Proposal for continuation of Australia’s research plan for exploratory fishing for toothfish (Dissostichus spp.) in East Antarctica (Divisions 58.4.1 and 58.4.2)

Exploratory fishing for toothfish (Dissostichus spp.) in East Antarctica (Divisions 58.4.1 and 58.4.2) began in 2003. Robust stock assessment and catch limits according to CCAMLR decision rules remain to be determined for these Divisions. The 2015/16 season was the first of a three-year research plan which was developed by Australia (WG-FSA-15/47 Rev. 1) under Conservation Measure 41–01. Australia will present to WG-SAM-2016 a full report on the fishing operation, catch composition, tagging and biological sampling undertaken by Australia during 2015/16 in SSRUs 58.4.1E and 58.4.1G. Here, we evaluate the original research plan set out in WG-FSA-15/47 Rev. 1, and propose continuation of this research in the 2016/17 season. Ongoing standardised longline fishing, in conjunction with fish biological measurements, tagging and aging, will be used to develop a stock assessment/s for Divisions 58.4.1 and 58.4.2, and inform the necessary considerations of spatial structure, biomass and connectivity of toothfish populations. In addition, environmental data from CTD (conductivity, temperature and depth) and video loggers will contribute to models of toothfish habitat use. These models will inform spatial management approaches for toothfish, and the conservation of representative areas of benthic biodiversity. Additional outcomes include mapping of the bathymetry of fishable areas, and improved understanding of the distribution, relative abundance, and life histories of bycatch species.