Fish Health Unit

Teaching
We provide courses in fish health and production to students in the School of Veterinary and Life Sciences at Murdoch University. We also design and run training courses in Australia and overseas and provide a parasite diagnostic service. We have expertise in fish pathology, parasitology, aquaculture production, genetics and breeding, and environmental management. Recent training courses include a Fish Health Master Class in Bangkok, Thailand in 2007, a Fish Pathology Workshop at Murdoch University, in association with the World Association for Veterinary Parasitology Conference, and a Fish Disease Investigation Master Class in Ho Chi Minh City, Vietnam, in association with the 9th Diseases in Asian Aquaculture Symposium. The Crawford Fund and ACIAR have been generous supporters of our international training programs.

Murdoch Veterinary College students enjoy specialised training in fish health. Students get an opportunity to develop skills in fish disease investigations involving fish handling, anaesthesia, gill and skin biopsies and water chemistry tests as early as in their second year of training. As part of clinical rotations in their final year, greater in-depth knowledge in fish pathology and the art of disease investigations and health management are covered.

There is growing interests among veterinary and life sciences undergraduates in fish health. This is not surprising as there are growing opportunities for employment in the rapidly growing aquaculture sector and related industries in commercial fish feeds and pharmaceuticals, including vaccine production. In 2014, the Murdoch University Student Chapter of the World Aquatic Veterinary Medical Association (WAVMA) was formed. The first fish disease wet lab was very well attended, with 22 student participants. It is equally heartening to see an increasing number of our graduates, both from the Veterinary College as well as the School of Veterinary and Life Sciences, coming back to pursue postgraduate degrees in fish health and related disciplines.

If you wish to find out more about training opportunities in this field,
please contact Dr Susan Gibson-Kueh at S.Kueh@murdoch.edu.au.

Research projects

An introduced parasite on our native freshwater fishes

Thanks to funding from the Australian and Pacific Science Foundation, the Freshwater Fish Group & Fish Health Unit has been able to conduct research on the introduction of the exotic parasite, Lernaea cyprinacea, into our freshwater river systems. Within Western Australia’s Southwestern Province there are only 11 native freshwater species, with 9 limited to this area and many of these are threatened. Our native fish are generally very small in size and so even though they play a significant role in the health of our ecosystem they are often under appreciated.

Due to the destructive nature of invasive fish species, particularly with the co-introduction of exotic parasites, having an understanding of their impacts on our freshwater fishes becomes essential in the control and prevention of disease. With the release of goldfish into WA waters has come the co-introduction of L. cyprinacea. Unfortunately this parasite appears to have a high impact on the morbidity and mortality rate of our native fishes. Knowing and understanding why becomes crucial in the conservation of our native fishes. This project is determining the geographic range, prevalence and pathogenicity of the parasite L. cyprinacea on native fishes in the south-west. Mikayla McCredden’s PhD is submitted and examines the introduction of this exotic parasite.

Parasitism in wild and cultured fishes
Parasites can have a major effect on individual fishes and on fish populations. Melanie Koinari has recently completed her PhD on gastrointestinal protozoans (Giardia spp. and Cryptosporidium spp.) and anisakid nematodes in fish from aquaculture farms and fish markets in Papua New Guinea, the first time such a study has ever been done. While there was little evidence that parasites were causing health problems in the fish themselves, a number of zoonotic species were identified, posing a potential health risk to fish consumers. We have also continued our work, in collaboration with Una Ryan, on the taxonomy of Cryptosporidium spp. found in ornamental fishes in Australia. This is a complex storey, because of the great diversity of parasite genotypes that occur in fishes and the high prevalence. Jacqui Morgan is currently undertaking an Honours project on this topic.

Further reading:
Koinari, M., Karl, S., Elliot, A., Ryan, U.M. and Lymbery, A.J. (2013) Identification of Anisakis species (Nematoda: Anisakidae) in marine fish hosts from Papua New Guinea. Veterinary Parasitology 193: 126-133.

Koinari, M., Karl, S., Ng-Hublin, J., Lymbery, A.J. and Ryan, U.M. (2013) Identification of novel and zoonotic Cryptosporidium species in fish from Papua New Guinea. Veterinary Parasitology 198: 1-9.

Lymbery, A.J., Morine, M., Kanani, H.G., Beatty, S.J. & Morgan, D.L. (2014). Co-invaders: The effects of alien parasites on native hosts. International Journal for Parasitology: Parasites and Wildlife.

Enteric septicaemia of catfish: A threat to Australia’s biodiversity

Edwardsiella ictaluri is a bacteria that causes enteric septicaemia and encephalitis, and has caused mass mortality events in wild fish. Catfish species appear to be the most susceptible to E. ictaluri, however it can also affect many other fish species. The bacteria has recently been detected in Australia, in captive native catfish held in close proximity to imported ornamental fish. It has not been previously recorded in wild fish in Australia, but could pose a serious threat to our highly endemic fauna. This project is funded by FRDC Aquatic Animal Health Subprogram 2015/050, and has brought together researchers from the Freshwater Fish Group & Fish Health Unit (Murdoch University), CSIRO and TropWATER (James Cook University), Queensland Department of Agriculture, Fisheries and Forestry, Western Australian Department of Agriculture and Food, the Museum and Art Gallery of Northern Territory and Charles Darwin University to sample wild native catfishes from the Logan, Brisbane, Mary, Burnett, Pioneer, Ross, Tully, Barron, and Bloomfield rivers in Queensland, the Ord, Fitzroy and Ashburton rivers in Western Australia, and Rapid Creek and the Daly River in the NorthernTerritory.

In addition to testing these catfish samples for E. ictaluri, tissue samples were also taken to assess the general health of catfish, for parasite studies and to assist in a ranavirus survey with Sydney University. This has been one of the most extensive surveys of wild native catfish in Australia, in an attempt to determine the presence or absence of this serious bacterial pathogen. The project forms part of Erin Kelly’s Master of Philosophy studies that is supervised by Susan Kueh and Alan Lymbery, with collaborators including David Morgan (Murdoch University), Brendan Ebner, James Donaldson and Terry Miller (CSIRO and TropWATER (JCU)), Aaron Davis and Leo Foyle (James Cook University), Steve Brooks (Qld DAFF), Michael Hammer (MAGNT), Bertus Hanekom, David Crook (CDU), JR Albert (Nyikina-Mangala Rangers), James Keleher (MU) and Nicky Buller and Sam Hair (Department of Agriculture and Food, WA).

 

Carter’s Freshwater Mussel: a threatened species

The freshwater mussel Westralunio carteri occurs infreshwater rivers of south-western Australia. It is the only freshwater mussel found in this region, and the only member of the genus Westralunio in Australia. The mussel was classified as Vulnerable on the IUCN Red List of threatened species, but was de-listed in 2012. Michael Klunzinger recently completed his PhD on the ecology of this unique mussel. He described the life-cycle of the mussel for the first time and found that the distribution of W. carteri has severely contracted in the last 50 years because of their vulnerability to secondary salinisation and reduced water flow in rivers, the result of climate change. As a consequence, W. carteri has now been relisted as Vulnerable by the IUCN and as Threatened under the Western Australian Wildlife Conservation Act.

It is one thing to establish that a species is endangered, however, and quite another to develop a plan for its protection. There are still many unanswered questions about the life-cycle and habitat requirements of W. carteri that need to be answered before we can develop effective management plans. A new PhD student, Le Ma, is now taking up this challenge.

Further reading:
Klunzinger, M.W., Beatty, S.J., Morgan, D.L., Lymbery, A.J. & Haag, W.R. (2014) Age and growth in the Australian freshwater mussel, Westralunio carteri, with an evaluation of the fluorochrome calcein for validating the assumption of annulus formation.Freshwater Science 33: 1127-1135.

Klunzinger, M.W., Beatty, S.J., Morgan, D.L., Pinder, A.M. & Lymbery, A.J. (2015) Range decline and conservation status of Westralunio carteri (Iredale, 1934) (Bivalvia: Hyriidae) from south-western Australia. Australian Journal of Zoology.

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