Successful management of a fishery for any species requires a thorough understanding of how that species will respond to different levels of exploitation. Such an understanding depends on managers possessing certain crucial biological data that have been acquired using an appropriate sampling regime, laboratory techniques and analysis of the results. The key biological data that are required for a species are as follows: (a) age and size compositions, growth curves and age and length at maturity for both sexes, (b) length and age at sex change in the case of hermaphroditic species, (c) location and duration of spawning, (d) fecundity and (e) estimates of mortality. These data enable scientists to assess the status of the stock(s) and thereby provide advice to managers, who are then in a strong position to formulate appropriate management strategies.

The following three species have been identified as “indicator” species for management purposes: western blue groper Achoerodus gouldii, queen snapper Nemadactylus valenciennesi and bar-tailed flathead Platycephalus endrachtensis (Fisheries Management Paper 153; Report of 2003 RFAC/RecFishWest research planning meeting). However, there are no reliable data on the crucial biological characteristics listed above for any of these species in Western Australian waters (e.g. FishBase). Managers thus require these data for management purposes.

Since the results of many of the age and growth studies of fish species in various regions are not of the standard required to produce reliable data for management purposes, there is a need to produce guidelines on the extent and quality that are required of such studies for management purposes.

Freshwater allocations to sustain fisheries

The 1994 COAG Water Reform Agreement and various state legislation (e.g. Water Act 2000 in Queensland) requires managers to allocate water to maintain downstream ecosystem health. One aspect of ecosystem health is estuarine and coastal fisheries production. Information on the role of freshwater in maintaining the productivity of commercial and recreational fisheries is needed to ensure that estuaries and their stakeholders are duly represented in the water allocation processes. Natural resource managers (fisheries and water) need to be made aware of the fishing industry’s vulnerability to the impacts of non-fishing activities, such as water regulation. This issue has been identified as a challenge for the fishing industry in reaching sustainable production (see Challenge 1 of FRDC’s R&D Plan 2000, page 59).

Logical frameworks for research leading to new procedures and methods

A logical framework needs to be developed for investigating the role of freshwater flows in estuaries. Procedures to assess the impacts of current and proposed water infrastructure in Australian coastal rivers on estuarine fisheries need to be developed. Methods for monitoring biological responses to environmental flows are needed to provide feedback to managers as to whether desired fisheries-related outcomes are being achieved under current water allocations.

Enhancing the research outcomes - integrating across research disciplines

An integrated research program is needed to develop a robust sampling proceedures that can investigate the role of freshwater flows in estuaries and the impacts of modified flows on fisheries production. The CZCRC offers the opportunity to integrate flow-influenced fisheries data with other hydrological (i.e. costal modelling) and primary productivity (i.e. nutrient cycling) research projects that will provide greater insight into ecosystems processes.

*Public perceptions
Commercial fisheries, in particular prawn fisheries, conjour negative perceptions of environmental impact by the general community. This stems as much from the negative imagery of capture of species of intrinsic public e.g. dolphins, as it does from notions that commercial fisheries irreversibly deplete stocks.

*Adverse consumer response
Public perceptions have been shown to translate into adverse consumer response. In addition, domestic perception and political pressure threatens the actual conduct of fisheries rather than the market for the product. There is a clear need to better inform the Australian public on the environmental performance of commercial fisheries by identifying environmental impacts and promoting responsible work practices.

*Improved promotion of commercial fishing
The proposal addresses a major need for more effective promotion of commercial fisheries linked to domestic perceptions and market opportunities.

*The ecosytem effects of fishing need to be understood.
Most of Australia's major fisheries are undertaken in nearshore habitats yet relatively little is known of the effects of fishing on coastal ecosystems. This project seeks to address this question for a major coastal fishery. The objectives of the project are consistent with the aims of modern fisheries management and have been identified as an information need by FRDC.