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Dylan Van Der Meulen
Role: 
PhD Candidate
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SIMS

 

 

Environmentally mediated spawning migrations of an estuarine dependent sillaginid


Understanding spawning cues and movement dynamics of fish is fundamental in determining which environmental and physical condition contributes to spawning success. Acoustic telemetry was used to examine the large scale (>1 km) movements of Sillago ciliata in two estuaries in southern NSW between 2009 and 2013. Movements were typified by regular rapid migrations, which would only occur during the spawning season, from upstream residences to locations adjacent to river entrances. Movements would consist of between 5 and 30 migrations across distances up to 50 kilometres. S. ciliata displayed high levels of fidelity for to both spawning locations and upstream residences. These spawning movements were followed by periods of decreased activity and reduced movement throughout the estuary. Further examination of movements during the spawning season showed that fluctuations in oceanic water temperature and increased freshwater flow triggered downstream migrations. Increases in oceanic water temperature during the spawning season are driven by strengthening of the EAC caused by southerly trade winds. We suggest that S. ciliata requires increased temperatures to progress larval development and strong northerly currents to aid in dispersal.

Supervisors: 

Professor Iain Suthers

Dr Matthew Taylor

Co-Supervisors: 

Dr Nick Payne

Dr Charles Gray

Dr Chris Walsh