Oral Presentation Australian Society for Fish Biology Conference 2017

Geographic distributions and assemblages of labrids along the south west coast of Western Australian over the past decade   (#63)

Jack Parker 1 , Euan Harvey 1 , Benjamin Saunders 1 , Scott Bennett 1
  1. Department of Environment and Agriculture, Curtin University, Bentley, WA, Australia

This research sought to evaluate and compare the Labridae assemblages in the temperate and subtropical marine community’s along the southwest of Western Australia, comprising seven regions along Western Australian Coastline from Geraldton to Esperance.  Survey data was collected in 2006 and again in 2015 using diver operated stereo-video (DOV) transects focusing on the Labridae family which includes Scarine Labrids and Wrasse. Through a comparison of the Labridae assemblage from the two data collections it was determined that at every one of the 7 regions the Labridae assemblage had changed significantly. While the change in the Labridae assemblage was larger in the northern most marine environments, there were still significant changes in the temperate assemblages. Other notable trends along the coast were the increase in warmer temperate labrids and the appearance of labrids in locations 2015 that were not seen in 2006. While most labrids have increased in numbers, three temperate species that have instead declined. These changes in the assemblage could be attributed to several environmental changes. Since the 2006 data survey there was a large marine heat wave in 2011 and the canopy forming alga in the northern coastal areas have also been reduced. Sea surface temperatures have also increased at each region. This increase 4 years after, a lack of recovery along the western coast and significant changes in Labridae assemblages over the entire survey area indicate a permanent change to Labridae communities. There has been reported changes to the cooler temperate waters of Albany, Bremer Bay and Esperance, however our results gathered in 2015, continued ocean warming and the predicted increase in frequency of large marine disturbance events, suggest that changes may be occurring on the south coast and may follow the environmental trends of the warmer sub-tropical waters of Western Australia.