Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

Determining the spatial distribution and temporal variability of fish and invertebrates in Cockburn Sound (#86)

Daniel E Yeoh 1 , Peter J Mitchell 1 , James R Tweedley 2 , Danielle J Johnston 1 , Gary Jackson 1
  1. Department of Primary Industries and Regional Development, Perth, WA, Australia
  2. Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Perth, WA, Australia

Cockburn Sound (CS) is a diverse and ecologically important marine embayment in the Perth metropolitan region, which is heavily utilised for a multitude of recreational, commercial and industrial activities. In 2021, the State Government announced plans to develop a new port for Perth within CS, and a project initiated to collect rigorous contemporary data to inform design and underpin necessary environmental impact assessment. To assess potential impacts on fisheries and aquatic resources several government agencies and universities are working on a collaborative research program to investigate species distributions, stock connectivity, trophic dynamics, invasive species, and effects of suspended solids and climate change on biota.

This presentation focuses on methods used to determine the distribution and abundance of the various life stages (larvae, juvenile and adult) of fish and invertebrates throughout CS during different times of year. These data will be used quantify relationships of communities and key species with various habitats and environmental variables, allowing the development of predictive distribution models and maps. In turn, outputs from this research will support mitigation advice to limit the effects of port construction on various species, and form a baseline for on-going monitoring of populations into the future. Building on several existing sampling regimes, a comprehensive two-year field program began in mid-2021, with monthly sampling occurring using a diverse range of methods (including trawls, seines, BRUVs, crab traps, bongo nets, squid jigging, light traps and hydro-acoustics). An overview of the first year’s sampling, highlighting innovative survey techniques, findings and spatio-temporal trends, and the successes and challenges encountered so far will be presented.