James Tweedley

The global increase in population and the corresponding demand for sustainable fisheries has intensified the need for innovative fisheries enhancement and protection measures. One measure to be used in this pursuit is the deployment of artificial reefs (ARs). ARs have many definitions and purposes, but can be broadly defined as any man-made structure deployed in an aquatic environment to provide substrate or shelter for biota, particularly fish (Lima et al., 2019). In addition to offering physical shelter, ARs enhance ecological functions by increasing primary production and food availability. Mechanisms include (i) the provision of hard substrate for algal settlement (Choi et al., 2019), which in turn are fed on by invertebrate consumers, and (ii) increased upwelling caused by interactions between local hydrological forces and the physical presence of an AR, making nutrients more available, stimulating phytoplankton growth and increasing nutrient cycling in the immediate and surrounding AR area (Layman & Allgeier, 2020). These processes foster biodiverse and resilient aquatic ecosystems...

Artificial reefs are human-made or altered structures placed in an aquatic environment to mimic certain characteristics of a natural reef. Indigenous cultures have used artificial reefs to harvest aquatic food supplies for thousands of years, including indigenous Australians using artificial reefs as far back as 2,000 BC (Carstairs, 1988; Kerr, 1992). These early reefs were mainly constructed using materials of opportunity such as woody debris including bamboo, rocks and rubble and sunken vessels (such as ancient fishing boats). In more recent history, artificial reefs have advanced significantly, with innovations in design, materials, and purpose (such as coastal protection, tourism and fisheries enhancement). As of 2015, at least 120 artificial reefs had been deployed in Australian waters, with 11 noted in Western Australia (Bateman et al, 2015); however, the number is likely above 7,000 when considering there are more than 1,600 shipwrecks along the coast, jetties, ports and coastal infrastructure, subsea petroleum assets and other artificial reefs...

The WAMSI Westport Marine Science Program (WWMSP) is a $13.5 million body of marine research funded by the WA Government. The aims of the WWMSP are to increase knowledge of Cockburn Sound in areas that will inform the environmental impact assessment of the proposed Westport development and help to manage this important and heavily used marine area into the future. Westport is the State Government’s program to move container trade from Fremantle to Kwinana, and includes a new container port and associated freight, road and rail, and logistics. The WWMSP comprises more than 30 research projects in the biological, physical and social sciences that are focused on the Cockburn Sound area. They are being delivered by more than 100 scientists from the WAMSI partnership and other organisations.

This report, commissioned by the Department of Biodiversity, Conservation and Attractions (DBCA), describes the monitoring and evaluation of fish communities in Derbal Yirragan Djarlgarro (Swan Canning Estuary) during 2024 and applies the Fish Community Index (FCI) that was developed as a measure of the ecological condition of the estuary. This index, separate versions of which were developed for both the shallow (< 1.5 m), nearshore waters of the estuary and also for its deeper (> 1.5 m), offshore waters, integrates information on various biological variables (metrics). Each of these metrics quantifies an aspect of the structure and/or function of the fish community, and together they respond to a range of stressors affecting the ecosystem.

Fish communities were sampled using different types of net at six nearshore and six offshore sites in each of four management zones of the estuary (LSCE, Lower Swan Canning Estuary; CE, Canning Estuary; MSE, Middle Swan Estuary; USE, Upper Swan Estuary) during summer and autumn of 2024. As many fish as possible were returned to the water alive after they had been identified and counted. The resulting data on the abundances of each fish species from each sample were used to calculate a Fish Community Index score (0–100). These index scores were then compared to established scoring thresholds to determine ecological condition grades (A–E) for each zone individually and for the estuary as a whole, based on the composition of the fish community.

This report describes the monitoring and evaluation of fish communities in the Bindjareb Djilba (Peel-Harvey Estuary), Waangaamaap Bilya (Serpentine River) and Bilya Maadjit (Murray River) during the summer and autumn of 2023 using the Fish Community Index (FCI), which was developed as a measure of the ecological condition. This index, which was specially designed to work in south-western Australian estuaries, has versions developed for both the shallow, nearshore waters of the estuary (≤ 1 m deep) and also for its deeper, offshore waters (> 1 m deep) using an extensive fish data set from the 1970s to 2018. The index integrates information on various biological variables (metrics). Each of these metrics quantifies an aspect of the structure and/or function of estuarine fish communities, and together, they respond to a range of stressors affecting the ecosystem.

Fish communities were sampled using different nets at six nearshore and four offshore sites in eight and seven regions of the Peel-Harvey Estuary, respectively (MC, Mandurah Channel (nearshore only); EP, Eastern Peel; WP, Western Peel; NH, Northern Harvey; SH, Southern Harvey; SP, Serpentine River; LM, Lower Murray River and UM, Upper Murray River) during summer and autumn of 2023. As many fish as possible were returned to the water alive after they had been identified and counted. The resulting data on the abundances of each fish species from each sample were used to calculate a Fish Community Index score (0 – 100). These index scores were then compared to established scoring thresholds to determine ecological condition grades A (very good) to E (very poor) for each region and the estuary as a whole, based on the composition of the fish community. This method has been adopted annually for over a decade in Derbal Yirragan Djarlgarro (Swan-Canning Estuary) and has been shown to be a sensitive and robust tool for quantifying ecological health responses to local-scale environmental perturbations and tracking the subsequent recovery.

The WAMSI Westport Marine Science Program (WWMSP) is a $13.5 million body of marine research funded by the WA Government. The aims of the WWMSP are to increase knowledge of Cockburn Sound in areas that will inform the environmental impact assessment of the proposed Westport development and help to manage this important and heavily used marine area into the future. Westport is the State Government’s program to move container trade from Fremantle to Kwinana, and includes a new container port and associated freight, road and rail, and logistics. The WWMSP comprises more than 30 research projects in the biological, physical and social sciences that are focused on the Cockburn Sound area. They are being delivered by more than 100 scientists from the WAMSI partnership and other organisations.

The WAMSI Westport Marine Science Program (WWMSP) is a $13.5 million body of marine research funded by the WA Government. The aims of the WWMSP are to increase knowledge of Cockburn Sound in areas that will inform the environmental impact assessment of the proposed Westport development and help to manage this important and heavily used marine area into the future. Westport is the State Government’s program to move container trade from Fremantle to Kwinana, and includes a new container port and associated freight, road and rail, and logistics. The WWMSP comprises more than 30 research projects in the biological, physical and social sciences that are focused on the Cockburn Sound area. They are being delivered by more than 100 scientists from the WAMSI partnership and other organisations.

This report, commissioned by the Department of Biodiversity, Conservation and Attractions (DBCA), describes the monitoring and evaluation of fish communities in the Swan Canning Estuary during 2023 and applies the Fish Community Index (FCI) that was developed as a measure of the ecological condition of the estuary. This index, separate versions of which were developed for both the shallow (< 1.5 m), nearshore waters of the estuary and also for its deeper (> 1.5 m), offshore waters, integrates information on various biological variables (metrics). Each of these metrics quantifies an aspect of the structure and/or function of the fish community, and together they respond to a range of stressors affecting the ecosystem.

Fish communities were sampled using different types of net at six nearshore and six offshore sites in each of four management zones of the estuary (LSCE, Lower Swan Canning Estuary; CE, Canning Estuary; MSE, Middle Swan Estuary; USE, Upper Swan Estuary) during summer and autumn of 2023. As many fish as possible were returned to the water alive after they had been identified and counted. The resulting data on the abundances of each fish species from each sample were used to calculate a Fish Community Index score (0–100). These index scores were then compared to established scoring thresholds to determine ecological condition grades (A–E) for each zone and for the Swan Canning Estuary as a whole, based on the composition of the fish community.

This project investigates recreational and commercial fisher motivations for using a fishery and the beliefs, attitudes and perceived benefits of aquaculture-based enhancement programs and other management options. It also determines the total economic value for recreational fishing for Blue Swimmer Crabs (Portunus armatus) and Black Bream (Acanthopagrus butcheri) in a range of estuaries in south-western Australia and investigates the benefits of release programs in contributing to the optimisation of biological, social and economic objectives for those fisheries. Finally, it provides training for the next generation of fisheries and social scientists and fishery economists and project members engaged in community engagement and education.

Work was focused on two iconic small-scale estuarine fisheries in south-western Australia, i.e. those for Blue Swimmer Crabs and Black Bream. A two-phase approach to elicit common recreational fisher beliefs using semi-structured interviews (phase 1) and then sample a broader pool of respondents using closed-question online surveys (phase 2). Analyses demonstrated that motivations for recreational fishing were markedly different for the two fisheries, even when operating in the same system. Aquaculture-based enhancement was universally supported by the recreational sector as a fishery management approach as they believed it would enhance stocks and catches, and, although it may cause negative impacts, they were considered unlikely. Commercial fishers were less supportive of this management intervention. Enhancement of stocks was estimated to increase the economic value of recreational fishing through increased visitation. Biological modelling highlights that stocking could provide substantial benefits to the biomass of the target stocks, particularly Black Bream, but the parameters of any future stocking the need to carefully considered to ensure maximum benefits and the mitigation of density-dependent effects on wild stocks. Advice on the numbers and size-at-release for Blue Swimmer Crabs in the Peel-Harvey and Black Bream in the Blackwood River Estuary are provided to optimise the biological, social and economic dimensions of these fisheries.

This report, commissioned by the Department of Biodiversity, Conservation and Attractions (DBCA), describes the monitoring and evaluation of fish communities in the Swan Canning Estuary during 2021 and applies the Fish Community Index (FCI) that was developed as a measure of the ecological condition of the Swan Canning Estuary. This index, separate versions of which were developed for both the shallow, nearshore waters of the estuary and also for its deeper, offshore waters, integrates information on various biological variables (metrics). Each of these metrics quantifies an aspect of the structure and/or function of estuarine fish communities, and together they respond to a range of stressors affecting the ecosystem.

Fish communities were sampled using different nets at six nearshore and six offshore sites in each of four management zones of the estuary (LSCE, Lower Swan Canning Estuary; CE, Canning Estuary; MSE, Middle Swan Estuary; USE, Upper Swan Estuary) during summer and autumn of 2021. As many fish as possible were returned to the water alive after they had been identified and counted. The resulting data on the abundances of each fish species from each sample were used to calculate a Fish Community Index score (0–100). These index scores were then compared to established scoring thresholds to determine ecological condition grades (A–E) for each zone and for the estuary as a whole, based on the composition of the fish community.