CCAMLR

Suggestion and comments on changes in basic documents for scientific observers (logbook, cruise report etc.) produced during the inter-session SISO work are presented in the paper. Position of the Russian Federation on development of centralized preparation and accreditation scheme for scientific observers and CCAMLR member countries is amplified here.

Available data on the by-catch of Rajiformes was extracted from the CCAMLR database. These records included commercial catch data as well as observer data. Spatial distribution and biological data was broadly consistent with current literature although there were indications of larger spatial ranges for some species.  The data collected as part of CCAMLR fisheries represents a very substantial repository of information on Southern Ocean Rajiformes; realising the full potential of this data will require a review of the consistency and accuracy of identification of taxa and this might be a useful for a future focus topic in the SISO.

In 2013, POKER Biomass survey was undertaken at Kerguelen Islands (Division 58.5.1) to collect information of all the fish species including the mackerel icefish, Champsocephalus gunnari. Data from this random stratified trawl survey, added to the previous results of 2006 and 2010, 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 840 t is recommended for 2014 and 580 t for 2015.
 

Depredation is a human-wildlife conflict over resource which often includes a combination of socio-economical, ecological and conservation issues. However, estimating the amount of depredated resource can be especially challenging when depredation occurs on fish in the marine environment. This is the case for killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus) depredation on the demersal Patagonian toothfish (Dissostichus eleginoides) longline fishery operating within the Crozet Islands EEZ (southern Indian Ocean). As the two species remove the entire fish from the hooks whether they depredate longline hooks separately or simultaneously, this study aimed at providing two indirect methods of assessment of depredated biomass over a 11-year period (from 2003 to 2013), both accounting for spatial variations of depredation levels. In the first method, we used fishing data from 6 525 longline sets to calculate the difference between Catch Per Unit Effort (CPUE) of non-depredated and depredated hooks. From this difference and using the fishing effort (number of hooks), we estimated that 575 ± 35 t and 739 ± 87 t of Patagonian toothfish were respectively depredated by killer whales and sperm whales when the two species occurred separately, and 1 679 ± 74 t were depredated from 2003 to 2013 when the two species co-occurred around vessels. The second method was new in a way that we used the differences of proportion of by-catch species (i.e. grenadiers – Macrourus sp.) between non-depredated and depredated longline sets to estimate the number of depredated Patagonian toothfish. This approach, which can only be implemented when a sufficient level of bycatch species occurs,  provides strong support to the CPUE method. From these two methods, depredation rates were estimated to range from 27,3% to 29.1% % of the total capture (landed + depredated), that is one of the highest among all similar depredation situations reported elsewhere in the world. In addition to providing methodology insights that could be used in other areas with such depredation issues, these findings emphasize the critical importance for fishery managers and researcher to account for depredation when assessing fish stocks, fishery economy and/or conservation of odontocetes.

Closed mostly within the Weddell Sea Subarea 48.5 is one of the closed data-poor CCAMLR subareas, where stock assessment should be carried out. In spite of hard ice conditions at most part of the Weddell Sea during most time of the year, this large water area is very similar with the Ross Sea. This similarity, which could be found in geographical location, bathymetric profile, currents system and follows from results of the first and the second stage of this program, highlight the Weddell Sea as one of the most promising area for exploratory fishery of Dissostichus sp. However, fishery in Subarea 48.5 is closed on the basis data on stock assessment absence. The main objective of the present program is collecting data for reliable stock assessment and following estimation of precautionary limits in accordance with CCAMLR decision rules. The program contains schedule and research program of the third stage of the Russian Federation multi-year research program in the Weddell Sea that are prospected for 5 years. Detailed plan of fishing operations, collecting and analysis of data will be provided for the Scientific Committee and Commission consideration.

In 2011/2012, the Saint André conducted its first exploratory fishery for Dissostichus spp. in division 58.4.3a. France notified its wish to continue this exploratory fishery over the coming years in order to achieve a robust stock assessment that would provide advice on a catch limit according to CCAMLR decision rules. This paper aims to present a research plan for 2014/2015 that takes into account the remarks made during the WG-SAM 2014. The objective is to progress on modelling tools and to improve the estimation of current biomass. The stock size in division 58.4.3a was estimated during WG-FSA 2013 using the Petersen estimator, CASAL model and the CPUE x seabed analogy method. The estimates of biomass are highly biased, because catch data used in the calculation derived from a small location at which catch rates were high, but these are extrapolated over the entire area, including to areas in which catch rates are known to be much lower. Given these results and the concentration of fishing effort, it is suggested to define a new survey design and to maintain the total catch limit of 32 tons agreed in 2012 in order to result in sufficient tag recaptures and to substantially refine the stock assessment next year. It is suggested also to define a catch limit with an appropriate local exploitation rate (4%) equivalent to 4 tons inside a research block where catches were high.

Regarding the low levels of stocks of Dissostichus spp. and the high levels of IUU fishing, CCAMLR decided to close the fishery in 2002 in division 58.4.4. Since 2008 only one vessel, Shinsei maru No. 3, has conducted research fishing in accordance with a research plan submitted under CM 24-01. France notifies its wish to collaborate in this research fishery over the coming years in order to participate in the tagging program and achieve a robust stock assessment. The aim is to provide advice on a catch limit according to CCAMLR decision rules and allow an earlier decision to reopen this area. This paper presents a research plan for 2014/2015. The stock assessments are still in development and the estimates of abundance are not sufficiently reliable to define a new catch limit. France suggests continuing with the same survey design and with the total research catch limits agreed in 2013: 25 tons for SSRU C and for 35 tons for SSRU D. It is likely to result in sufficient tag recaptures to substantially refine the stock assessment.