This report summarises the timing, depth, and location of fishing together with the biological aspects and catch of Antarctic toothfish for the period 1997–98 to 2012–13. In 2012–13, all the Ross Sea slope SSRUs were clear of ice and catches were evenly distributed across the three SSRUs. As in recent years, the remaining catches came mainly from SSRUs 88.1C, 88.1J, and 88.2H. Unstandardised Antarctic toothfish CPUE in the Ross Sea and Subarea 88.2 fisheries have fluctuated over the past 10 years with no trend. A standardised CPUE analysis in the Ross Sea fishery showed an increase to 2008 followed by a slight decline to 2013. Standardised CPUE indices in Subarea 88.2 showed a general decline from 2003 to 2013 in SSRU 882H, but a general increase from 2006 to 2013 in SSRUs 88.2C–G. However, these indices were very uncertain due primarily to the lack of a consistent set of vessels over time and may not be indexing abundance.
Length frequency distributions of Antarctic toothfish in the Ross Sea fishery have continued to be reasonably stable in the North and to have a strong mode of smaller fish on the Slope. Mean ages and ages of larger fish increased in the first few years of the fishery in each area but have declined since 2005. The trend on the Slope appears to be confounded by the trend of some vessels fishing shallower there in the last four years. There is some evidence for a similar reduction in mean age in SSRU 88.2H, but the data are very uncertain due to the paucity of otolith readings and it is recommended that the age data are given low weighting in the 2013 assessment and that otolith readings for this area are given a high priority. There has been a marked change in sex ratio in the North of the Ross Sea fishery, with an increase in the proportion of males since 2001, but with little change in the rest of Subarea 88.1 or 88.2.