CCAMLR

To facilitate access to spatial data for use in analyses and generating graphics (i.e. maps) in R the CCAMLRGIS R package has been upgraded to provide direct access to polygon data that can be viewed on the online GIS. This package can also be used to create polygon data that can either be used directly in R or be output as shapefiles that can be loaded into other programs and/or back onto the online GIS.  In this paper we provide information on the data format requirements for generating polygon data and explain how polygon data on the online GIS can be loaded into R. 

This study used an operating model to simulate a Dissostichus eleginoides population in Research Block 5843a_1 with a fixed exploitation rate and various tagging rate scenarios to assess the impact on the numbers of tagged fish recaptures and accuracy of tag-based estimates using the Chapman estimator. The results showed that tag-based biomass estimates obtained from a low numbers of recaptures will have a high risk of over-estimating biomass and that for a given number of tagged fish available a minimum numbers of recaptures are required to ensure a low likelihood of biomass overestimation. For Chapman-estimates to achieve a 25% level of accuracy at least 50% of the time, required a minimum of 6 recaptures when there were approximately 270 tagged fish available for recapture. To increase the chance of achieving the same level of accuracy to 80%, a minimum of 20 tagged fish recaptures were required when approximately 815 tagged fish were available.

The minimum number of recaptures required to achieve a specified level of accuracy will vary depending on the initial population size, the exploitation and tagging rate and the consequent number of tagged fish available. Simulations of toothfish populations could be performed for all Research Blocks to assess the data requirements to obtain Chapman estimates with a high likelihood of being within a desired level of accuracy. Based on these simulations, the Working Group consider developing criteria such as a minimum number of annual tag-recaptures required in each Research Block to determine when it is appropriate to use a tag-based estimate of biomass.

This study has used bootstrap methodology to quantify the uncertainty in toothfish biomass estimates from Chapman mark-recapture and the CPUE-by-seabed area methods in Research Blocks in Subareas 58.4 and 48.6. The Chapman mark-recapture point estimates and their confidence intervals were generally much larger than the point estimates and confidence intervals from the CPUE-by-seabed area biomass estimates.

For Patagonian toothfish in Subarea 58.4 the confidence intervals of both methods overlapped in most years, providing some confidence in the estimates from the two different methods. The large differences in Antarctic toothfish biomass estimates using the two different methods suggests that the underlying assumptions currently made in one or both of the methods are likely to be invalid.

We recommend that Working Group consider reviewing assumptions in the CPUE-by-seabed area and the Chapman biomass estimation methods at the Research Block scale and prioritise resolving issues in Research Blocks that show the largest discrepancies. 

This paper reports the preliminary results of by-catch analysis as a part of progress report for the research fishery of Dissostichus spp. in Division 58.4.3a and 58.4.4b by Japan and France during 2012/13–2016/17. We have used extracted data provided by CCAMLR secretariat on 2^nd June, 2017.

Although the by-catch occurred in most longline research operations, the number of by-catch individuals was less than 50 individuals in most of the operations. In most of longline operation, by-catch weight was less than 100 kg and less than 20 % of total catch. GRV and ANT are common by-catch species, which are caught at every research block and every year. RFA is also common by-catch species, but mainly fished at the research block 58.4.3a.

The results of the GLM and its model selection with AIC criteria indicates that the number of by-catch individuals is highest at the research block 58.4.4b_1 for GRV and ANT. As temporal change of by-catch, common three by-catch species represents obvious decrease in number of by-catch individuals. The results of GLMs also imply the influence of fishing method and gears on the by-catch pattern.

This paper reports the preliminary results of by-catch analysis as a part of progress report for the research fishery of Dissostichus spp. in Subarea 48.6 by Japan and South Africa during 2012/13–2016/17. We have used data set provided by CCAMLR secretariat on 10^th May, 2017.

Although the by-catch occurred in most longline research operations, the number of by-catch individuals was less than 100 individuals in most of the operations. In most of longline operation, by-catch weight was less than 100 kg and less than 20 % of total catch. GRV and ANT are common by-catch species, which are caught at every research block and every year. ICX is also common by-catch species, but mainly fished at the ice ridge research blocks 48.6_4 and 48.6_5.

The results of the GLM and its model selection with AIC criteria indicates that the number of by-catch GRV individuals is higher at southern research blocks (48.6_3, 48.6_4, and 48.6_5). On the other hands, the number of ANT by-catch individuals is highest at research blocks 48.6_1. As temporal change of by-catch, only GRV shows obvious decrease in number of by-catch individuals.

The subarea 88.3 is a large area contained from 105° W to 70° W where has been closed to directed fishing following the results of a Chilean survey activities in 1998 (SC-CCAMLR-XVII/BG/7). Previous three research surveys conducted by the New Zealand and the Russian flagged vessels since 1998. It was noted that 8 D. Mawsoni were tagged by the New Zealand in the 2004/05 season and 123 D. Mawsoni were tagged by Russian flagged vessels in the 2010/11 and 2011/12 season (WG-FSA-05/53, WG-FSA-11/36 & WG-FSA-12/13). It was also noted that no tagged fishes were recaptured during the previous research activities. Considering this large region, the Republic of Korea notes that only 95 research hauls and 131 tagged fishes from three research activities (in total since 1998) were not enough likely to recapture. it was further noted that there was no research activities more than two consecutive years in the past despite the Scientific Committee has agreed that research fishing should be conducted such that it results in an assessment of a stock in 3-4 years time (SC-CAMLR XXVIII, paragraphs 4.165). During the 2016/17 season the Korean flagged vessel, Greenstar, conducted 2^nd year research in this area. Total of 957 D. Mawsoni were tagged and released. Although the Greenstar set 95 research hauls in the Subarea 88.3 she did not find any recaptures of previous surveys. In third research year, the Greenstar is planning to revisit to the areas where the tagged fishes were released to further understand toothfish movement and migration with recapture data.

The Ross Sea region MPA Research and Monitoring Plan Workshop (WS-RMP) was held at the Palazzo Farnesina (Ministry of Foreign Affairs and International Cooperation, MAECI) in Rome from 26–28 April 2017.

The purpose of the workshop was to develop a draft research and monitoring plan (RMP) for the Ross Sea region MPA. The RMP is required to be introduced to CCAMLR at the annual meetings of the Scientific Committee and Commission later this year, prior to the Ross Sea Region MPA’s implementation in December 2017.

Following the workshop, the conveners submitted the draft research and monitoring plan to the Ross Sea MPA implementation e-group. Since then, two comments have been submitted to either the e-group or to the conveners directly. These comments attached at the end of this document.

The Antarctic toothfish stock assessment for the Ross Sea region (Subareas 88.1 and 88.2AB) will be updated in 2017. The introduction of CM 91-05 (the Ross Sea region Marine Protected Area) will require modifications to the previous method the estimation of catch splits in the calculation of precautionary yields. In addition, work will need to be carried out in the longer term that consider how the assessment will need to be modified to respond to changes in the fishing catch and effort distributions that may result from the implementation of the Ross Sea region MPA.

An update of the 2015 stock assessment is proposed for the 2017 stock assessment which will maintain the current structure of the model while including updated catch, age-frequency, and tag-release and recapture data. Yield projections should be run that incorporate short term catch split options as required by CM 91-05. Additional options could also be developed for catch splits between the shelf, slope and north areas prior to the 2019 assessment. Sensitivities to a base case model that investigate the robustness of model assumptions or arise from the considerations of model diagnostics should also be conducted.

The Amundsen Sea region (ASR) is currently managed under a research plan, which has shown promising results to date, with 8 interseason tags recaptured in the South area in 2016 and 12 (preliminary recaptures) in 2017. The aim of this paper is to ascertain when the Amundsen Sea region stock assessment model is likely to provide management advice, and to investigate the effects of using either two independent single-area models or a two-area model.

We used simulations to investigate the expected precision in estimates of biomass, the likely biases, and to set expectations for mark-recapture data for the next few years to predict progress towards a robust assessment model using the two-area model. The models showed that using two independent models lead to higher estimates of biomass in the North and lower estimates of biomass in the South, but that the two independent models fitted the data poorly. Simulations suggest that the current research plan with the current levels of catch and tagging rate is likely to deliver the information that would generate a robust estimate of biomass in the ASR in the future. We also found that it is likely that we would observe very few tags moving between the areas and that increasing the tagging rate in the South would result in an increase in bias but no improvement in the precision of the estimation of stock biomass.

We therefore recommend (i) future work using independent methods to understand toothfish movement within the ASR (such as PSAT tags or otolith microchemistry), and (ii) the current research plan be continued for the next season, and (iii) a two-area model continue to be developed to assess the ASR for 2018, as recommended by Scientific Committee in 2016.