Smith, Caitlin E., Finlayson, Kimberly, Madden, Claire, Young, Erina J., and Van De Merwe, Jason (2026) Disease presence and dietary shifts in green turtles following extreme flooding events. In: Proceedings of the 44th Symposium on Sea Turtle Biology and Conservation. p. 26. From: 44th Symposium on Sea Turtle Biology and Conservation, 28 February - 6 March 2026, Kailua-Kona, HI, USA.

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Abstract

Climate change is intensifying extreme weather events, increasingly impacting coastal regions and their marine ecosystems. In Hervey Bay, Queensland, severe flooding in 2021 was linked to a marked reduction in seagrass coverage, a surge in green turtle (Chelonia mydas) strandings, and the emergence of a previously undocumented condition known as soft shell syndrome. In response, a comprehensive health assessment of the local green turtle population was funded by the Commonwealth-state Disaster Recovery Funding Arrangements (DRFA). A total of 145 individuals were evaluated through physical examinations, blood sampling for health and toxicology, and gastric lavage for dietary analysis. A popular hypothesis prior to the investigation was that the observed health deterioration was linked to a dietary shift from seagrass to alternative forage sources such as mangrove and algae. Findings revealed that sub-adults and adult males were disproportionately in poorer health and body condition, likely due to age-specific dietary patterns. Juvenile turtles, with a more diverse diet, exhibited greater resilience. Lavage samples from subadults contained higher proportions of mangrove species Avicennia marina and Rhizophora stylosa, as well as algae, compared to adults. Notably, juveniles with higher body condition scores frequently consumed the red alga Catenella nipae, which was the most prevalent and abundant dietary item across samples. Contrary to initial hypotheses, these results suggest that dietary flexibility, particularly the ability to shift to mangrove and algal resources during seagrass dieback, may mitigate susceptibility to chronic illness and disease, and is not the cause of poor health. However, the lack of baseline data on diet composition and health metrics for this population limits the ability to contextualise these findings. We recommend ongoing, holistic monitoring of the Hervey Bay green turtle population during non-disturbance periods to establish reference conditions. This will enhance conservation strategies and improve resilience planning in the face of increasing anthropogenic pressures and climate-driven extreme weather events.

Item ID:	93645
Item Type:	Conference Item (Abstract / Summary)
ISSN:	3106-1397
Date Deposited:	18 Aug 2026 23:54
FoR Codes:	31 BIOLOGICAL SCIENCES > 3103 Ecology > 310303 Ecological physiology @ 50% 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 50%
SEO Codes:	19 ENVIRONMENTAL POLICY, CLIMATE CHANGE AND NATURAL HAZARDS > 1999 Other environmental policy, climate change and natural hazards > 199999 Other environmental policy, climate change and natural hazards not elsewhere classified @ 50% 18 ENVIRONMENTAL MANAGEMENT > 1805 Marine systems and management > 180599 Marine systems and management not elsewhere classified @ 50%
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