Poster Presentation Australian Marine Sciences Association 2025 Conference

Bioaccumulation of metals in the critically endangered Maugean skate, Macquarie Harbour, Tasmania. (#138)

Zoe Robertson 1 , Patricia Corbett 1 , Justin Bell 2 , Damien Callahan 3 , Julie Mondon 1
  1. Deakin University, Warrnambool, VIC, Australia
  2. University of Tasmania, Hobart
  3. Deakin University, Burwood, VIC, Australia

The critically endangered Maugean skate displays a high site fidelity and foraging preference in shallow, soft-sediment benthic habitats within a limited 70 km2 range (1). Historical copper and gold mining has contributed significantly to legacy sediment contamination of Macquarie Harbour from wastewater and acid drainage via the Gordon-Franklin and King rivers catchments (2). Mean Hg (3.38 +/- 0.25 mg/kg) and As (29.27 +/- 3.48 mg/kg) concentrations in muscle were respectively 4 - 5 times higher than in liver, whilst Cu (26.34+-14.76 mg/kg) was eighteen times higher in liver compared to muscle. Cd (0.99 +/- 0.12) and Pb (0.42 +/- 0.05) in liver also indicates a broader suite of bioavailable non-essential metals present in Macquarie Harbour. No significant correlation was evident between total metals in muscle and skate length, nor between sexes and length. Mean Hg bioaccumulation in Maugean skate was twice that recorded in White spotted skate from the legacy metals-contaminated Derwent River (3), however no ecotoxicological impact from elevated metals bioaccumulation in Maugean skate has been investigated. This evidence of non-essential metals bioaccumulation is critical to understanding the environmental metals legacy of Macquarie Harbour and bioavailability to the skate and provides essential baseline bioaccumulation concentrations for future comparison (4).

  1. (1) Bell, J.D., Lyle, J.M., Semmens, J.M., Awruch, C., Moreno, D., Currie, S., Morash, A., Ross, J., and Barrett. (2016) Movement, habitat utilisation and population status of the endangered Maugean skate and implications for fishing and aquaculture operations in Macquarie Harbour. Fisheries Research and Development Corporation Project No. 2013/008. Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, January. CC BY 3.0
  2. (2) Stauber, J.L., Benning, R.J., Hales, L.T., Eriksen, R., Nowak, B. (2000) Copper bioavailability and amelioration of toxicity in Macquarie Harbour, Tasmania, Australia. Marine and Freshwater Research 51, 1 - 10
  3. (3) Thomson, J.D. (1985) Mercury concentrations of the axial muscle tissues of some marine fishes of the Continental shelf adjacent to Tasmania. Australian Journal of Marine and Freshwater Research 36, 509 - 17
  4. (4) Robertson, Z. (2021) Bioaccumulation and maternal transfer of metals in elasmobranchs. Doctoral Thesis. Deakin University.