Artificial structures such as sunken ships and habitat enhancement structures have been deployed around the world with many shown to benefit local fish populations and hence fisheries. A number of different artificial structures are already deployed in southwest WA for a wide range of purposes, including; creating recreational fishing and tourism opportunities, aquaculture developments, shipwrecks, as infrastructure (e.g. breakwaters and jetties) and, in the past, for disposal of obsolete equipment and vessels.
One of the key questions for any artificial structure is how the various local fish species utilise or associate with the differing structures resulting in–concentration/redistribution of existing organisms and biomass, and/or changes in local productivity and biomass. After more than 10 years involvement in a range of projects surveying different artificial structures in southwest WA, a number of insights have been gained into addressing some of these key questions for particular WA species using underwater video techniques.
The talk will cover the various artificial structures surveyed in southwest WA, including the Southwest artificial reef trial, Augusta abalone mariculture lease site and various dive sites (e,.g Busselton jetty, HMAS Swan & MV Lena). Details of methods used and their value for assessing fish associations with underwater structures along with insights gained on how various WA fish species, such as WA Dhufish (Glaucosoma hebraicum) and Samsonfish (Seriola hippos), utilise these different structures at different life history stages will be discussed along with the potential benefits these structures, possible effects on the wider ecosystem and comparison with natural sites.