Oral Presentation Australian Society for Fish Biology Conference 2017

Freshwater mussels as ecological engineers in permanent water refuges in southwestern Australia (#101)

Justin A Benson 1 , Paul Close 1 , Barbara A Cook 1 , Alan Lymbery 2
  1. Centre of Excellence in Natural Resource Management, University of Western Australia, Albany, WA, Australia
  2. Freshwater Fish Group & Fish Health Unit, Centre for Fish & Fisheries Research, Murdoch University, Murdoch, Western Australia, Australia

More than half of the global river network is intermittent, shrinking to a series of isolated pools during periods of no-flow. More frequent or prolonged drying events associated with climate change will reduce the quantity and quality of these pools and impact their ability to support aquatic organisms during periods of no-flow. As filter-feeders, freshwater mussels clear the water column of suspended material, including nutrients, algae and sediment, and deposit them on the benthos, altering the distribution and abundance of essential resources for primary and higher order consumers including fish. They may maintain clear water conditions in enclosed systems by removing the accumulated wastes of organisms, suppressing toxic cyanobacteria and preventing algal blooms, so may be important in preserving the integrity of river-pool refuges. Many rivers have multi-species mussel assemblages, however, southwestern Australia has only one species, Westralunio carteri, which is likely to be particularly important to rivers in the region. The recent range decline of W. carteri may impair refuge-pool function and threaten the persistence of the unique aquatic fauna including fish. This presentation will highlight the potential role freshwater mussels play as ecosystem engineers by drawing on evidence from mussels in other regions around the world and preliminary quantitative evidence of filtration rates of W. Carteri in southwestern Australia.