• Reliability of rod catch data. A number of respondents expressed concern over the potential shortcomings of using rod catch data to estimate run size. The main concerns were that these data do not account for components of the stock that may enter and ascend rivers outside the fishing seasons, and that salmon may be mistaken for sea trout.

It is important to note first of all, that in the absence of traps or counters on a river, rod catch figures provide the best available data for estimating stock abundance, and we are therefore reliant on accurate reporting by anglers. However, current procedures used to derive run size from rod catch are based on estimates of exploitation, which do take into account the out of season run.

The provisional nature of the Conservation Limits (CLs) should be noted. Although CLs have been used in salmon management in North America for many years, they are a relatively recent development in England and Wales.

Egg deposition estimates are likely to be affected by a number of factors. In particular, in recent years, there is likely to have been an overall decrease in effort for salmon, in response to legislative changes. Current procedures for setting CLs (as well as for estimating egg deposition) may also fail to take adequate account of the fact that many rivers, in particular some of the smaller catchments on the West coast of Wales, support relatively small salmon stocks and are principally regarded as sea trout rivers. A number of rivers are also in the process of recovering from previous pollution and may therefore require interim rebuilding targets to be set (CEFAS & Environement Agency, 2001).

The Agency is working to improve methods to derive and apply conservation limits and related ‘targets’ to salmon fishery management – a process which is likely to result in refinement of methods used in this SAP in the future.

An improved procedure for estimating angling exploitation is currently being developed. This will take account of annual changes in fishing effort, as well as partitioning effort between salmon and sea trout. The new procedure will be available in 2002 and should be able to be applied retrospectively to previous data sets.

Data from the acoustic fish counters installed on the Teifi and Tywi are also currently being used to aid understanding of salmon runs and exploitation rates in SW Wales. The Agency also intends to review the need for a counter on the Ogmore and look for opportunities for funding.