CCAMLR

This paper briefly outlines the key scientific issues that should be resolved for providing sufficient information with the aim of quantitative understanding regularities and trends of krill spatial distribution in the Scotia Sea being the important information for developing management strategy for krill stock in the Area 48. Proposals concerning scientific activity needed for resolving issues are shown. Practical implementation of these proposals will contribute to attaining CCAMLR goals in krill stocks management.  
 

The fish sampling protocol (K12 form) was developed to ensure that small/larval fish, that  may go undetected in larger samples, are recorded using a sorting method with a standard sub-sampling approach that allows the user to re-sort smaller samples and maximises potential to detect by-catch.
This paper uses data collected using the fish sampling protocol (K12) during 2010 and 2011 in order to estimate finfish by-catch in the krill fishery.

The information regarding by-catch of finfish in the krill fishery is limited and 2010 was the first year when the simplified sub-sampling method was used.  With more data from the upcoming season and greater observer coverage across the fishing fleet, better by-catch estimates should be able to be generated.
 

Summary of fishery-related information for WG-FSA including availability of data, catches of target and by-catch species in assessed and exploratory fisheries, tagging rates and the tag overlap statistic, notifications (fisheries, research and VMEs), development of species profiles and findings of the review of CCAMLR’s data management systems. Where applicable, the 2011 draft fishery reports and report on bottom fisheries and VMEs for WG-FSA have been updated with this information prior to the meeting.

Software is presented for the automated production of standardised image plots of spatially referenced bottom fishing impact assessments. This software is submitted to WG-FSA to assist the Secretariat or CCAMLR Working Groups in the production of integrated bottom fishing impact assessments, including routine update of the circumpolar impact assessment originally described in SC-CAMLR-XXIX/4, Appendix E.

The background to the current CCAMLR toothfish tagging programme is reviewed and recent performance measures implemented by CCAMLR to control and monitor the tagging of toothfish (Dissostichus species) in exploratory fisheries carried out within the Convention Area are described.  Following the first season of implementation we describe several circumstances which will cause anomalies in the tag overlap statistic used to monitor tagging performance.  These relate to differences in the length distribution of Dissostichus species within the assessed management division (ASD) or changes in the tagging rate within sub areas of the assessed ASD.  The current level of two tonnes of Dissostichus catch triggering the requirement to achieve a tag overlap statistic of 60% or more for upcoming season as specified in Annex 41-01/C is evaluated by means of simple simulations.  The results of this analysis indicate that at low levels of tagging, equating to between 2 and 10 t of Dissostichus catch, there is a strong likelihood that a breach of the Measure would occur.  We make recommendations from a user perspective on other aspects of toothfish tagging such as crew participation in the process, tag colour, training, and clarification of the controlling measures. We also recommend that the CCAMLR tagging protocol be updated and translated.
 

New Zealand will deploy four pop-off satellite transmitters on Antarctic toothfish along the Ross Sea continental slope in January 2012. They will be programmed to pop-off the fish, float to the surface, and transmit in December 2012. The purpose of this paper is to provide an announcement for members to distribute to vessels, crew and observers given the chance that these fish may be encountered in the fishery. The announcement details what to do if a satellite tagged fish is encountered, and who should be contacted. A second page provides specific instructions to observers and vessel crew that could be translated and provided directly to industry via the CCAMLR website.

Stock assessments rely upon estimates of the total mortality resulting from fishing activities. The level of mortality resulting from the loss of sections of bottom longline gear in the Ross Sea region and Subarea 88.2 Antarctic toothfish (Dissostichus mawsoni) fisheries is not currently known. Lost fishing gear should be monitored to provide information to evaluate how well CCAMLR meets its management objectives relating to human impacts on the Antarctic environment. We provide a method to estimate unaccounted fishing mortality from lost lines in the Ross Sea region and Subarea 88.2 Antarctic toothfish fisheries. Our estimates suggest that on average 175–244 t of Antarctic toothfish may be unaccounted annually. While these estimates may be improved through better data reporting practices, the current estimates have been provided as sensitivities in the 2011 stock assessments for the Ross Sea region and Subarea 88.2 fisheries.
 

Descriptive analyses of the toothfish tagging programme in Subareas 88.1 and 88.2 are updated, including summaries of data for the 2011 season. Overall, a total of 28 458 Antarctic toothfish have been reported as released and 1417 recaptured, and 1124 Patagonian toothfish released and 67 recaptured since 2001. In recent years, most vessels have achieved or exceeded the target tagging rate of one toothfish per tonne of catch in the Ross Sea region.

Tag recapture data showed that most fish are recorded as being recaptured only a short distance from their point of release, typically less than 100 km. However, several long distance movements of tagged Antarctic toothfish between the north and slope regions have been observed. Long distance movements to the north were recorded for six fish that moved from SSRU 88.1H to 88.1C; two moved from SSRU 88.1H to 88.1B; and one from SSRU 88.1I to SSRU 88.1C. Long distance southwards movements were recorded for three fish that moved from SSRU 88.1B to SSRUs 88.1H; and one to SSRU 88.1I. In addition, several fish moved long distances on the slope and the shelf, with movements between SSRUs 88.1H, 88.1I, and 88.1K to grounds off Terra Nova Bay and Ross Island in SSRU 88.1J and vice versa..

The total number of recaptures in 2010 and 2011 was at a similar level to 2007 and 2008 and about double that in 2009. The reason for the low number of recaptures in 2009 is unclear but is more likely to be related to the different locations of fishing in 2009 rather than a lower detection rate.
 

The exploratory fishery for Dissostichus spp. has now been operating for fifteen years in Subarea 88.1 and for ten years in Subarea 88.2. This report summarises the timing, depth, and location of fishing together with the catch of Dissostichus spp. and bycatch species by year for the period 1997–98 to 2010–11. During the 2010–11 fishing year most of the catch in Subarea 88.1 came from the slope SSRUs 88.1H and 88.1I, and SSRU 88.1K. About 63% of the catch limit in the north was taken from 88.1C with the rest taken from SSRU 88.1B. The catch limit from the shelf was taken mainly from 881J. Most catch from Subarea 88.2 was taken from SSRU 88.2E but over 100 t was taken from each of SSRU 88.2D and 88.2F, and SSRU 88.2C was fished for the first time.

Unstandardised raw catch and effort data examined during this study suggest that the median toothfish catch per set has generally increased over the course of the fishery whilst the median number of hooks per set has remained relatively constant. Other indicators of CPUE including unstandardised catch per set and catch per hook have varied considerably over time in each of the fisheries showing no trend. There is no evidence of any truncation of the overall length frequency distribution, but some evidence for a reduction in median fish length in SSRUs 88.1H and 88.1I over the last 1–2 years as a mode of smaller (c. 100 cm) fish is selected by teh fishery, most likely  related to fishing depth. We conclude that from data examined from the fishery to date there is no evidence for substantial changes in population structure or abundance at the regional (Subarea) or local (SSRU) level.