Using metabarcoding to identify threats to key trophic interactions supporting a commercial fishery in a climate change hotspot

Mr Owen Holland1, Dr Mary Young1, A/Prof Craig Sherman1, Dr Mun Hua Tan2, Dr Harry Gorfine2, Dr Ty Matthews1, Dr Adam Miller1

1Deakin University, Warrnambool, Australia, 2School of Biosciences, University of Melbourne, Melbourne, Australia

Abstract:

Worldwide, rising ocean temperatures are causing declines and range shifts in marine species. The direct effects of climate change on the biology of marine organisms are often well documented, yet knowledge on the indirect effects, particularly through trophic interactions, is largely lacking. Using DNA community metabarcoding, we interrogated abalone stomach content to identify the relative dietary composition of macroalgae in blacklip abalone (Haliotis rubra) across the Victorian coastline. Dietary assessments indicate primary dependency on a widespread macroalgal species (Phyllospora comosa) which we show to be in state of decline due to ocean warming, resulting in abalone biomass reductions. Niche models suggest further declines in P. comosa over the coming decades and ongoing risks to H. rubra. Thus, we provide evidence of ocean warming decoupling critical trophic interactions supporting a commercially important mollusc in a climate change hotspot. This study highlights the importance of studies from climate change hotspots and understanding the interplay between climate and trophic interactions when determining the likely response of marine species to environmental changes. Given the value of these outputs, further work implementing the same methodology with eDNA and other community DNA samples would help reveal similar trophodynamic vulnerabilities in other ecosystems, and should be considered to ensure the most comprehensive assessment of the community is achieved.


Biography:

Owen is a PhD candidate conducting genetic, physiological and ecological research on Australian blacklip abalone (Haliotis rubra) with a focus on the commercial fisheries and aquaculture sector. Owen is working closely with industry collaborators, with the end goal of improving the long term resilience, sustainability and biosecurity of the abalone industry in Australia. Specifically, Owen’s research is focused on a) characterising abalone dietary composition and identifying how climate change has impacted trophic interactions in abalone, b) attempting to identify potential historically selected AVG (abalone viral ganglioneuritis) resistant genotypes and c) determining the relative thermal tolerances of abalone stocks spanning major thermal habitat gradients. Additionally, Owen works alongside an extended group of collaborators applying his technical genetic skills to multiple fields within the ecological sciences, particularly in the eDNA space.

Date

Mar 21 - 23 2022
Expired!