Effective fishery management requires knowledge of the impact of fishing on stocks - good monitoring measures of harvest rates (U). However, there are NO reliable indices of U or of abundance for many fished species. Most methods are flawed; some (eg CPUE) may only indicate the impact of fishing when populations are depleted. Lack of effective monitoring means loss of catch, income and recreation and jeopardizes sustainability. Although an obvious method of measuring U, conventional tagging is strongly limited by post-release mortality, tag shedding and non-reporting of tags. We propose that genetic “tagging” - individuals identified from tissue collected with special lures or spears, and subsequent screening of the commercial catch to establish a “recapture rate” – largely overcomes the problems of conventional tags. We need this monitoring method. Even a modest increase in monitoring information quality translates to real economic and sustainability benefits. Anglers provide useful information on movements and growth (eg through SUNTAG tagging). But the information they provide for monitoring U is limited by the general tagging problems. By coupling conventional with genetic tagging, this project provides a direction for improvement of recreational tagging, by calibrating and quantifying problems, and developing them as a source of auxiliary information. This could substantially increase the value of recreational tagging.

There is currently NO effective monitoring method for Spanish mackerel: they are not amenable to survey, and because they school, CPUE is a poor abundance measure. They have poor post-tagging survival, with low return rates (<5% ; Sawynock, pers. comm.). Lack of good monitoring information is of concern for all Australian mackerel fisheries; in several there are real concerns about harvest rates. It was concluded in stock assessment workshops conducted in Darwin in August 2000, led by Prof. Carl Walters and Dr Norm Hall, that the primary research direction for mackerel and several other fisheries should be the development of new tagging approaches. The method we propose meets that direction and could provide effective monitoring for a wide range of fisheries in which current status is otherwise very uncertain.