Oral Presentation Australian Society for Fish Biology Conference 2017

The great escape: are marine blennies using land to avoid predation? (#113)

Chris Fulton 1 , Mae M Noble 2 , Thomas C Summers 3 , Terry J Ord 3
  1. Research School of Biology, The Australian National University, Canberra, ACT, Australia
  2. Fenner School of Environment & Society, Australian National University, Canberra, ACT 2601
  3. Evolution & Ecology Research Centre, and the School of Biological, Earth & Environmental Sciences, The University of New South Wales, Kensington , NSW , 2052

Ecological release from competition or predation is a common reason put forward to explain why animals make transitions into new environments. Supporting data for this phenomenon, however, is limited. Using a group of blennies who appear to be in the process of colonising land, we explored whether differences in aquatic versus terrestrial predation pressure may help explain the amphibious behaviour of these otherwise marine fishes. We found that amphibious blennies display a dynamic distribution within the intertidal zone, where they shift their peak abundance up and down the shoreline to remain above aquatic predatory fishes that periodically move into the intertidal on high tides. Deployment of blenny mimics confirmed a high risk of aquatic predation for blennies; significantly higher than levels of predation experienced by blennies above the waterline. Collectively, our evidence suggests that a differential in predation pressure may have played a key role in one of the most profound habitat shifts in the history of vertebrate biodiversity: the occupation of land by marine fish.