CCAMLR

Three species of skate, Bathyraja eatonii, B. irrasa and B. murrayi, are commonly taken as incidental by-catch in Patagonian toothfish (Dissostichus eleginoides) longline and trawl fisheries, and the mackerel icefish (Champsocephalus gunnari) trawl fishery on the Kerguelen Plateau (KP) in the southern Indian Ocean. Data from fishery observations for 1997 to 2014 shows that the three skates were widely distributed across the Kerguelen Plateau, showing different spatial distributions, linked mainly with depth. Off Heard Island and McDonald Islands (HIMI), in the southern part of the KP, B. eatonii and B. irrasa were most abundant to the north and northwest of Heard Island, out to the edge of the Australian Exclusive Economic Zone, and were caught down to depths of 1790 m and 2059 m respectively.  The smallest species, B. murrayi, occurred mainly in the shallower waters down to 550 m, and was most abundant to the north and northeast, close to Heard Island. Around Kerguelen Islands, in the northern part of the KP, skates were most abundant between the 500m and 1000m contours circling and extending from the islands.

Catch rates were modelled using zero-inflated GAMs and GLMs. The catch rates of skates from the trawl fisheries in the Australian EEZ surrounding Heard Island and McDonald Islands have shown little evidence of depletion on the main trawl fishing grounds, although there is evidence of a decrease in the average total length of B. eatonii.  The marine reserves and the conservation measures employed by the Commission on the Conservation of Antarctic Marine Living Resources in the HIMI fisheries, appear to provide effective protection for the skates, at least in the shallower waters where the trawl fisheries operate. B. irrasa taken in the deeper waters where longline fishing occurs have shown a slight decline in catch rate over the years of the HIMI fishery. Although all skates are returned to the water from this fishery, survival rates are unknown and careful monitoring should continue to assess the status of these stocks. There appears to be little change in the abundance of the skate species at Kerguelen in the time period.

This study provides the first review of skate by-catch across both the HIMI and Kerguelen fisheries. Ongoing monitoring of species specific by-catch levels and further research to determine the important life history parameters of these species are required, particularly for B. irrasa which is taken in both trawl and longline fisheries.

CCAMLR XXXIV endorsed a trial pre-season extension (1-14 April) and a new conditional trial post-season extension (15-30 November), in addition to the existing pre-season (15-30 Apr) and trial post-season extension (1-14 Nov) in the Patagonian toothfish longline fishery in statistical division 58.5.2 (WG-FSA-15/48). Australia undertook to report annually on the results of both trials. This paper presents information on fishing effort and seabird interactions with fishing gear collected during the periods 1-14 November 2015, 1-14 April 2016 and 15-30 April 2016.

This paper presents the latest developments in Casal models for Crozet with an updating of input data from the more recent years (up to 2015/16 season) and a reassessment of stocks taking into account the previous remarks of the WG-FSA meetings.

In 2015, An Icefish specific trawl survey was undertaken at Kerguelen Islands (Division 58.5.1) to collect information about the size distribution and the biomass status of mackerel icefish, Champsocephalus gunnari. Data from this random stratified trawl survey was used for a short term assessment of C. gunnari on Kerguelen EEZ. The standard CCAMLR methods were used to provide potential yields, a catch limit of 8278 t is recommended for 2016 and 6701 t for 2017.