The threatened status of shellfish reefs has been well established globally (e.g Beck et al 2011) however the ecological consequences of these losses is still largely unknown. In Australia, shellfish reefs are one of the most imperilled marine habitat types (Gillies et al 2018), due to historical overharvest and widespread eutrophication of coastal waters through the use of fertilizers, livestock and human waste. Marine bivalves are important ecosystem engineers providing habitat, shelter and a food source for other species in benthic soft-sediment environments. In addition, filter-feeding bivalves link benthic and pelagic components of ecosystems through filtration and excretion. Through their filter feeding, they produce large amounts of faeces (digested seston) and pseudofaeces (rejected particles bound up in mucus) which are deposited on the benthos. This process brings energy and nutrients from the pelagic system to the benthic system (bentho-pelagic coupling). The removal of large quantities of seston can serve an important ecosystem function by improving water quality and clarity. The filtration of water performed by bivalves has been demonstrated to reduce water turbidity, improving light penetration and thereby enhancing growing conditions for seagrasses (Wall et al 2008). In systems where healthy populations of bivalves remain, they can filter a volume equivalent or larger than the entire estuary volume within the residence time of the water (zu Ermgassen et al 2013). While such densities of oysters are rare today, this highlights the critical ecosystem services that are lost when oyster reefs decline. Furthermore, it demonstrates the potential functions that can be regained through oyster reef restoration. Given the increasing awareness of the decline of these ecosystems, interest in restoration efforts to restore critical ecosystem functions has been growing. However, conservation and restoration decision making is underpinned by reliable quantification of relevant ecosystem services (zu Ermgassen et al 2016). For example, there are plans to restore some of the natural oyster reefs of Sydney Rock Oyster (Saccostrea glomerata) in Port Stephens, New South Wales. One of the main drivers motivating this restoration project is restoring lost ecosystem services. The filtration rates of Australian oysters has been demonstrated in aquarium studies using filtered water augmented with algae, yet little is known about filtration and biodeposition rates of oysters using raw seawater. In this study, we provide the first evaluation of the filtration and biodeposition rate of four species of bivalves using raw seawater, providing a proxy for natural biodeposition rates. As such, this study provides a first indication of the filtration/nutrient cycling function that may be restored following oyster restoration efforts.

Data were collected by third-year students on a KSA324 field excursion down the D'Entrecasteaux Channel, on the IMAS vessel Noctiluca. The purpose of the trip was for students to learn how to collect various common types of oceanographic data and work on a research vessel. The study was designed to assess the impact of finfish farming in the Channel on local nutrient levels and water quality. The Tasmanian Environment Protection Authority (EPA) methods for water quality monitoring around finfish farms (Ford 2021, p. 6 – 18) were replicated as closely as possible. The null hypothesis for this study was that, on the 17/04/2023, all measured physico-chemical and biological factors were not significantly above the levels specified by the EPA guidelines (Ford 2021, p. 6 – 18), in any of the four stations measured. These four stations were chosen because they were all further than 35 metres beyond the boundary of any finfish farms’ Lease Area, as specified by the EPA guidelines document (Ford 2021, p. 6). The precise latitudes and longitudes of these stations are as follows: M1 (-43.059295, 147.345047); M2 (-43.056057, 147.291386); M3 (-43.123841, 147.290882); M4 (-43.133534, 147.326519). The dataset includes measurements of temperature, conductivity, oxygen concentration, pH, turbidity, fluorescence and pressure taken by the CTD rosette. Depth, density, practical salinity, absolute salinity and conservative temperature were derived and also included. The dataset also contains bottle sample measurements of oxygen, pH and alkalinity, as well as both the total and dissolved concentrations of ammonia, NOx, nitrite, phosphate and silicate. Chlorophyll concentration, total plankton cell counts, and counts of only Gymnodinium catenatum (a toxic, invasive dinoflagellate) cells were also included in the dataset. The dataset also contains the Secchi depth at each station. Empty cells are indicated by “NA”. ODV data flagging convention was used: 0 = good quality; 1 = unknown quality; 4 = questionable quality; 8 = bad quality. Reference: Ford, W (Director for the Environment Protection Authority) 2021, Environmental Licence No. 9869/3, Environmental Licence under the Environmental Management and Pollution Control Act 1994, pp. 6 – 18.

Carbon and nitrogen isotope data for J. edwardsii lobsters from eight sites in SE Australia.

Google Earth KMZ files of hammerhead sharks tagged with Wildlife Computers miniPAT archival tags and SPOT6 tags. Files of animals tagged with MiniPAT tags include an MELE polygon, which is the 'Maximum extent of location estimates', that is, a polygon enclosing all position estimates at the maximum error level (100 km). Collectively, movements are restricted within state waters with no hammerheads moving across state or International boundaries.