Marsh, H., Grech, A., Miller, R., and Collins, K. (2020) An assessment of the distribution and abundance of dugongs and large in-water turtles in Cleveland Bay and adjacent bays to provide baseline information for the Port of Townsville Channel Upgrade Project: a report for the Port of Townsville Limited. Report. TropWATER, James Cook University, Townsville, QLD, Australia.

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Abstract

We conducted standarised aerial surveys of Bowling Green, Cleveland and southern Halifax Bays to assess the distribution and abundance of dugongs and in-water large marine turtles in winter (June) and early summer (November) 2019, prior to the start of the capital dredging for the Port of Townsville Channel Upgrade (CU) project.

The aerial surveys design used here was developed for regional scale surveys and the precision of the population estimates at a local scale is low. Comparison of the results of the 2019 surveys with the results of similar surveys conducted by Marsh’s team at JCU, as part of their long-term series of regional surveys, confirmed marked inter-annual differences in the estimated dugong population in Cleveland-southern Halifax Bays. These differences reflect temporal variations in the status of seagrass in the region as revealed by the annual surveys conducted by the JCU Seagrass Ecology Group since 2007. The estimate of relative abundance of dugongs in the survey region in November 2019 was ~500 (+ se 140).

Detecting the local-scale impacts of a development on dugongs and large turtles in a construction timeframe is likely to be impossible, unless the impact of the development on the animals is catastrophic. Consequently, it would be more useful for the Port Authority of Townsville to fund research on marine megafauna and proxy studies on water quality and seagrass rather than to attempt to monitor the direct impacts of the CU project on megafauna. Such studies have the potential to inform management of long-term impacts on the megafauna in the face of extreme weather events.

Item ID:	81042
Item Type:	Report (Report)
Keywords:	dugongs, turtles, Cleveland Bay, baseline, assessment, Port of Townsville, channel upgrade
Copyright Information:	© James Cook University, 2020.
Funders:	Port of Townsville Limited
Date Deposited:	23 Nov 2023 04:30
FoR Codes:	41 ENVIRONMENTAL SCIENCES > 4199 Other environmental sciences > 419999 Other environmental sciences not elsewhere classified @ 100%
SEO Codes:	18 ENVIRONMENTAL MANAGEMENT > 1899 Other environmental management > 189999 Other environmental management not elsewhere classified @ 100%
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