Oral Presentation Australian Society for Fish Biology Conference 2024

The ecological succession of fish and benthic communities on offshore artificial reefs (111287)

Stephanie H Woolley 1 , Iain Suthers 1 , Hayden Schilling 2 , Alistair Becker 2 , Johan Betrom 3
  1. UNSW, Sydney, NSW, Australia
  2. Department of Primary Industries, Fisheries, Port Stephens, NSW, Australia
  3. SeaO2, Sydney

The succession of fish communities on offshore artificial reefs (OARs) is crucial for enhancing effective fisheries management on increasingly urbanised coasts. Community establishment depends on the species’ behaviour and also reef design/structure. The fish and biofouling communities on two Batemans Bay OARs were monitored by Remotely Operated Vehicle (ROV) on 40 occasions over 2 years post-deployment in December 2022. Fish communities stabilised 18 months post-deployment with 36 species, although accumulation rates differed among three depth zones above the sand. Biofouling accumulated rapidly post-deployment but took longer to diversify than fish, with 5 broad groups at 24 months post-deployment (macroalgae, sponges, epilithic algae matrix, barnacles, cnidarians and ascidians). The succession pattern was further compared at 5 different OARs, 2 concrete (Port Macquarie and South Sydney) and 3 steel (Newcastle, Sydney and Wollongong). These OARs were surveyed using Baited Remote Underwater Video (BRUVs) which prevented direct comparison with ROV survey. The 5 reefs had similar rates of initial colonisation yet by 22 months post-deployment two reefs (port Macquarie and Sydney) had higher cumulative richness (>25 species) than the others. The fish community therefore is a combination of production and attraction of fish, and of season, reef age and distance to natural reefs.