Artificial Reefs: Types, applications, trends in deployment and the development of a cost-effective method for monitoring their fish faunas

The focus of this thesis is on the design and use of artificial reefs and the development of a cost-effective method for monitoring their fish faunas. A review of habitat enhancement structures around the world, focusing primarily on artificial reefs, found that these structures have been used for a wide range of purposes such as sediment stabilization, mitigation of illegal trawling, enhancing recreational fisheries and the provision of additional habitat and nurseries for threatened fish stocks. Over time, there has been a growing trend in the use of purpose built reef modules as opposed to the use of materials of opportunity. Within Australia this has been most evident in the shift away from the use of tyres and steel vessels, to the use of specially designed concrete reef modules. As these structures can require financial investments within the millions, it is important to evaluate their effectiveness through post deployment monitoring. A central part of the citizen science monitoring project being developed by Recfishwest in Western Australia is the use of university students to extract information from the Baited Remote Underwater Video (BRUV) footage collected by recreational fishers. This study found that whilst observers recorded similar numbers of species and abundance (total MaxN), significant differences were present between observers in terms of their faunal compositions. This indicates that if inexperienced observers are used in the future as part of a cost-effective monitoring project, observer bias may be a potential source of error in the data and should be mitigated through observer training. Statistical analysis of footage collected from the Bunbury and Dunsborough artificial reefs using BRUVs found a significant difference in species composition between the footage from the two reefs but not between camera positions. However, increased camera soak time and footage collection over a greater temporal scale are needed to increase the reliability of the data. Whilst improvements to the sampling regime are recommended, the use of cost-effective BRUVs shows potential as an effective method for monitoring the fish fauna of artificial reefs using citizen science