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a b s t r a c tThe Southern and Eastern Scalefish and Shark Fishery (SESSF) is a complex multi-species fishery, with 34 stock units under quota management, for which a harvest strategy framework was developed in 2005. The framework involves the application of a set of tier-based harvest control rules (HCR) designed to provide a precautionary approach to management. The harvest strategy framework has been applied from 2005 to 2007, resulting in substantial reductions in quotas across the fishery. The experience in implementing the framework, both positive and negative, is described, and general lessons are drawn. Key lessons include the importance of formally testing such strategies using management strategy evaluation, the impact of external management drivers on implementation of the approach, the need to define strategies for setting "bycatch quotas" in multi-species fisheries, and the need for flexibility and pragmatism in the early stages of implementing such an approach.

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Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. We identified that 59% of the metadata collected are not publicly available, highlighting that the availability of data is the most important challenge to assess species redistributions under global climate change. Given that the primary purpose of surveys is to provide independent data to inform stock assessment of commercially important populations, we further highlight that single surveys do not cover the full range of the main commercial demersal fish species. An average of 18 surveys is needed to cover at least 50% of species ranges, demonstrating the importance of combining multiple surveys to evaluate species range shifts. We assess the potential for combining surveys to track transboundary species redistributions and show that differences in sampling schemes and inconsistency in sampling can be overcome with spatio‐temporal modeling to follow species density redistributions. In light of our global assessment, we establish a framework for improving the management and conservation of transboundary and migrating marine demersal species. We provide directions to improve data availability and encourage countries to share survey data, to assess species vulnerabilities, and to support management adaptation in a time of climate‐driven ocean changes.

There is an increasing expectation for decision makers to use robust scientific advice on the status of exploited fish stocks. For example, Australia has recently implemented a harvest strategy policy for federally managed fisheries based on limit and target biomass reference points. In common with most fisheries jurisdictions, however, Australia has many data‐poor species and fisheries for which biomass estimates are unavailable. Consequently, the challenge for those tasked with providing management advice for Australian fisheries has been reconciling the need to achieve specific risk‐related sustainability objectives with the reality of the available data and assessments for data‐poor species and fisheries. Some general recommendations regarding how to achieve this balance are drawn using case studies from two multispecies trawl fisheries. The lack of data on which to base quantitative stock assessments using population dynamics models does not preclude the development of objective harvest control rules. Evaluation of harvest control rules using technical procedures (e.g., the management strategy evaluation approach) is ideal, but implementation before rigorous testing is sometimes a necessary reality. Information from data‐rich species and fisheries can be used to inform “assessments” for data‐poor species and thereby develop appropriate control rules. This can be done through formal methods, such as the “Robin Hood” approach (in which assessments from data‐rich species are used to inform assessments of data‐poor species), or less formally by grouping species into “baskets” and basing management decisions on one appropriate member of the group. Stakeholder knowledge and buy‐in to the process of developing appropriate harvest strategies are essential when species or fisheries are data poor. Use of this information, however, needs to be constrained by policy decisions, such as prespecified performance standards. There will always be a trade‐off between the cost of data collection and the value of a fishery; in this article, we highlight that this trade‐off does not have to be a major impediment to the development of realistic and sufficiently precautionary control rules for the management of data‐poor species and fisheries.