CCAMLR

Photographs of skates taken by observers on New Zealand toothfish longliners in the Ross Sea were identified to species. Sample sizes were small, but indicated a ratio of 10.75:1 of Amblyraja georgiana to B. cf. eatonii, which is consistent with a previous estimate based on a large sample of tagged skates. Biological parameters were reviewed and updated for Amblyraja georgiana. Revised length-weight regression relationships for male and female A. georgiana confirmed that male and female relationships differ significantly. Better estimates of median length at maturity were made possible through a combination of improved observer staging of skates, and a moderate-sized sample of whole skates that was examined in the laboratory. There was no significant difference between the median length at maturity for male and female A. georgiana, which was estimated to be 67.3 cm pelvic length (= 96.5 cm total length). Nearly all of the skates caught were returned to the sea (discarded or tagged). A considerable proportion of these were returned in good condition and were considered likely to survive. Estimates of the proportion released in good condition are in the range 50–80%, depending on assumptions about whether skates were double counted, and whether all tagged skates were in good condition. Improved data recording using new fate and condition classes and a new data logsheet should provide better estimates of this parameter next year.

Conservation Measure 22-06, in the absence of site-specific or other conservation measures to prevent significant adverse impact on vulnerable marine ecosystems, requires specific actions to be taken when evidence of a Vulnerable Marine Ecosystem (VME) is encountered in the course of fishing operations. Monitoring fishing operations for encounters with evidence of a potential VME entails identification of specific taxonomic groups of invertebrates, such as sponges or corals. Identification of these organisms to the appropriate taxonomic grouping has not been a standard procedure, and no identification guide specific to both indicative VME taxa and Antarctic species has been developed. The objective of this guide is to provide observers on long-line vessels with a potential VME-taxa specific, quick, on-deck guide to aid in the classification of invertebrate bycatch into the appropriate groupings. The format of the guide is a “compare and contrast table”, using photographs and key characteristics to correctly classify likely VME taxa to the appropriate grouping. It also identifies those commonly mistaken for other taxa. It is printed as an A2 waterproof poster for display in the vessel factory or on deck for easy reference. Once classified, these observations can be used for monitoring evidence of a potential VME. Additional invertebrate identification guides are still needed for fine taxonomic resolution for all invertebrate bycatch.

The Ross Sea has been geologically characterized by tectonic and glacial processes. These processes have created diverse habitat, including distinct banks and basins. For many fish species the availability of habitat is critical to the long-term viability of the population. Antarctic toothfish (Dissostichus mawsoni) are subject to an increasingly important commercial fishery in the Ross Sea and yet little is known about habitat associations for different life history stages. To define and assess the availability of habitat for Antarctic toothfish a benthic habitat map of the Ross Sea was created based on the habitat mapping scheme developed by Greene et al. (1999). Fish age data from the long-line fishery in the Ross Sea were superimposed on the habitat map and broken into discrete spatial areas. Differences in age distributions between these areas were found using ANOVA. These distributions were consistent with an ontogenetic movement of fish from shallow continental shelf habitats to deep-water continental slope was documented. Younger, less mature fish were located on the continental shelf and older fish were located on the continental slope. In addition, the older and most mature individuals were found on ridges in the northern Ross Sea, consistent with the hypothesis of an austral summer spawning migration from continental slope to the ridge habitat of the North Ross Sea. An effective management strategy might focus on protecting the northern ridge habitat to maintain long-term viability of Antarctic toothfish populations.

Antarctic toothfish (Dissostichus mawsoni) are subject to an increasingly important commercial fishery in the Southern Ocean, yet many of their life history characteristics, including vital rates, remain unknown. In this study, Antarctic toothfish were aged using otolith age estimation criteria established for Patagonian toothfish, D. eleginoides, a closely related species. To validate estimated ages, the radioactive disequilibrium of lead-210 and radium-226 in otolith cores was measured and used as an independent chronometer to determine age. Age estimates indicated Antarctic toothfish live to at least 39 years of age. Estimated and radiometric ages were in close agreement, confirming age estimation criteria and an annual periodicity of otolith growth zones. Von Bertalanffy growth function parameters indicate Antarctic toothfish are relatively slow-growing (k = 0.111; t0 = -0.605), especially in relation to their maximum size (L∞ = 158.9 cm). These vital rates are discussed in the context of the growing Antarctic toothfish fishery.

The Uruguayan-flagged longliner Banzare experienced sea-ice related, operational difficulties in implementing the CCAMLR Tagging Protocol in Division 58.4.1 in 2007/08. Extensive sea-ice cover greatly increased the transit times between research haul locations, which resulted in long soak times and a high mortality rate of fish on these lines; only fish with a high chance of survival were tagged. In brief: • The vessel started fishing in Division 58.4.1 SSRU E on 6 January 2008 but only completed one haul (no catch) due to adverse ice conditions, and the vessel exited that Division; • The vessel returned to Division 58.4.1 SSRU C and resumed fishing on 27 January 2008, completing 16 hauls including 10 research hauls. The vessel then moved to SSRU E on 3 February 2008 and completed 3 hauls (note: SSRU G was closed on 30 January 2008). • The vessel caught a total of 9.757 t of Dissostichus mawsoni in Division 58.4.1 and tagged and released 10 fish (tagging rate: 1.02 fish/tonne), which was below the tagging rate of 3 fish tagged per tonne of green weight caught required in Conservation Measure 41-11(2007). The vessel and authorities were aware that the extensive sea-ice cover had prevented the vessel from tagging fish in Division 58.4.1 at the rate required by CCAMLR. As a result, the vessel made every effort to tag fish in excess of the required rate when the opportunity arose: • in Division 58.4.3a the vessel tagged fish at a rate of 4.9 fish/tonne; • in Division 58.4.3b the vessel tagged fish at a rate of 4.6 fish/tonne;

On the results of some field materials collected from 2002 till 2008, on the basis of length composition analysis of individuals, weight of females’ gonads and sex ratio an attempt was made to select locations and periods of Antarctic toothfish mass spawning in some areas of the Pacific Ocean and Indian Ocean sectors of the Antarctic. In the Ross Sea area the most probable areas are the Pacific Antarctic Ridge and the Amundsen Ridge in the Amundsen Sea area. In the Cooperation Sea area the most possible mass spawning place is the Banzare Bank. Obviously, the mass spawning is stretched and falls on the winter season, sometimes covering part of autumn or spring season.

Two species of deep-sea skates (Rajidae, Chondrichthyes) are newly recorded from the slope of the Crozet Archipelago. Specimens are preserved in collections, morpho-anatomical observations and molecular Barcoding are currently in process to identify that species.

Scientific data were obtained during the fishery cruise of Spanish long-liner «Tronio» in the areas of the Ross Sea and the Antarctic continental shelf (statistical subareas 88.1 and 58.4.1) outside the exclusive (marine) economic zones of foreign states, in the period from 5 November, 2007 till 24 March, 2008. In the paper size characteristics of Antarctic and Patagonian toothfishes caught in different areas of the Antarctic shelf were given as well as characteristics of maturity level of gonads and nutrition of the examined fish.

We conducted a survey to investigate the factors influencing the number of seabirds attending a research vessel during scientific trawling activities near the northern Antarctic Peninsula. Our objective was to assess whether seabirds exhibited differing levels of attendance that may be attributed to fishing activity. Counts of seabirds attending the vessel were made during non-fishing periods, net deployment, towing, and retrieving. We also monitored environmental variables (e.g., pressure, wind speed and direction) and discards of fish and offal to determine whether they could be used to explain variability in seabird attendance. Three species, the Black-browed Albatross Thalassarche melanophrys, Cape Petrel Daption capense and Wilson’s Storm Petrel Oceanites oceanicus were the most common seabirds attending the vessel. We found that abundance of seabirds did not differ among fishing activities, although the presence of discard caused an increase in numbers of petrels and albatrosses. Our study is the first to examine seabird-vessel attendance to scientific trawling activities in Antarctic waters where there is a moratorium on commercial finfish fishing. By comparison to other studies, the level of fishing conducted during this study is not anywhere near that of commercial fishing (i.e., catch rate and fishing duration). Nevertheless, it is important to monitor seabird attendance to fishing vessels so that proper mitigation and conservation actions are met to protect seabirds.