In NSW, inherent variation among the characteristics of different estuarine fisheries has resulted in a range of physical modifications designed to improve the selectivity of conventional gears. While some of these designs have been effective in reducing the bycatches of unwanted species by up to 95%, rates of reduction more commonly range between 30 and 70%. Such reductions have obvious benefits for the stocks of bycatch species. considering the magnitudes of bycatches in many estuarine fisheries, and especially those targeting prawns (i.e. often 1000s of fish per haul), it is apparent that despite the use of modified gears, in nearly all cases there still remains some capture and mortality of unwanted individuals.

To augment the post-release survival of unwanted bycatch throughout nearly all of NSW estuarine fisheries (including those involving static gears, where no BRDs have been developed), ancillary options within the second category of input controls (listed above in B2) need to be investigated. The sorts of modifications that warrant examination include, defined soak times for gears, devices to limit predation on discarded bycatch, netting materials in codends that reduce damage to bycatch, the use of gloves to handle bycatch, and the utility of separating target and bycaught species in water after capture.

The majority of these operational and/or post-capture handling procedures have NOT been examined, but have the potential to significantly reduce the remaining impacts of commercial fishing gears on non-target species and sizes in NSW’s estuaries. This is one of the main research priorities detailed in the Fishery Management Strategy for the NSW Estuary General Fishery and comprises a key category within the 2004-2007 Strategic Research Plan for Fisheries, Aquaculture and Aquatic Conservation in NSW. Quantification of the utility of this category of input controls would also have benefit and application throughout all other coastal fisheries in Australia.

The research will form the basis of a PhD candidature. This approach is justified because (i) the work is new and there is sufficient intellectual content to support a PhD student, (ii) there is a paucity of researchers with higher degrees working in the applied fields of gear technology and bycatch mitigation in Australia and (iii) previous, similarly-structured FRDC projects (e.g. 93/180 and 2001/031) have resulted in successful PhD candidatures by project staff. Specifying a PhD candidature formalizes what would already occur if funding was sought for a Fisheries Technician, but at approx. 1/3 the cost, while attracting a substantial in-kind contribution from affiliated institutions (the National Marine Science Centre and University of New England).

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.

*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.