Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

Seeds for Snapper: Scaling up Seagrass Restoration Using Community Power (#48)

Rachel Austin 1 , Tania Douthwaite 2 , Steve Pursell 3 , Domenic Holland 3 , Marion L Cambridge 1 , Giulia Ferretto 1 , Gary A Kendrick 1
  1. University of Western Australia, Perth, WA , Australia
  2. Blueback Freediving and Yoga, Perth, WA, Australia
  3. Ozfish Unlimited, Ballina, NSW, Australia

Cockburn Sound near Perth, Western Australia, is a seagrass-dominated ecosystem where seagrass coverage has declined from 4200 ha to 900 ha between 1954 and 1978 due to poor water quality. Water quality has since improved but meadows have shown minimal recovery, thus it is imperative that seagrass restoration at ecologically relevant scales is conducted. The most cost-effective way to conduct large scale restoration is to use seeds that are naturally produced in large quantities. In the case of Posidonia australis, one of the dominant species in Cockburn Sound, millions of buoyant fruit are produced in Nov/Dec that release a single seed which sinks to the bottom after hours to days of surface dispersal. The ‘Seeds for Snapper’ program uses university and community volunteer divers to collect fruit in-situ prior to release, it is then stored in circulating tanks from which the seeds are collected then dispersed into restoration sites from boats. We have been able to increase seed restoration from ~180 000 to over 1.2 million seeds per season in the space of three years. This simple methodology results in seedling densities of up to 46 m-2, compared to 0-2 m-2 in naturally seeded areas after 3 months of establishment.