Size in Square Kilometres
Qualifying Species and Criteria
Dugong – Dugong dugon
Criterion A; B (1); C (1; 2)
Australian humpback dolphin – Sousa sahulensis
Criterion A; B (1)
Australian snubfin dolphin – Orcaella heinsohni
Criterion A; B (1)
Marine Mammal Diversity
Megaptera novaeangliae, Tursiops aduncus, Tursiops truncatus
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The Hinchinbrook Channel to Round Hill IMMA network is formed by four sub-areas: 1) Keppel Bay to Round Hill, 2) Shoalwater Bay to Port Clinton, 3) Edgecumbe Bay to Repulse Bay, and 4) Hinchinbrook to Bowling Green Bay. The four sub-areas are characterised by shallow bays (<20m), turbid estuarine waters with extensive seagrass meadows and mangrove forests. Tides in this region are semidiurnal and tidal amplitude is generally below 4 m. Much of the land around three of the four sub-areas has been extensively modified for agriculture, grazing, ports, and industrial activities. The Shoalwater Bay to Port Clinton sub-area is much less modified as it is a Military Training Area. Extensive flooding is common in these regions during heavy rain and cyclones and terrestrial runoff causes problems with inshore water quality (Kroon et al. 2016). High levels of anthropogenic contaminants have been found in Australian snubfin dolphins and humpback dolphins (Cagnazzi et al. 2013a; Cagnazzi et al. 2020). Using the Hagihara method (Hagihara et al. 2018), the relative abundance of dugongs for the entire IMMA is ~2800 +/- SE 600 in 2016 (Marsh et al. 2019), so the region represents ~1% of the estimated global dugong population.. It is not appropriate to provide relative abundance estimates for the individual bays in the network because of the design of the survey and the movement of dugongs between bays. The dugong population in this IMMA has declined since 2005 (Marsh et al. 2019).
Description of Qualifying Criteria
Criterion A – Species or Population Vulnerability
The Hinchinbrook Channel to Round Hill network includes areas containing habitat important for the survival and recovery of three species listed internationally as Vulnerable on the IUCN Red List: Australian snubfin dolphins (Orcaella heinsohni), Australian humpback dolphins (Sousa sahulensis) and dugongs (Dugong dugon). In Australia all three species are considered Matters of National Environmental Significance as listed migratory species under the Environment Protection and Biodiversity Act 1999 (EPBC Act); Near Threatened in the Action Plan for Australian Mammals 2012 (Woinarski et al. 2014); and Vulnerable in Queensland, under the Nature Conservation Act 1992. In the Great Barrier Reef Marine Park, all three species are considered priority species for conservation under the Reef 2050 Long-Term Sustainability Plan (Commonwealth of Australia 2018) and the importance of the Great Barrier Reef as dugong feeding habitat is a reason for the region’s World Heritage Listing. Each of the sites within the Hinchinbrook Channel to Round Hill network includes Dugong Protection Areas A or B and additional extensive no-take zones (Dobbs et al. 2008). Dugongs are distributed widely along this coast. Three areas in the IMMA network, Hinchinbrook Island region, Cleveland Bay and Shoalwater Bay-Port Clinton, are consistently the most important dugong habitats in the IMMA, each supporting several hundred animals (Sobztick et al. 2017). Dugongs move between bays within this IMMA and between this IMMA and the Northern Great Barrier Reef IMMA and the Hervey Bay Great Sandy Straits IMMA (Sheppard et al. 2006; Gredzens et al. 2014). There is a significant genetic break in the Whitsunday Islands region (McGowan et al. in review). Satellite-tracked dugongs have not moved across this break, but the aerial survey data suggest that such movements occur (Sobtzick et al. 2017).
Criterion B: Distribution and Abundance
Sub-criterion B1: Small and Resident Populations
The Hinchinbrook Channel to Round Hill network includes habitat that supports resident populations of Australian humpback dolphins and Australian snubfin dolphins. Each resident population of snubfin and humpback dolphins consists of 50-150 individuals. Sightings of these dolphins between the residency areas are sparse, suggesting limited movement between the areas. Photo-identification studies within the areas indicate that each area is consistently occupied by individuals that are long-term residents (Parra et al. 2006; Cagnazzi 2010; Cagnazzi 2013; Cagnazzi et al. 2013b; Cagnazzi 2017). All dolphin species have been observed feeding regularly within this IMMA. All sub-areas include river mouths, large expanses of estuarine habitat and seagrass meadows that promote the presence of fish and cephalopod prey that Australian snubfin and humpback dolphins feed on (Parra and Jedensjö 2014). Analysis of genetic population structure for Australian humpback dolphins along the east coast of Queensland (Repulse Bay, Keppel Bay, Gladstone) showed generally low levels of genetic diversity, strong genetic structure, and limited contemporary gene flow (m < 0.1) (Parra et al., 2018). Genetic analyses of snubfin dolphin biopsies collected in Cleveland Bay, Fitzroy River/Keppel Bay and Repulse Bay/Whitsundays (~ 300 km apart) showed significant levels of population structure (Cagnazzi 2010). Contemporary migration rates per generation (20 years) between sampling locations are extremely low (< 10%, m < 0.1). Overall, the available genetic data suggest that humpback and snubfin dolphins along the east coast of Queensland exist as metapopulations of small and relatively isolated populations with limited gene flow. Criterion C: Key Life Cycle Activities
Sub-criterion C1: Reproductive Areas
The percentage of dugongs seen during the aerial surveys that have been classified as calves during the time series of aerial surveys (1974-2016) varied from zero in 2011 to 18% in 1999. Dugong fecundity is adversely impacted by food shortage and these fluctuations in percentage calves are due to the loss of seagrass caused by extreme weather events (Preen and Marsh 1995; Marsh et al. 2011; Fuentes et al. 2016). Dugongs have been observed calving in the inshore waters of this IMMA (Marsh et al. 1984).
Sub-criterion C2: Feeding Areas
The dugong is a seagrass community specialist (Marsh et al. 1982; Marsh et al. 2011; Marsh et al. 2018) and as a herbivore must spend much of its time feeding (Marsh et al. 2011). Dugong feeding plumes within the seagrass beds (Halophila ovalis) of the area are consistently seen in the area during aerial surveys, and are a critical part of this species survival with the Hinchinbrook Channel to Round Hill area.
Beasley, I., Golding, M. and Rangers, G. Looking for Palangal (dolphins) and Balangal (dugongs) in Girringun Sea Country-Unpublished report. (James Cook University, Townsville, 2013).
Beasley, I., Brooks, L., Parra, G. J. and Marsh, H. Evaluating Inshore Dolphin Conservation Status in Cleveland and Halifax Bays, North Queensland-Unpublished report. 11 (James Cook University, 2016).
Cagnazzi D. 2010. Conservation Status of Australian snubfin dolphin, Orcaella heinsohni, and Indo-Pacific humpback dolphin, Sousa chinensis, in the Capricorn Coast, Central Queensland, Australia In: School of Environment and Management, p. 194. Southern Cross University, Lismore.
Cagnazzi D. 2013. Review of Coastal Dolphins in central Queensland, particularly Port Curtis and Port Alma regions. p. 53, Gladstone Port Corporation, Queensland, Australia.
Cagnazzi D., Fossi M.C., Parra G.J., Harrison P.L., Maltese S., Coppola D., Soccodato A., Bent M. and Marsili L. 2013a. Anthropogenic contaminants in Indo-Pacific humpback and Australian snubfin dolphins from the central and southern Great Barrier Reef. Environmental Pollution 182, 490-4.
Cagnazzi D., Parra G.J., Westley S. and Harrison P.L. 2013b. At the heart of the industrial boom: Australian Snubfin dolphins in the Capricorn Coast, Queensland, need urgent conservation action. PLoS ONE 8, e56729.
Cagnazzi D. 2017. Increase understanding of the status of the Australian snubfin and humpback dolphins in Central Queensland: Mackay to Bowen. Final Report to The Australian Marine Mammal Centre (AMMC) of the Department of the Environment and Energy. Institute for Development, Environment and Sustainability (IDEAS), Marine Ecology Research Centre,Southern Cross University, Lismore, 2480, NSW.
Cagnazzi D., Harrison P.L., Parra G.J., Reichelt-Brushett A. and Marsili L. 2020. Geographic and temporal variation in persistent pollutants in Australian humpback and snubfin dolphins. Ecological Indicators 111, 105990.
Commonwealth of Australia 2018. Reef 2050 Long-Term Sustainability Plan (Access: July 2018)
Dobbs K., Fernandes L., Slegers S., Jago B., Thompson L., Hall J., Day J., Cameron D., Tanzer J., Macdonald F., Marsh H. and Coles R. 2008. ‘Incorporating dugong habitats into the marine protected area design for the Great Barrier Reef Marine Park, Queensland, Australia’. Ocean and Coastal Management 51, 368-75.
Fuentes M.M.P.B., Delean S., Grayson J., Lavender S., Logan M. and Marsh H. 2016. Spatial and temporal variation in the effects of climatic variables on dugong calf production. PLOS ONE 11, e0155675.
Gredzens C., Marsh H., Fuentes M.M.P.B., Limpus C.J., Shimada T. and Hamann M. 2014. Satellite tracking of sympatric marine megafauna can inform the biological basis for species co-management. PLOS ONE 9, e98944.
Hagihara R., Jones R.E., Sobtzick S., Cleguer C., Garrigue C. and Marsh H. 2018. Compensating for geographic variation in detection probability with water depth improves abundance estimates of coastal marine megafauna. PLoS One 13, e0191476.
Kroon F.J., Thorburn P., Schaffelke B. and Whitten S. 2016. Towards protecting the Great Barrier Reef from land-based pollution. Global Change Biology 22, 1985-2002.
Marsh H., Channells P., Heinsohn G. and Morrissey J. 1982. Analysis of stomach contents of dugongs from Queensland. Wildlife Research, 9: 55-67.
Marsh, H., Heinsohn, G. E. and Marsh, L.M. 1984. Breeding cycle, life history and population dynamics of the dugong, Dugong dugon Sirenia: Dugongidae. Australian Journal of Zoology, 32: 767-785.
Marsh H., O’Shea T.J. and Reynolds J.E. 2011. Ecology and conservation of the Sirenia: dugongs and manatees (Vol. 18). Cambridge University Press.
Marsh H., Grech A. and McMahon K. 2018. Dugongs: seagrass community specialists. In: A. Larkum, G. Kendrick, P., Ralph. (eds) Seagrasses of Australia. Springer International . Available at: DOIhttps://doi.org/10.1007/978-3-319-71354-0_19. (Accessed: 27 June 2020)
Marsh, H., Hagihara, R., Hodgson, A., Rankin, R., and Sobtzick, S. 2019. Monitoring dugongs within the Reef 2050 Integrated Monitoring and Reporting Program: final report of the Dugong Team in the Megafauna Expert Group. Great Barrier Reef Marine Park Authority, Townsville. Available at: http://elibrary.gbrmpa.gov.au/jspui/bitstream/11017/3583/4/RIMReP%20Dugong%20rport.pdf. (Accessed: 27 June 2020)
McGowan A.M., J.M. L., Clark N., Blair D., Marsh H., Wolanski E. and Seddon J.M. in review. Seascape genetics of a mobile marine mammal: evidence of an abrupt break in dugong (Dugong dugon, Müller) gene flow along Australia’s eastern Queensland coast. Conservation Genetics.
Parra G.J., Corkeron P.J. and Marsh H. 2006. Population sizes, site fidelity and residence patterns of Australian snubfin and Indo-Pacific humpback dolphins: Implications for conservation. Biological Conservation 129, 167-80.
Parra G.J. and Jedensjö M. (2014) Stomach contents of Australian snubfin (Orcaella heinsohni) and Indo-Pacific humpback dolphins (Sousa chinensis). Marine Mammal Science 30, 1184-98.
Parra G.J., Cagnazzi D., Jedensjö M., Ackermann C., Frere C., Seddon J., Nikolic N. and Krützen M. 2018. Low genetic diversity, limited gene flow and widespread genetic bottleneck effects in a threatened dolphin species, the Australian humpback dolphin. Biological Conservation 220, 192-200.
Preen A. and Marsh H. 1995. Response of dugongs to large-scale loss of seagrass from Hervey Bay, Queensland, Australia. Wildlife Research 22, 507-19.
Preen, A. 2000. Dugongs, boats, dolphins and turtles in the Townsville-Cardwell region and recommendations for a boat traffic management plan for the Hinchinbrook Dugong Protection Area. (Great Barrier Reef Marine Park Authority, 2000).
Sheppard J.K., Preen A.R., Marsh H., Lawler I.R., Whiting S.D. and Jones R.E. 2006. Movement heterogeneity of dugongs, Dugong dugon (Muller) over large spatial scales. Journal of Experimental Marine Biology and Ecology 334, 64-83.
Sobtzick S., Cleguer C., Hagihara R. and Marsh H. 2017. Distribution and abundance of dugong and large marine turtles in Moreton Bay, Hervey Bay and the southern Great Barrier Reef. A report to the Great Barrier Reef Marine Park Authority. Centre for Tropical Water and Aquatic Ecosystem
Research (TropWATER) Publication 17/21, James Cook University, Townsville.
Woinarski J., Burbidge A. and Harrison P. 2014. Action Plan for Australian Mammals 2012. CSIRO Publishing, Collingwood, Victoria, Australia.