Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

Effect of fluke metacercariae on Murray cod survival behaviour  (#38)

Leia Rogers 1 , Raf Freire 1 , Shokoofeh Shamsi 1 , Paul Humphries 1 , R Keller Kopf 2
  1. School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Albury, NSW, Australia
  2. Charles Darwin University, Darwin

In natural and artificial aquatic environments, parasites are ever-present in the body systems of fish. Parasites can jump from a variety of hosts in an ecosystem, moving to different species to develop into the next stages of their life cycle. Parasites can influence the behaviour of their infected host in various ways, such as through the exhaustion of the host’s energy stores and adaptive manipulation but can also be seen in fish behaviour depending on what body system the parasite has targeted. In order to determine if parasites cause changes in behaviour, infection status need to be manipulated in the laboratory. We first investigated if a keystone native freshwater fish species, Murray cod, can be infected in a laboratory environment with a recently discovered parasitic fluke species found in the Murray-Darling basin. Secondly, we examined the effect of parasite infection on the fish’s survival behaviour by running a series of four behavioural tests; latency to emerge, latency to explore, habitat choice and predator avoidance from fish-eating birds and fish. The parasitic load and locations of the parasite were then analysed in the fish, and parasite-induced changes in behaviour were determined.  Revealing this parasite’s lifecycle and influence on host behaviour and physiology has given a better understanding on the costs of parasite infection to a fish host and its ecosystem. The information gathered will additionally aid in providing information to Murray-Darling Basin Fisheries who release high numbers of these fish into the basin’s ecosystem annually.