Threatened and migratory species scoping study

This project provides guidance for future research in priority species, including marine mammals and seabirds. Sub-projects led by different hub partners reviewed and inventoried existing data and publications and consulted researchers and research users from state and federal governments, community and industry groups and non-government organisations.

An inventory of dugong aerial surveys across Australia includes relevant publications, data availability and location, maps of the survey effort to date, and compares approaches of generating population estimates, trends and spatial distribution models. It identifies preferred research pathways and methodologies.

An exploration of research priorities for threatened seabirds and marine mammals (excluding dugongs) reviewed publications and consulted researchers and research users. Priorities included monitoring to support population estimates, linking at-sea behaviours, population trends and ecological change, integrated risk assessment, identification and use of new technologies and novel approaches, risks associated with offshore renewable energy development; and best practice data management.

Approach and findings

Sub-project: An inventory of dugong aerial surveys in Australia

The dugong (Dugong dugon) has significant cultural, ecological and conservation value in Australia. The species is a Matter of National Environmental Significance and is protected under the Environment Protection and Biodiversity Conservation Act 1999 as a listed migratory and marine species. Since the early 1970s various aerial surveys have provided data on the distribution and abundance of the dugong across northern Australia. The survey design, platforms, and methods to estimate dugong population distribution, abundance, and trends, have evolved through time, and much of the survey data and related publications were fragmented and inaccessible.

This sub-project compiled information from all dugong aerial surveys undertaken since the first use of aerial surveys for dugongs in Australia, including date of survey, approach undertaken to survey, latest abundance estimate, relevant reference and link to publication, data availability and location. It mapped survey effort across the known dugong range. The inventory has helped identify similarities and discrepancies in how dugong population estimates, trends and spatial distribution models have been generated.

Dugong aerial surveys in Australia dating back to the early 1970s assessed the presence, distribution, and relative numbers of dugongs around the mainland and islands. Standardised abundance aerial surveys began in the early 1980s and have covered most inshore waters from Shark Bay in Western Australia to Moreton Bay near Brisbane. These range from single baseline surveys (such as in the Kimberley area) to frequently surveyed areas, such as the Exmouth Gulf (15 surveys to date) and the Darwin region (22 surveys to date). The high number of surveys in the latter regions mostly reflects industry-funded programs in areas potentially impacted by coastal development activities. These surveys add to regional dugong population assessment surveys conducted every few years.

Mathematical approaches to account for imperfect detections of dugongs in abundance estimations have evolved through time. The Hagihara method is the most nationally accepted standard and was used in 2019 to retrospectively re-estimate dugong abundance for all surveys conducted in Eastern Queensland since the early 2000s. Similar work should be conducted on historical survey data collected in other parts of Australia to aid data comparison and calibration for population trend analysis. Similarly, approaches to assess trends in dugong populations vary across regions and survey events. Providing available data; efforts should be made to harmonise trend analysis across the country (using frequentist statistics and new Bayesian models).

Varying approaches have been used to model the density distribution of dugongs using aerial survey data, but there has not been an evaluation of how these methods differ or which could be adopted as a national standard to enable comparability of results.

The likelihood of securing funding to increase the number of surveys in large remote areas such as the Kimberley to obtain the time series necessary for population trends analysis is low. In those instances, cheap, user-friendly and culturally appropriate new approaches should be considered for sea country monitoring led by Ranger groups.

Sub-project: Seabirds and marine mammals (excluding dugongs)

Outcomes

The inventory and review of dugong aerial survey research across Australia provided by this project is an important step towards developing Australia’s capacity to estimate dugong population and trends. It provides the Department of Department of Climate Change, Energy, the Environment and Water guidance on future investment relating to this priority species.

The collation of existing knowledge and consultation with stakeholders to identify priority research areas for seabirds and marine mammals (excluding dugongs) provides a shared understanding among researchers and decision-makers and a pathway to maximising the relevance and effectiveness of future research in this area.

Involvement of a range of end-users in a considered planning, consultation and prioritisation process strengthens the likelihood of on-ground outcomes and long-term adoption.

Project location

National