The purpose of this species identification illustrated guide is to facilitate by-catch species identification with real photographs in the Southern ocean. All of the photographs provided in this guide have been taken photographs by the author from aboard trawler (Target species : Euphausia superba) and longliner (Target species : Dissostichus spp.) of commercial fishery purposes in the Southern ocean. The author welcome notification of any errors or possible improvement to this publication. Welcome cooperation with interesting contributor and research body for development this guide.

The research fishing had conducted in Divisions 58.4.1 and 58.4.2 from 12 November 2014 to 24 March 2015. Total 9 species including D. mawsoni had occurred, and D. mawsoni were caught 4,016 individuals with 131,992 kg. The research fishing using tags were conducted according to the CCAMLR CM, and 706 individuals were tagged and released for tagging recovery. And both of tagging rate and tag overlap rate were over 5, and reached about 80%, respectively. To get biological information, it was examined length, weight, sex and gut contents of each individual. In addition, studies related on marine environment were conducted for sampling fishes and plankton, getting information through CTD (Micro CAT, SBE37SMP) and satellite archival tags (Mini-PAT). These surveys, however, had not been conducted continuously due to weather condition and freezing floating ice. While conducting surveys, one of nets for sampling plankton was lost, and CTD equipment was damaged. It is judged to need measures for supplementing equipment handling for continuous research fishing.

For the 2014 assessment of Patagonian toothfish (Dissostichus eleginoides) around the Heard Island and McDonald Islands (HIMI) in Division 58.5.2, a prior for catchability q of the random stratified trawl survey (RSTS) was estimated by comparing abundance estimates of the survey with abundance estimates calculated from the tag-recaptures data on the main trawl ground. Here, we use simulations to address potential bias in the estimation of q and conclude that the potential bias that may arise from fishing selectivity cannot be corrected for given the available data.  

In the absence of an unbiased estimate of survey catchability, we recommend that a non-informative prior with uniform distribution be used for abundance estimates from trawl surveys in a toothfish stock assessment. The bounds of such as uniform prior should be wide, e.g. 0.1-1.5, since many processes act on catchability at the same time which collectively result in an estimate of catchability that can be well below or above 1.

Toothfish in SSRUs 882.A–B are currently managed as part of the Ross Sea region stock, but the stock structure and fish movement patterns are uncertain and more information is required for the management across all of the region. Recognising this requirement, the Scientific Committee endorsed two years of spatially stratified longline surveys in the northern region of SSRUs 88.2A–B (SC-CAMLR XXXII, paragraph 3.76 (iv-c)). A multi-year, multi-Member research program was therefore established to map and sample the fishable areas of SSRUs 88.2 A–B north of 66° S latitude. Following its successful completion of the first part of the two year survey, this paper presents the details of the vessel that will conduct the second year of research during the 2015/16 season and summarises the research plan, previously agreed at CCAMLR XXXIII.

A multi-year, multi-Member research program was established to map and sample the fishable areas of SSRUs 88.2 A–B north of 66° S latitude. During the 6^th - 10^th February 2015, the UK fishing vessel Argos Froyanes surveyed SSRU 88.2 A research block 4 defined in the multi-Member 88.2 offshore research survey. Bathymetric data was collected and longline fishing conducted to release tagged fish and collect information on the characteristics of the toothfish inhabiting the region. The vessel set 7 longline sets with all vessel operations conforming to the required research criteria. A catch of 49 tonnes of D mawsoni and small catch of 29 kg of two D eleginoides was taken; 150 tagged fish were released at 3.1 fish tagged per tonne and a tag overlap statistic of 85%.

A link between D. eleginoides stocks in Subareas 48.3 and 48.4 has been speculated for some time. Different growth rates and maturity suggest that there is no regular exchange between the two areas, but tag recapture data clearly show a small number of toothfish moving between them, while genetic analysis also indicates that both stocks belong mostly to the same genetic population. Here we examine the information currently available. 

Characterisation of fishery selection is key to reducing uncertainty in the assessment and management advice provided for CCAMLR toothfish stocks. Toothfish migrate towards deeper waters as they age and increase in size and, in combination with the practical difficulties associated with deploying fishing gear at increasing depths, there is the potential for a dome shaped selection with age and size to arise. However this type of selection pattern is associated with the estimation of highly uncertain quantities of cryptic biomass. A review of the fishery and tagging data from the Patagonian toothfish (D. eleginoides) in Subarea 48.3 is used to determine whether there is sufficient information to determine the most likely fishery selection profile. A simple metric, the distribution of tag age with depth, is suggested as an indicator that a dome selection pattern is unlikely in the 48.3 fishery.