Life Histories of NSW Marine and Estuarine Fishes

In NSW, we know the life histories and habitat requirements for few species. It is the goal of this project to help fill those gaps. In short, this project involves systematic, ecological and behavioural research.

Research Scientists: Jeff Leis & Tom Trnski

Nearly all marine bony fishes that occur in New South Wales marine and estuarine waters have a pelagic larval stage. Usually, the larvae occupy different habitats than do the adults. Take for example the Blue Groper that lives on a reef. The larvae can be found in the open waters of the continental shelf, older larvae may be found near the shore and estuarine channels, and the juveniles occur in nurseries in estuarine seagrass beds.

This chain of habitats is essential for the completion of the life cycle of the fish: if any link is broken - for example by habitat degradation or destruction - the species is doomed. During their pelagic stage, larvae may be dispersed between habitats primarily by currents, or their own behaviour may have a large influence on their dispersal. To properly and sustainably manage these fish populations, we need to know what the required habitats are, and how the movements between them take place.

In NSW, we know the life histories and habitat requirements for few species. It is the goal of this project to help fill those gaps. To this end, the following subjects are under study:

• Identification of larvae - adults and larvae differ greatly in morphology, and the larvae of many species remain unidentified. We are describing the larvae of Australian Bass, Estuary Perch, Eastern Australian Eastern Blue Groper, Sargent Baker, Matsubara's velvetfish, and others.
• Identification of larval habitats - by targeted plankton sampling and examination of collections held in the Regional Larval Fish Archive (view procedures manual (pdf 161k) at the Australian Museum we are identifying the areas where the larvae may live during their pelagic phase.
• Identification of larval behavioural capabilities - we use larvae reared by aquaculturalists to determine the swimming capabilities of the larvae of a number of important commercial and sport species including Mulloway, Snapper, Bream and Australian Bass. This will enable us to determine the extent to which these larvae are able to control their dispersal.

In short, this project involves systematic, ecological and behavioural research.

This project is supported by an Enhancement Grant by the NSW Government and by the Australian Museum. It involves collaboration with Dr Stewart Fielder of NSW Fisheries, Mr Glenn Searle of Searle Aquaculture, Dr Tony Miskiewicz of Wollongong City Council, and Museum staff, Ms Domine Clark, Ms Amanda Hay, Mr Matthew Lockett and Ms Sally Reader.

Papers resulting in whole or in part from this project (more are in progress):

1. Clark 2002. The ontogeny of swimming performance in the larvae of two temperate marine fish species: Argyrosomus japonicus and Pagrus auratus. Honours Thesis, School of Marine and Coastal Studies, University of New South Wales. 55pp.
2. T Trnski 2003. Physical and behavioural determinants of settlement success in fishes that use estuaries as juvenile nurseries. PhD Thesis, University of Technology, Sydney.
3. JM Leis & AC Hay (submitted) Larval development of Achoerodus viridis (Pisces: Labridae), the Australian Eastern Blue Groper.
4. T Trnski, AC Hay & S Fielder (in prep) Larval development of the Australian Bass and Estuary Perch (Pisces: Percichthyidae).
5. JM Leis, SE Reader and T Trnski (in prep) The use of central NSW surf zones by larval fishes.