The importance of parasites in the conservation of native freshwater fish

A project undertaken at Murdoch University, Perth and supervised by Alan Lymbery

Western Australia has a very high percentage of endemic freshwater fish species, threatened by anthropogenic impacts such as the salinisation of rivers and the introduction of exotic plants and animals. Understanding the parasite fauna of freshwater fish can potentially provide valuable information about these threatening processes. The general aim of this project is to demonstrate how a study of the parasites of freshwater fish in the south west of Western Australia can assist in the protection and restoration of native fish populations.

The specific objectives of the study are to:

  • Identify parasites in native and exotic freshwater fish species in the south west of Western Australia.
  • Determine prevalence, intensity of infection and pathology of infection for each parasite species in each host species.
  • Determine whether parasite load of native freshwater fish is greater in the presence of exotic fish species.
  • Estimate the threat posed to the conservation of native freshwater fish by natural and introduced parasites.
  • Measure the effect of salinity on prevalence and intensity of infection for each parasite species in each host species.
  • Establish the value of parasite data as an indicator of salinisation.
Publications

Hassan, M, S J Beatty, D L Morgan, R G Doupe & A J Lymbery (2008). An introduced parasite, Lernaea cyprinacea L., found on native freshwater fishes in the south west of Western Australia. J. Roy. Soc WA, 92: 149 - 153.

Hassan, M, B Jones & A J Lymbery (2009). A new species of Dermoergasilus Ho & Do, 1982, (Copepoda: Ergasilidae) from freshwater fishes in the south-west of Western Australia. Syst Parasitol. 74: 143 - 148.
(DOI 10.1007/s11230-009-9217-3)

Lymbery, A J, M Hassan, D L Morgan, S "J Beatty and R G Doupé (2010). Parasites of native and exptic freshwater fishes in south-western Australia. J. Biol. 76, 1770 - 1785.

Hobbs, R P and M, Hassan (2010). Pseudocapillaria (Icthypcapillaria) nannupensis n. sp. (nematoda: Capillariidae) from the intestine of the freshwater coppler Tandanus bostocki (Plotosidae) from southwestern Australia. Comp. Physiol. 77: 20 - 24.

 

Figure 1. A native freshwater fish species, Galaxias truttaceus

Figure 2. A fish infected with the tapeworm Ligula intestinalis

Figure 3. A close up of the anterior end of the parasite (Ligula intestinalis)

Figure 4. Trematode metacercariae (unidentified species) in skin of western minnow (Galaxias occidentalis).

Figure 5. Nematode, Eustrongyloides sp. under skin of western minnow (Galaxias occidentalis).

Figure 6. Anchor worm, Lernea sp., attached to freshwater cobbler (Tandanus bostocki).

Figure 7. Tapeworm, Ligula intestinalis, infecting the common jollytail (Galaxias maculates).