CCAMLR

1. The Secretariat manages a comprehensive, detailed set of independent or related databases which support the work of the Commission and give effect to Article XX of the CAMLR Convention. Since the establishment of CCAMLR 28 years ago, there has been no formal, in-depth audit of the Secretariat’s data management systems against international best practice. 2. The Working Group is invited to consider the merits of an independent review of CCAMLR’s data management systems.

ABSTRACT Applicability of geostatistical methods in processing the acoustic fields of krill density based on the acoustic survey data is demonstrated. The results obtained indicate usefulness of these methods in studying the structure of krill density field for biomass assessment in compliance with different thresholds of their fishery importance. The structure of krill density field in Subarea 48.3 based on the surveys 2000 and 2002 indicates that krill fishable biomass is concentrated in small areas and constitutes only part of the total biomass concentrated within each coastal SSMU (SGW, SGE) in Subarea 48.3. The ratio between fishable biomass and total krill biomass may vary considerably by years and SSMUs reflecting inter-annual fluctuations of the krill density field structure. Keywords: acoustic survey, geostatistical methods, fishable biomass, density thresholds.

The task to estimate the escape mortality of krill during the fishing operation assigned by Scientific Committee requires assessment of the total krill passed through the rope and netting parts of trawl and krill amount appeared unviable in the process of escapement. The recommendations presented are the first attempt to develop the method of instrumental assessment of the «escape mortality». Estimation of the total amount of krill escaped from the rope and netting parts of the trawl is proposed to carry out on the basis of the complex application of fine-meshed chafers and acoustic method. The method of fine-meshed chafers allows obtaining the quantitative assessment of krill killed during escapement from the trawl. However, the practical implementation of fine-meshed chafers requires special investigation on methodical and technological issues of estimating krill escape mortality. The problems and approaches to elaboration of the efficient method for «escape mortality» study by standardizing data collection and processing, including a standard chafer design, are discussed. Keywords: escape mortality, method of fine-meshed chafers, acoustic methods, krill injury rate, krill viability.

ABSTRACT
Two new procedures are currently been developed by the Secretariat to further improve data quality: (1) validation of species’ spatial distributions; and (2) visualisation of data from single fishing trips. Both procedures are outlined.

ABSTRACT
Prior to the 2009/10 fishing season, the Secretariat allocated starting positions for research hauls in the exploratory fisheries in Subareas 48.6 and 58.4 (except on BANZARE Bank were positions were specified in Conservation Measure 41-07). For each of the 12 notifying vessels, up to 8 starting positions were provided for each stratum in each SSRU notified, and vessels were required to complete 5 research hauls in each stratum (total of 10 research hauls per SSRU). In all, 1133 starting positions were allocated for 84 vessel-SSRU combinations. As of June 2010, three vessels had fished in these exploratory fisheries in 2009/10, and had deployed a total of 129 research hauls in accordance with the conservation measures and allocated positions. Overall the vessels adhered to the research fishing protocol. Three types of difficulties and/or limitations were evident :

a) Sea-ice along the Antarctic coastline had prevented some vessels from reaching allocated positions in the continental SSRUs (e.g. 486D, 5841C and 5841G); however, the vessels were able to deploy research hauls in alternative positions determined by vessels.

b) The deployment of research hauls in alternative positions determined by vessels had resulted in some hauls being set in depths greater than 2500 m.

C) Some vessels did not achieve the required 5 hauls per stratum.

Observer data collected on longliners between 2003 and 2009 were analysed to look at the levels of depredation caused by killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus) around South Georgia. Since 2003, cetaceans have been observed on 22% of 14 300 observed lines, with killer whales present on 3.8% and sperm whales on 17.7% of lines. Killer whales appear in pod sizes normally of 4 to 10 animals, and often appear to actively seek out fishing vessels and ‘strip’ the line of a large number of toothfish, usually depressing CPUE by about 50%. Sperm whales occur in smaller pod sizes, normally between 1 and 4 animals and have a relatively lower impact on catches, depressing CPUE by up to 20%. Sperm whales have been more frequently encountered in recent years, occurring in larger pod sizes, whereas killer whale encounters and pod sizes have remained relatively constant. Most interactions from sperm whales occur during May at the start of the season with the sightings becoming fewer towards the end of the season in August. Killer whale interactions appear to be more consistent with no obvious pattern between months. Both species demonstrate an east to west migration throughout the season that is not related to the pattern of fishing effort. By comparing catch rates with and without the presence of cetaceans, accounting for other determinants of toothfish CPUE through a generalised linear model, it is estimated that the amounts of toothfish removed from longlines by cetaceans have varied between 1% and 8% of the declared catches over the period 2003–2009, with an average of 3.6%.

Patagonian toothfish (Dissostichus eleginoides) is a large notothenioid fish that supports valuable fisheries throughout the Southern Ocean. D. eleginoides are found on the southern shelves and slopes of South America and around the sub-Antarctic islands of the Southern Ocean. Patagonian toothfish are a long-lived species (> 40 years), which initially grow rapidly on the shallow shelf areas, before undertaking an ontogenetic migration into deeper water. Although they are active predators and scavengers, there is no evidence of large-scale geographic migrations and studies using genetics, biochemistry, parasite fauna and tagging indicate a high degree of isolation between populations in the Indian Ocean, South Georgia region and the Patagonian Shelf. Patagonian toothfish spawn in deep-water (circa. 1000 m) during the austral winter, producing pelagic eggs and larvae. Larvae switch to a demersal habitat at around 100 mm (1 yr old), and inhabit relatively shallow water (< 200m) until 6-7 years of age, when they begin a gradual migration into deeper water. As juveniles in shallow water, toothfish are primarily piscivorous, consuming the most abundant, suitably sized, local prey. With increasing size and habitat depth the diet diversifies and includes more scavenging. Toothfish have weakly mineralised skeletons and a high fat content in muscle, which helps neutral buoyancy, but limits swimming capacity. Toothfish generally swim with labriform motion, but are capable of more rapid sub-carangiform swimming when startled. Toothfish were first caught as a by-catch (as juveniles) in shallow trawl fisheries but, following the development of deep-water longlining, a fishery rapidly developed throughout the Southern Ocean. The initial rapid expansion of the fishery, which led to a peak of over 40,000 tonnes in reported landings in 1995, was accompanied by problems of bird by-catch and over-exploitation as a consequence of illegal, unreported and unregulated fishing. These problems have now largely been addressed, but continued vigilance is required to ensure the species is sustainably exploited and the ecosystem effects of the fisheries are minimised.