Abstract: Catch in the groundfish hook and line fishery on Canada’s west coast has been monitored since 2006 by an interrelated suite of components. In addition to 100% EM coverage, these include full independent dockside monitoring, fisher logbooks and complete retention of rockfishes. Each component, in spite of its weaknesses as a stand-alone monitoring tool, makes an essential contribution without which the overall program would fail to meet the minimum objectives. Over the ensuing eight years, the program has surpassed expectations in meeting conservation and operational information goals by providing adequate and timely estimates of total catch for all quota and many non-quota species. This presentation will first focus on the impact that the improved data has had on management and stock assessment. Among other issues, it will include examples of how the information on discards was for historical reconstructions of discards as well as how managers and industry are taking advantage of the certainty in the discards estimates to implement fine-scale management devices to address the estimation of rare catch events and impose extremely small vessel discard caps. The presentation will also focus on issues of data quality and completeness, some of which remain unsolved.