Oral Presentation Australian Society of Fish Biology and Oceania Chondrichthyan Society Conference 2016

Efficiency and versatility underpin the global ecological success of a single fish genus in extreme coral reef habitats (#94)

Christopher Fulton 1 , Peter Wainwright 2 , Andrew Hoey 3 , David Bellwood 3
  1. Research School of Biology, The Australian National University, Canberra, ACT, Australia
  2. Evolution & Ecology, University of California, Davis, CA, USA
  3. ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, Australia

Phenotypic innovations can allow organisms to relax abiotic selection and facilitate their ecological success in challenging habitats, yet we have relatively little evidence for this phenomenon at macroecological scales. We examined the relative abundance of coral reef wrasses and parrotfishes (f. Labridae) across three ocean basins and the Red Sea to reveal the consistent global dominance of extreme wave-swept habitats by a single fish genus - Thalassoma - which had abundances up to 15 times higher than any other sympatric labrid. Winged pectoral fins were a key part of this global success, since numerical dominance by Thalassoma was contingent upon the presence of high intensity wave energy where winged fins allow for efficient locomotion. Notably, the extent of ecological success varied with species richness and the presence of congeneric competitors. While many fish taxa have evolved winged pectoral fins, Thalassoma appears to have combined efficient high-speed swimming (to relax abiotic selection) with trophic versatility (to maximise exploitation of rich resources) to exploit and dominate extreme coral reef habitats around the world.