Batfish Sneak Up On Scientists

I've been studying a lot about herbivorous reef fishes lately because, as it turns out, they have some similarities with turtles in the role they play in maintaining reef systems, ie, they make sure that the garden doesn't become overgrown by grazing on all the growth. Along the way I came across a fascinating paper (Bellwood et al, 2006) which appealed to both my interest in reef systems and to my delight in watching the environment turn scientists on their head. Before I explain the story, bear in mind this is drawn from an extensive scientific paper which discusses many other ideas and concepts and I have simply drawn this thread from the bigger picture to illustrate a point, okay? Okay, here we go.

So… these marine scientists were looking at what might happen to coral reefs after they die, which they've all come to accept is inevitably going to happen. They expect that once the coral is dead, the algae will have a better chance for space and the herbivorous fishes will have a field day. They call this a 'phase shift' from coral reef to algal reef. To test their theory, they take a closer look at a coral reef, identify about 43 species of herbivorous fishes they expect might take part in the process given that they are already doing the onsite herbivory job and they experimentally induce a large scale phase shift to the area.

But something happens that they didn't expect. The 43 herbivorous fishes weren't the ones most responsible for eating all the extra algae. The fish that did was not even on the list. To their surprise, most of the phase shift reversal work was outsourced to a single batfish species (Platax pinnatus) which was previously thought to feed at “No Spines”, the local invertebrate eatery.

The results show that the environment is an amazing and complex system which can and will recover from disturbance in ways you had never considered were possible. Human induced disturbances to wild fauna populations such as over-harvesting, even at a local scale (I’m looking at you Margiris/Abel Tasman) will also have effects the world’s leading scientists cannot predict now, or in the future.

Tread lightly.


Reference:
David R. Bellwood, Terry P. Hughes, Andrew S. Hoey. 2006. Sleeping Functional Group Drives Coral-Reef Recovery Current Biology, Volume 16, Issue 24, 19 December 2006, Pages 2434–2439
http://dx.doi.org/10.1016/j.cub.2006.10.030