CCAMLR

In January 2010, the UK carried out the annual groundfish survey in CCAMLR Sub-Area 48.3 on the FV Sil. Seventy-five random hauls were completed with good coverage across the shelf, representing an increase in effort overall compared with surveys carried out in 2008 and 2009 on the same vessel. Catch-weighted length frequencies of mackerel icefish indicated that although 3+ sized fish dominated the population, 2+ and 1+ sized fish were also present, and in larger proportions than in 2009. A mean biomass of 52,329 tonnes was estimated for mackerel icefish, with a lower 1-sided 95% CL of 24,334 tonnes, an increase on the biomass estimate for 2009. Considering the anomalous environmental conditions and low availability of krill to mackerel icefish in the area (evidenced by dietary analysis) in 2009, this increase in biomass was unexpected. The importance of krill in the mackerel icefish diets was greater in 2010 than in 2009 but still remained low compared to historical data, and Themisto gaudichaudii dominated diets in Northern area strata where the largest numbers of mackerel icefish were caught. As seen during the 2009 survey, mackerel icefish remained close to the bottom and very few acoustic marks were observed in the water column during the survey. Catches of Patagonian toothfish were greater than in 2009, but still low compared with historical survey catches. There was however, the first evidence since 2003/04 of a recent recruitment of evident at Shag Rocks, with presence of putative age 2+ fish (29-39cm). Very large catches of marble rockcod were experienced during the 2010 survey, with increased catches across all areas of shelf surveyed around South Georgia and Shag Rocks compared with previous surveys. The mean biomass estimate was 173,223 tonnes, more than ten-fold the estimate for 2008. Catches and biomass estimates for Scotia Sea icefish and South Georgia icefish were also greater than estimates for 2008 and 2009. Exploration of historical marble rockcod catch data and environmental variables is underway, but careful monitoring of all three species should be carried out to determine whether these estimates represent population recovery.

A length based projection model is employed to estimate catch limits for the 2011/12 fishing season for Champsocephalus gunnari in CCAMLR sub area 48.3. The model is initialised using estimated numbers at length derived from survey length  density and biomass density data, removing the need for cohort identification associated with the age based projection model used in previous assessments. Application of the harvest control rule ensuring 75% escapement after a two year projection period yielded a total allowable catch of 2349 tonnes.

The analysis of catch size composition, statistical data on catches and distribution of Antarctic tooth-fish, and tagging data showed that the existing system of fishing subarea partition into SSRUs, open and closed for fishery, resulted in a lack of overall picture of population structure state, quantitative toothfish distribution over the whole aquatory in Divisions 88.1 and 58.4 and did not give an idea of toothfish migrations by tagging results. The mentioned system shortcomings require its revision and conducting of fishery, investigations on toothfish distribution over the whole areal and account of the stock state.

This research makes a contribution to the Agenda Item 8 of the WG-FSA. (Biology, ecology and demography of target and by-catch species) and shows the response of the local population of Dissostichus eleginoides (TOP) from the Area management A (subarea 48.3), after 4 year of closure (2004 to 2008). We noted an increase in the CPUE overtime, mainly associate with the increase in the median size of fish caught, at a mean rate of approximately 1 kg per year/per individual. This result suggests that the sampling in this area should not stop because of its high interest in the monitoring of the recovery of the spawning biomass of the local population in relation to the BOFFFF hypothesis (Big Old Fat Fecund Female Fish), which is very important for strengthening CCAMLR precautionary management in this species.

This paper describes spatial and bathymetric distribution of fish bycatches inside the French EEZ for the longline fishery.

The genus Macrourus is a small group of bentho-pelagic fishes with three species recognized in the Southern Ocean and one in cold temperate to Arctic waters in the North Atlantic Ocean. DNA barcoding revealed low intra-species (0.0-0.002) and inter-species (0.006-0.020) sequence divergences, with four well supported clades among the three Southern Ocean species. Additional specimens collected in the Ross Sea region, and provisionally identified as M. whitsoni, were divided into two COI haplotypes, based on a Restriction Fragment Length Polymorphism (RFLP) test. Three characters counted/scored in the same Ross Sea region specimens classified individuals into two groups: one with 9 pelvic fin rays, pale body colour, and a single row of relatively long teeth, and a second group with 8 pelvic fin rays, dark body colour, and 2 or more rows of finer teeth, that corresponded with the DNA haplotypes. The COI divergence coupled with the meristic and morphometric differences among specimens provisionally identified as M. whitsoni from the Ross Sea region provided strong evidence for two sympatric species: M. whitsoni pale and M. sp dark. The shallow sequence divergences likely indicate either recent evolutionary divergence or slow nucleotide substitution at COI in this genus.

Data are collected for use in scientific research, the results of which are used to inform management decisions made to achieve specific goals. Any data collection plan should be drawn from the goals the management wishes to achieve. The Scientific Committee has recommended the development of a specific data collection and research plan for the Subarea 88.1 and 88.2 fisheries (SC-CCAMLRXXVII paragraph 4.160 vi). The long-term goals of the Ross Sea fishery based on Article II of CAMLR can be summarised as: the target fished population is above a level which ensures stable recruitment; the ecological relationships between harvested, dependent, and related populations are maintained; and, prevention of changes or minimisation of the risk of changes in the marine ecosystem which are not potentially reversible over two or three decades, with the aim of making possible the sustained conservation of Antarctic marine living resources. Based on these goals and previous experience in the fishery, proposed medium term research objectives for the Ross Sea fishery for the next 5–7 years were developed in 2008. The outlined medium-term research objectives were used as the basis for the development of this Ross Sea region fisheries medium term data collection plan. This paper provides context with a brief summary of recent science, summarises the current fishery-dependent data collection, describes the proposed medium term research objectives, and develops an associated draft fishery-dependent medium term data collection plan. Feedback is sought from WG-FSA and TASO, in particular are there any substantive gaps in the proposed data collection requirements and can any feedback be provided on the approaches to optimising sampling rates, the proposed rotational approach to sampling certain species and which data collection could be undertaken by vessels and which data collection should be undertaken by observers.

ABSTRACT Since 2008 New Zealand has been developing an impact assessment framework to estimate the likely impacts of bottom longline fishing on Vulnerable Marine Ecosystems (VMEs), as required by Conservation Measure 22-06. The most recent iteration of the impact assessment (Sharp 2010) was recommended in 2010 by WG-SAM (paragraph 4.16) and WG-EMM (paragraph 3.20) as the basis by which Members submitting new and exploratory fishery notifications should estimate impacts on VMEs associated with their proposed bottom fishing activities, as well as the basis by which WG-FSA might complete cumulative impact assessments for all gear types combined at the scale of entire fisheries. Both WG-SAM and WG-EMM gave specific guidance as to how the framework might best be applied. This paper updates the impact assessment taking account of the specific recommendations of WG-SAM and WG-EMM 2010 and incorporating new information arising from WG-EMM 10/33, including the choice of improved input distributions representing key variables driving the impact simulation and the use of alternate assumptions in which lateral movement frequency is negatively correlated with depth. Impact estimates are summarized separately for each of 17 benthic bioregions defined in Sharp et al. (2010), and displayed as frequency distributions of fine-scale pixels experiencing different levels of impact, as advised by WG-SAM 2010 (paragraph 4.18). We conclude that the relationship between depth and lateral line movement is highly uncertain, but it is likely that improved understanding of this relationship will yield impact estimates that are slightly higher for shallow habitats on the shelf relative to previous estimates, and substantially lower for deep habitats. Overall estimates of impact remain low within all bioregions.

High resolution VME taxa bycatch data (at the longline segment level) have been collected for two fishing seasons, with 4 728 longline segments observed. Several regions with consistent presence of VME taxa bycatch are identifiable, as are several areas of dense fishing effort with no evidence of VME taxa. Identifiable sponge and/or gorgonian habitats occurred at a typical scale of 10-30 km², though some sponge habitats may have been larger. Other taxa were not clustered at small scales, but were at larger scales. Spatial analysis of these data allows the detectability of prevalent taxa to be estimated, along with changes in catch rate at different levels of observed bycatch. Results indicate that several VME taxa are detected between 60% and 80% of the time when present, and that probability of detection was higher near areas with other high bycatch observations. Video transects on the Ross Sea slope from New Zealand’s 2008 IPY voyage were used to characterise the fine scale distributions (i.e. < 600 m) of sponges, stony corals, and ascidians. The prevalence of six VME taxa also varies among four benthic bioregions developed for the Ross Sea. Together, the data show that vulnerable taxa occur in complex mosaic patterns of small patches dispersed within larger habitats. Confirmation of these results is necessary using independent methods such as underwater video and would provide a method to link bycatch observations to habitat density on the seafloor.

An important management objective for CCAMLR in the high seas region of the Antarctic is to develop appropriate methods of monitoring and managing impacts of bottom fisheries on vulnerable marine ecosystems (VMEs). We describe a spatially explicit production model that can be used to investigate a range of scenarios for simulating the effect and management of benthic impacts from longline fishing effort. Further, we update this paper with a set of simulations using a range of simple and extreme case studies to validate the underlying model and code. In general, the model simulations were carried out under a range of productivity assumptions, impact, and spatial scale, with and without management by areal closures. The management action simulated considered a range of areal closure radii and bycatch trigger thresholds. We conclude that spatially explicit production models can provide a useful tool for the investigation of impacts of fishing effort on benthic organisms. They have the advantage that they are relatively simple to construct, run, and interpret. In most cases, the results of the simulations suggested that management action of areal closures in the Ross Sea region are likely to result in an improved outcome relative to scenarios where there was no management action, but that the magnitude of simulated impacts under the plausible models was often very small. We also note that further work on these simulations are required — including investigating how changes in the distribution of future fishing may influence estimated impacts or how different assumptions of the underlying distributions of benthic organisms may influence recovery or management effectiveness. However, as the magnitude of these impacts in the scenarios tested were small, we recommend that research be focused, at least in the short term, to provide the observational or experimental data necessary to constrain important model parameters, to reduce uncertainty and provide more plausible scenarios.