Colonisation trajectories of fish fauna on Turner Artificial Reef, Scarborough

Abstract

Artificial reefs are a well-recognised technique for enhancing local fisher resources, and providing recreational fishing and diving opportunities (Fowler and Booth 2012). In several instances, they have been used in management contexts (Feary et al. 2011), for example as a trade-off for closure of sensitive or impacted habitats. In other situations, they appear “accidentally”, as a consequence of hard substrate installed to support infrastructure such as wind farms (Reubens et al. 2013). Several artificial reefs exist in Moreton Bay and Hervey Bay, established by government agencies, user groups or private citizens, and in place for varying lengths of time. There is very strong anecdotal evidence for their efficacy in providing habitat for benthic colonisers, and thereby for fish and invertebrates, enhancing biodiversity at the local scale. In MPA contexts, they can be installed as ‘compensation’ habitat, providing additional opportunities for recreational fishers when natural reef areas have been closed to fishing. They also provide popular destinations for recreational divers; in both cases they may make significant contributions to local economies (Sutton and Bushnell 2007; Whitmarsh et al. 2008). However, there is uncertainty about the colonisation trajectory of new artificial reefs in estuarine settings, and ongoing debate about whether they enhance marine productivity at the larger scale, or act primarily as aggregating devices (Brickhill et al. 2005). This is of crucial interest to managers. In 2015, three small artificial reef structures were installed in Moreton Bay and Hervey Bay, representing an opportunity to study the colonisation trajectory for fish associated with these structures, in the context of adjacent soft sediment and natural reef structures. This document reports on investigations into the colonisation trajectory of fish species of Turner Artificial Reef, located off Scarborough, Queensland, with the particular aims to: • Compare the artificial reef fish fauna to that of adjacent soft bottom and natural reef areas, to determine if there is an identifiable artificial reef effect, and • To examine changes in the fish fauna at artificial reefs, soft bottom and natural reef sites over time, to determine the trajectory of any effect.