The 2019 QUEX PhD candidates are working on the following projects. Please note, these positions have been filled.

4. Examining trajectories of decline of megafauna in our coastal seas

UQ academic lead

Professor John Pandolfi, Professor, School of Biological Sciences

Exeter academic lead

Dr Ruth H. Thurstan, Centre for Ecology and Conservation, College of Life and Environmental Sciences

Project description

Our coastal seas have been degraded by centuries of human use. Although few global extinctions have been documented, large fish species such as sharks, sawfish, groupers and sturgeon used to be much more abundant in coastal seas compared to today. Local extinctions have occurred in numerous regions, and where populations exist they are much reduced compared to the past.

In most cases, declines of these animals commenced long before scientific monitoring began, making it difficult to establish the true extent of loss prior to significant human impacts. Without improving our understanding of past abundance and distribution, we risk overlooking the seriousness of continued declines. Without historical baselines, we cannot set appropriate recovery targets or accurately assess the risk of extinction to remaining populations.

Where monitoring data do not exist, alternative sources can help us understand trajectories of change over time. Marine historical ecology uses interdisciplinary approaches, pulling together data from archaeological, archival and local ecological knowledge sources, among others, to unravel historical patterns and drivers of change in species abundance and distribution.

The iconic nature of these fish species meant that a capture or sighting would often be communicated to the community via popular media or by word of mouth. Photos or parts of these fish would also often be kept as mementoes by those who captured them. In recent years, the rapid digitisation of archival data, particularly popular media such as newspaper accounts, has made huge quantities of previously unseen historical material readily searchable (e.g. TROVE). The development of novel statistical techniques has also enabled hypotheses about population trajectories to be tested using sparse or sporadic data. These two developments provide a timely opportunity for furthering our understanding of the risks posed to large iconic species and will aid marine managers in setting more accurate targets for their recovery.

This study will merge interdisciplinary methodologies and disparate historical sources to:

  1. determine the historical distribution of large coastal fish species
  2. establish historical trajectories in sightings/capture and last-known occurrence
  3. estimate observer trends over the period of historical observation
  4. estimate population trajectories and compare across species and regions.

The joint nature of this project will enable an initial broad focus on this global and highly topical issue, with the student ultimately choosing specific locations in Australia and the UK to conduct detailed investigations. Case studies will be chosen to allow multi-factorial investigations of multiple species, with the aim to compare observed trajectories across regions with differing human densities, fishing and coastal development histories. Both Australia and the UK have extensive digitised archive collections. However, in contrast to the long history of decline in UK waters, large species such as groper and sawfish continued to be sighted in coastal tropical Australia until recently, hence the student will also use local ecological knowledge to generate data from this region.