Results of the 2015 multi-Member longline survey for toothfish in the northern Ross Sea region (Subarea 88.2 SSRUs A–B) and proposal for 2016 operations

The first year of a two-year and multi-member research survey using standardised longline gear to sample toothfish populations was carried out in the northern areas (60°‑ 66° S) of SSRUs 88.2A–B. The sampling strategy and data collection adhered to standards set in CM 41-10 (2014). A total of 109.1 t of Antarctic toothfish and two Patagonian toothfish (0.029 t) were caught. Toothfish catch rates, size, sex ratio, and reproductive maturity status were similar to existing data from SSRU 88.1C. Age composition of the catch as predicted by the spatial population model was similar to that observed in the survey. The gonadosomatic index showed a decreasing trend from west to east across the research blocks. The percentage of fish with empty stomachs was high, but prey diversity and quantities of prey items were similar to those reported from the northern Ross Sea. Bathymetry data were collected during the survey and during transit across research blocks and have been provided to the CCAMLR Secretariat. We recommend continuing the survey with minor modifications to aid in the achievement of the objectives including specification of data collection requirements, bathymetric survey requirements, research block-specific catch limits to ensure a greater spread of effort, and a higher level of scientific oversight of survey operations to ensure optimal scientific design and data collection.