CCAMLR

To explore the potential effects of the toothfish fishery on the population dynamics of Antarctic toothfish and its main prey, grenadiers (Macrouridae) and icefish (Channichthyidae), we develop a spatially explicit model using a predator-prey suitability model for the Ross Sea Region. We model the age-based population dynamics of toothfish, grenadier, and icefish, and include natural mortality (M1) and predation mortality (M2), in addition to fishing mortality (F) on all three species. The model suggests that the predation release caused by the fishery effect on toothfish abundance is greater than the direct fishing mortality on both prey species and that icefish is expected to show a larger increase in biomass through time than grenadiers. It also suggests that a prey-suitability function is more likely than a Holling type II function to describe the predatory relationships in the model. We use the model to compare the predicted population changes with available abundance data for each species to develop hypotheses of the nature of the interaction. Whilst this model is in a development stage, it provides a useful tool for evaluating potential impacts of the fishery on key prey species, and for assessing and designing monitoring tools for fish species associated with the toothfish fishery. We recommend targeted sampling of toothfish for diet analysis, and the monitoring of icefish and grenadier populations in SSRUs 88.1H and 88.1K through the development of age frequencies (length measurements and aging).

Stable isotopes of carbon and nitrogen (δ¹⁵N and δ¹³C) in Antarctic toothfish (Dissostichus mawsoni) muscle were measured to study the trophic connections of Antarctic toothfish in the Ross and Amundsen Sea regions (CCAMLR Subareas 88.1 and SSRU 88.2H respectively). More than 1700 toothfish were sampled by scientific observers on New Zealand vessels between 2005/06 and 2013/14. More than 100 samples each of four by-catch species (grenadiers, icefish, moray cods and deep-sea cod) were also analysed, but only from the Ross Sea region. Appropriate corrections were made to account for the effect of lipid in muscle on δ¹³C in a way that did not compromise the accuracy of δ¹⁵N measurements. We found considerable variability in δ¹⁵N and δ¹³C of toothfish that were not explained by fish length, sex, location, depth or year of capture. We found statistically significant but small relationships between δ¹⁵N and fish length, region, and year: (1) on average, larger toothfish fed on prey of higher trophic level; (2) δ¹⁵N values of toothfish on the Ross Sea slope were lower (~0.8‰ between medians) than in other areas (northern Ross Sea seamounts, Ross Sea shelf and 88.2H); (3) after allowing for fish length, sex, and location, there was a small but significant reduction in δ¹⁵N values (0.3‰) between 2010 and 2014. This study found that δ¹³C values of toothfish in the Amundsen Sea region were substantially higher than in the Ross Sea region (medians differed by 1.4‰). This result implies that most of toothfish sampled from the Amundsen Sea had not mixed with fish from the Ross Sea region for the 6 months – 2 years before capture (the likely turnover time of protein in fish muscle). The result is consistent with different spawning populations in the two regions. In the north and slope areas of the Ross Sea, “prey polygons” were used to investigate whether δ¹⁵N and δ¹³C values for toothfish were consistent with isotope values for the likely main prey species, assuming standard trophic fractionation factors. For the Ross Sea slope region, the predator-prey polygon largely enclosed the toothfish isotope values, indicating that the by-catch species caught the same area could have comprised most of the toothfish diet. However, the predator and prey isotope data were inconsistent for the northern seamount region because δ¹³C for by-catch species were higher in the north than the slope area of the Ross Sea, but δ¹³C for toothfish were similar in the two areas. The reason for this difference is as yet unclear but is consistent with toothfish feeding at a low rate in the northern Ross Sea area and staying there for less than a year.

In previous years we revealed that period 2006-2011 is characterized by the highest values of standardized CPUE indices in the Subarea 48.1 for the last 25 years. We continue to investigate krill fishery data for understanding reasons of this ‘high CPUE’ regime. The authors present the analysis of spatial - temporal variability of krill fishery based on CPUE trends, trawling duration, catch per haul, fishing efforts (hours fished) and vessel locations for traditional and continuous fishing methods. Our investigation shows how fishery operated by years and month in each SSMUs with special attention to differences between national fleets. It was shown also significant variability in fishing indices based on different fishing methods as well as between national fleets using traditional fishing method.

We obtained the additional evidence that ‘high CPUE’ regime’ in 2006-2011 is not associated with the changes in fishing methods but is result of the influence of changing environment. Impact of fishing methods on fleet locations was not revealed also.    

Our opinion is that climate changes can become the reason for the changes in sea ice locations and krill abundance and distribution affecting fishery strategy and performance. The important evidence of above said is the СPUE regimes switching observed in long-term fishery.

We suggest that information on variability of krill fishable biomass distribution in connection to the fishery performance will promote important platform for developing feedback management procedures for krill fishery in Subarea 48.1 as well as in Area 48. The source of this information should be acoustic surveys and observations onboard krill fishing vessels.

A National Workshop on CCAMLR MPAs was conducted at Valparaiso, Chile, 13-14 May 2014. Main points discussed were the significance of each conservation objective for the process, the best way to implement each objective in the analysis and data gaps. Outputs of the workshop are expected to contribute to the general discussion on MPA planning for Domain 1.

Presented Annex 21-03/A as required by Conservation Measure 21-03 with set nets configuration and scheme of marine mammal exclusion device.

Ground counts during 1959-1968 compared with counts using high resolution satellite imagery during 2008-2012 indicated many fewer Weddell seals (Leptonychotes weddellii) at the two major molting haul outs in the western Ross Sea: Edisto Inlet - Moubray Bay, northern Victoria Land, and southeastern McMurdo Sound, southern Victoria Land. Breeding seals have apparently all but disappeared from Edisto-Moubray as well. The timing of decline, or perhaps spreading (low numbers of seals in more places), is unknown but appears unrelated to changes in sea ice conditions, which was our initial hypothesis. We analyzed both historic and satellite-derived ice data but found only an expansion of pack ice in the larger region and a thinning of fast ice along Victoria Land (conceivably beneficial to seals). Timing of freeze and breakup of the fast ice remains the same. The only other major change to the Ross Sea ecosystem that would have negatively affected seals has been the large-scale removal of large Antarctic toothfish (Dissostichus mawsoni), a major prey, by a fishery operating full scale by 2003. Coincident with the fishery, lower numbers and size of toothfish have been reported in McMurdo Sound and data from seals tracked by satellite indicate wider foraging range during winter than 20 years ago. A large-scale seal monitoring program is required to prove that the fishery is not involved.

What is the spatial scale of monitoring conducted at an individual CCAMLR Ecosystem Monitoring Program (CEMP) site? Answering this question is key to understanding how CEMP data could be used in a feedback management strategy and for identifying critical gaps in monitoring effort where new monitoring effort may be useful. Toward this goal, we investigated data sets from two Pygoscelid penguin species that are monitored at three sites on King George Island/Isla 25 de Mayo, within 30km of one another. We used five indices that fall under three main categories of census (breeders and chicks), reproductive success (crèche rates), and chick growth (fledge weights). We found strong positive correlations across sites in census data, implying similar information is being collected at all three sites. We also found evidence of and site- and species-specific differences that highlight heterogeneity in indices of reproductive success and chick growth on local scales. Heterogeneity on such a small spatial scales suggests the need for CEMP monitoring to be distributed widely to encapsulate population responses to changing environments and fishing activity. Within a broad network of CEMP monitoring, it may also be useful to have several monitoring clusters like that on King George Island to help identify the relative importance of local environmental factors and better estimate the range of variability that such factors can introduce into CEMP indices; partitioning such variability seems critical for resolving environmental and fishery impacts on monitored predators.

This report presents the results of the second workshop for identifying Marine Protected Areas (MPAs) in Domain 1 of CCAMLR. The results of the first Workshop were presented in WG-EMM-12/69.

This second workshop was organized as bilateral meeting between Chile and Argentina in order to review the progress achieved since the first international workshop held at Valparaíso in 2012. The list of assistants is provided in Annex 1. The workshop was held at La Serena, Chile, between 2-4 September 2013.

We compare the diet and the foraging distribution of Adélie penguins at Hope Bay/Esperanza, during the late part of the breeding season and their subsequent post breeding dispersal in two consecutive years. We also compare data from the krill fishery to describe Adélie penguin foraging areas with krill fishery activity at spatial and temporal scale.

During both seasons, the bulk of the diet was represented by krill. Foraging locations during the breeding period were concentrated to the west of the colony and in the northern Bransfield Strait/Mar de la Flota in both years. During the pre-moulting period, Adélie penguins dispersed away from the colony and foraged further to the east in the northern Weddell Sea up to 400 km from the colony. During the breeding period of 2013, Adélie foraging areas and fishery activity showed an overlap in both temporal and spatial scale; no such direct overlap was apparent during the following season.

Our results showed that foraging areas during breeding and postbreeding dispersal are consistent across years, suggesting that the Bransfield - Weddell shift region is an important feeding area for Adélie penguins breeding in the tip of the Antarctic Peninsula.

More than 100 research SCUBA-dives to depths till 60 meters (2003-2004), and more than 40 research SCUBA-dives to depth till 50 meters (2011-2012) was provided. During the summer season of the 19th Ukrainian Antarctic expedition in 2014 twenty research SCUBA-dives were carried out during which a survey of the two already proposed MPAs was provided. For a further development of Marine Protected Area Network it is necessary for each area to establish a category in accordance with the procedure IUCN. Planned to research two areas: “Stella Creek” and “Skua Creek”.