Project number: 2000-159
Project Status:
Completed
Budget expenditure: $277,687.00
Principal Investigator: Ian Potter
Organisation: Murdoch University
Project start/end date: 10 Sep 2000 - 9 Oct 2004
Contact:
FRDC

Need

The urgent need for reliable quantitative data on the habitats which are used extensively by commercial and recreational fish species during one or more stages in their life cycles has been highlighted by Cappo et al. (1998) in their report to FRDC (95/055). That report identified a deficiency in a knowledge of the following:

1. Characteristics and locations of important fisheries habitats at scales useful for research and management.
2. Life history information for fish species, related to the types of habitats occupied throughout their life cycles, and data on the densities and/or biomass of those other biotic components of fish habitats, which provide food and/or protection for fish, such as invertebrates and aquatic vegetation.
3. Habitat dynamics and ecosystem processes, including food webs, habitat use and fisheries production in soft sediment substrata, such as beaches.
4. Fisheries-habitat links, including the influences of hydrodynamic and other processes on the recruitment of commercial and recreational fish species.

The above gaps in our knowledge were also highlighted by the FRDC in its “Research Priorities for Fisheries Ecosystem Protection”, when they listed two of its strategic R&D areas as “defining major habitats in the coastal exclusive economic zone” and “the roles of habitats in maintaining healthy fisheries production, ecosystem integrity and biodiversity”.

There is a particularly urgent need to fill the above gaps because the coastal and estuarine waters of Australia are becoming increasingly exposed to the effects of numerous coastal developments, e.g. the construction of harbours, marinas and groynes, and to the destruction of habitat through other forms of activity, e.g. dredging for sand and extreme forms of eutrophication. Information on which habitats are most important to commercial and recreational fish species in these waters are required by managers so that they can introduce appropriate plans for managing and conserving those habitats.

Objectives

1. Define quantitatively the range of habitat types found in nearshore marine and estuarine waters in south-western Australia.
2. Determine the compositions of the benthic macroinvertebrate faunas at sites representing the different habitat types and ascertain the extent to which such data help refine the criteria for defining the different habitat types.
3. Determine the compositions of the fish faunas in representative examples of the different habitat types, and thereby determine which habitats are "preferred" by each of the main commercial and recreational fish species.
4. Develop a suite of characteristics which can thus be used to predict which fish species will be found in each of the different types of habitat.
5. Determine, for a moderately sheltered and a moderately exposed coastal habitat, and a habitat in the Swan Estuary, the abundance, biomass and size composition of the main components of the diets of fish species and of the potential prey of those species in the benthos and water column. These data will be used to determine the most important prey for each of the abundant fish species and to construct a preliminary food web.
6. Collate the key components of the data collected by this study in a form that will enable fisheries and environmental managers to ensure that those areas of the coast that provide crucial habitats for important fish species are protected from deleterious anthropogenic activities.

Final report

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