Michelle M. Dennis
Australian marine animal populations have had no shortage of emerging diseases, often influenced by natural or anthropogenic environmental stress factors, translocation of infected hosts into naïve populations, population migrations, movement of water or fomites, and convergence with cultured aquatic animal ecosystems. Causal factors remain to be elucidated with several recently emerged diseases. From 2007–2011, an epidemic of mortality due to Streptococcus agalactiae septicemia was observed in 93 giant Queensland grouper in northern Queensland.1 Subsequently, two separate mortality epidemics in 2009 and 2010, also due to S. agalactiae septicemia, were observed in five species of wild-caught captive stingrays in an aquarium at Sea World, Queensland. Some of these stingrays were sourced from areas where grouper mortality was observed. Cetacean morbillivirus is another emerging pathogen. Although it is thought to have been endemic in Australian cetaceans since at least the mid-1980s,2 mortality events were only first described in offshore bottlenose dolphins stranded on Queensland coastline in 20113. In 2013, morbillivirus-associated mortality was observed in inshore and offshore bottlenose dolphins stranded on South Australian coastline, and was later retrospectively demonstrated in inshore bottlenose dolphin deaths, which occurred in the Swan River, Western Australia, in 2009.4 Another emerging marine disease issue in Australia, which has received considerable attention from the mainstream press, comprises an aquatic ecosystem health crisis occurring from 2011 to present, associated with a monumental scale dredging project of the Gladstone harbour, at the interface with the Great Barrier Reef Marine Park and World Heritage Area. Epizootics of mortality were concurrently observed in several species of teleosts, elasmobranchs, crustaceans, bivalves, sea turtles, dugongs, and cetaceans.5,6 A scientific approach to understanding this disease event is crucial for informing policy-making, as several large scale port expansion proposals within or adjacent to the Great Barrier Reef Marine Park are currently underway. Further research is needed to better understand the factors influencing each of these Australian emerging marine health issues.
1. Bowater RO, Forbes-Faulkner J, Anderson IG, Condon K, Robinson B, Kong F, Gilbert GL, Reynolds A, Hyland S, McPherson G, O'Brien J, Blyde D. Natural outbreak of Streptococcus agalactiae (GBS) infection in wild giant Queensland grouper, Epinephelus lanceolatus (Bloch), and other wild fish in northern Queensland, Australia. Journal of Fish Diseases. 2012;35:173–186.
2. Stone BM, Blyde DJ, Saliki JT, Morton JM. Morbillivirus infection in live stranded, injured, trapped, and captive cetaceans in southeastern Queensland and northern New South Wales, Australia. Journal of Wildlife Diseases. 2012;48:47–55.
3. Stone BM, Blyde DJ, Saliki JT, Blas-Machado U, Bingham J, Hyatt A, Wang J, Payne J, Crameri S. Fatal cetacean morbillivirus infection in an Australian offshore bottlenose dolphin (Tursiops truncatus). Australian Veterinary Journal. 2011;89:452– 457.
4. Stephens N, Duignan PJ, Wang J, Bingham J, Finn H, Bejder L, et al. Cetacean morbillivirus in coastal Indo-Pacific bottlenose dolphins, Western Australia. Emerging Infectious Diseases. 2014 Apr [date cited].
5. Landos M. Investigation of the causes of aquatic animal health problems in the Gladstone Harbour and nearshore waters, Future Fisheries Veterinary Service and Gladstone Fishing Research Fund, 2012. Accessed Mar 2014 at: http://www.gladstonefishingresearchfund.org.au
6. Gladstone fish health scientific advisory panel Final Report, 2012. Accessed Mar 2014 at: www.ehp.qld.gov.au/gladstone/pdf/gladstone-sap-report.pdf