Policy and decision makers often seek guidance as to the benefits of conservation and repair of coastal seascapes, to justify and underpin any potential investments. Much is already known about the broad habitat and nursery values of seascapes among the science community, but there is also a need for estimation of clear and unambiguous market-based benefits that may arise from investment in repair. Recognising that this economic knowledge is imperfect for Australian seascapes, three case studies spanning tropical, subtropical and temperate environments explored the benefits in question. The case studies focus on saltmarsh habitats in particular, which have received very little investment in repair despite subtropical and temperate coastal saltmarsh listed as vulnerable ecological community under Australian Federal legislation. A subset of economically important species and conservative judgments were used to characterise the minimum potential economic benefit. For each of the case studies the conclusion was that while the biological information will remain imperfect, the business case for investment in the repair and conservation of coastal seascapes is compelling. We outline priorities for further research to make the business case more tangible to policy makers, stakeholders and the general public.

Adult and sub-adult Red handfish (Thymichthys politus) and Spotted handfish (Brachionichthys hirsutus) preserved specimens and underwater images were used for analysing morphometrics (comprising of specimens from the CSIRO Australian National Fish Collection and underwater images). Individuals were measured for the morphological traits using electronic callipers (±0.1 mm) for preserved specimens and using Image J software for digital records. Note digital image size calibration occurred using a ruler in images or from size taken in situ. The purpose was to investigate whether external morphometrics could be used to determine sex in handfishes.

The data describes number of vessels, engine power, gross tonnage and fishing effort by year (1950-2017), targeted functional group, and fishing gear. Fishing effort estimates were derived from country-level fishing fleet capacity data publicly available, following the method described in Rousseau et al (2019; https://doi.org/10.1073/pnas.1820344116) and methods improvement reported in Rousseau et al. (in prep). The data coverage is global, but estimates are given at the Exclusive Economic Zone-, Large Marine Ecosystem-, and Food Agriculture Organisation-level. The data was collected for a wide range of uses, including to inform global and regional marine ecosystem models and to understand the long-term evolution of fishing and its socio-ecological implications in the global ocean.

This submission creates a static snapshot of data from the Autonomous Underwater Vehicle (AUV) and stereo-BRUV annotation data from the National Environmental Science Program (NESP) Elizabeth and Middleton Reef survey. More details on the survey can be found at https://www.nespmarine.edu.au/document/elizabeth-and-middleton-reefs-lord-howe-marine-park-post-survey-report.

Interaction uncertainties between tidal energy devices and marine animals have the potential to disrupt the tidal energy industry as it advances. Best-practices for environmental impact assessments (EIAs) must be explored that are able to provide conclusive recommendations for mitigating environmental impact concerns of tidal energy developments. As the tidal energy industry is moving closer to commercial-scale array installations, the development of standardised EIAs would allow for potential impact concerns for the marine environment to be identified and minimised early in the site-development process. In an effort to help formulate a standardised EIA framework that addresses knowledge gaps in fish-current interactions at tidal energy candidate sites, this study investigated changes in fish aggregations in response to tidal currents at a tidal energy candidate site in Australia prior to turbine installation. Here, we present the dataset collected for this study that includes tidal current information from Acoustic Doppler Current Profiler (ADCP) measurements, volume backscattering strength from a four-frequency biological echosounder (Acoustic Zooplankton and Fish Profiler – AZFP) as an indicator for fish biomass, and fish aggregation metrics calculated from volume backscatter in post-processing. ADCP and AZFP were installed on a bottom-mounted mooring and engaged in a concurrent sampling plan for ~2.5 months from December 2018 to February 2019. The mooring was deployed in the Banks Strait, a tidal energy candidate site located in the northeast of Tasmania, Australia, at a location favourable for tidal turbine installations considering current speed, depth, substrate, sediment type and proximity to shore. The ADCP dataset includes current velocity and direction measurements at a 1 m vertical and 1-sec time intervals. The raw AZFP dataset includes volume backscattering strength collected at 4-sec time intervals with a vertical resolution of 0.072 m in raw, and 0.1 m in pre-processed form. Fish aggregation metrics were derived in post-processing and are presented by the minute along with corresponding environmental conditions for current speed, shear, temperature, diel stage, and tidal stage compiled from both AZFP and ADCP datasets.

Baited remote underwater stereo-video (stereo-BRUV) were used to sample the fish assemblages of the Hunter Marine Park and adjacent Port Stephens - Great Lakes Marine Park at equivalent depths. Stereo-BRUV were deployed in both autumn and spring from spring 2016 to autumn 2018 and at depth of 32-105m. The videos were analyse to all fish species to the lowest taxonmic level and estimate relative abundance (MaxN) and lengths of all species. This information was used to form a baseline of the benthic fish assemblages of the Hunter Marine Park. This study was done as part of the NESP Marine Biodiversity Hub D3 project (https://www.nespmarine.edu.au/project/project-d3-implementing-monitoring-amps-and-status-marine-biodiversity-assets-continental).