Over 300 species are caught in the SEF, of which around 100 have commercial value. Twenty five species comprise around 90% of the landed catch. Each year, however, quotas are set for only around 17 species. There are 10 of these species for which there is (or has been) some formal stock assessment (that may not occur every year). For all of the remaining quota species and some of the more important non-quota species, no formal assessment is undertaken and the only assessment that can be made is based on investigation of trends in catch and effort and size distribution and anecdotal input from scientists and industry. There is simply not enough resources to undertake formal stock assessments for the wide range of commercial species landed in the SEF. Yet, each of these species is an important component of the catch of fishers. If the fishery is to continue to operate in its current form and meet the strategic assessments required under the EPBC Act, some form of formal assessment is required.

A recently completed ARF project (Production parameters from the fisheries literature for SEF-like species - Project no R99/0308) demonstrated the utility of using information for "similar" species when conducting assessments for SEF species. Using key parameters such as the virgin biomass, the rate of natural mortality, and the “steepness” of the stock-relationship relationship, a simple formula was developed for identifying “similar” stocks / species and an algorithm was developed for constructing prior probability distributions for these parameters. The resultant distributions can be used in Bayesian stock assessments and as the basis for sensitivity tests when applying other methods of stock assessments. The current project will refine the prior distributions for the production parameters and develop and test methods of stock assessment that use the results of assessments for well-studied species in a formal manner to inform assessments of ‘data-poor’ species. If successful, the methods developed would lead to significant benefits not only for the assessment and management of "data poor" SEF low priority, by-product and by-catch species, but also for a range of new and developing fisheries in Australia.

Blue-eye trevalla is an important species in the South East Fishery. Blue-eye trevalla is taken in large quantities by the trawl and non-trawl sectors in south eastern coastal waters and around offshore seamounts. Despite the high value of this species in the trawl and non-trawl fisheries, however, there is limited information on the stock structure and appropriate management units. Bolch et al. (1993) concluded there was sufficient gene flow to prevent genetic differentiation between blue-eye trevalla off Tasmania, South Australia and NSW, but the sample sizes were small, there are limitations to allozyme electrophoresis (the method they used), and they did not sample fish from NZ. Ward and Last (1993) suggested that, given the known limitations of allozyme electrophoresis, further genetic studies based on mitochondrial DNA analyses and larger samples be undertaken. As a consequence, the relationship between fish caught off the south eastern Australian coast and those taken from offshore seamounts is unknown. The need to identify the stock structure of Blue-eye trevalla has also been identified as a high priority by the blue-eye working group and SEFAG.

In recent years, developmental trawl fishing has been occurring in the East Coast Deep Water (ECDW) fishery. Significant amounts of blue-eye trevalla have been caught in this fishery from grounds well to the east of 157ºE, and currently these fish are under the same quota restrictions that apply to the rest of the SEF trawl fishery. The large distances between the ECDW fishing grounds and grounds where most of the east coast blue-eye are caught has led fishers to question whether the ECDW fish can be considered part of the stock upon which the TAC was based. There is an urgent need to assess the stock structure of blue-eye trevalla caught throughout the SEF, the ECDW fisheries and New Zealand. The results from a study assessing the stock structure of this species will provide managers with information on potential management units.

A proposal to investigate the relationships between blue-eye trevalla caught in the ECDW zone and the SEF was submitted to AFMA in 2001, and although supported, it was not funded at this time for a number of reasons. In response to suggestions from AFMA, the MACs and SEFAG, it was decided that the proposal should be re-submitted in 2002. To address suggestions from industry and management groups that the stock structure of blue-eye needed to be evaluated over a much larger area, the extent of the project was expanded to include blue-eye samples from across south eastern Australia, including offshore seamounts (such as those off Tasmania, Norfolk and Lord Howe Islands) and New Zealand.