploitation, pollution and climate change.
The irony is that these butterflyfish are widespread around the world, and youd have thought their chances of survival were pretty good, Dr Pratchett said today.
But they only eat one sort of coral Acropora hyacinthus and when that runs out, the fish just disappear from the reef.
The team found it hard to believe a fish would starve rather than eat a mixed diet, so they tested C. trifascialis in tank trials on a range of different corals. The fish grew well when its favourite coral was available but when this was removed and other sorts of corals offered, it grew thin, failed to thrive and some died.
We call these kinds of fish obligate specialists. It means they have a very strong dietary preference for one sort of food, and when that is no longer available, they go into decline. We still dont have a satisfactory scientific explanation for this, as it seems like rather a risky tactic in evolutionary terms but it must confer some advantage provided enough of its preferred food is available, Dr
|Contact: Dr. Morgan Pratchett|
ARC Centre of Excellence in Coral Reef Studies