CCAMLR

The mean mercury level for the D. eleginoides 1998 sample was 0.43 mg/kg-1, which is slightly lower than the permissible level of 0.5 mg/kg-1 set by the New Zealand Food Safety Authority (NZFSA). In contrast, mean levels of mercury for D. mawsoni were 0.10 mg/kg-1 in the 1998 samples and 0.16 mg/kg-1 in the 2006 samples, both of which are well below the permissible level.
Mercury levels were highly variable both within and between the five species studied. Once the factors length and year had been accounted for, the mercury levels in D. eleginoides were over four times greater than in D. mawsoni. The three prey species had intermediate mercury levels, with Whitson’s grenadier (Macrourus whitsoni) being only slightly lower than D. eleginoides, whilst the levels of ice fish (Chionobathyscus dewitti) and blue antimora (Antimora rostrata) were at low levels, similar to that of D. mawsoni. Mercury levels were positively correlated with fish length in four of the species. Mercury levels also showed positive trends with depth for D. eleginoides and C. dewitti, and with area for A. rostrata. Mercury levels showed no trends with any factors for M. whitsoni.
The low levels of mercury in D. mawsoni relative to its prey species and the four-fold difference in mercury concentrations between it and D. eleginoides were unexpected. Reasons for these different levels of bioaccumulation were explored including differences in diet, growth and longevity, and location. We conclude that these results can only be explained by a lower rate of mercury assimilation and/or a higher rate of mercury elimination by D. mawsoni.

This paper describes the interaction between sperm whales (Physeter macrocephalus) and the toothfish fishery (Dissostichus eleginoides) carried out by longline fishing vessels operating in two different fishing zones at 40º and 50º latitudes in the Southwestern Atlantic from March to May 2007. 62 hauls were performed in the northern zone (latitude 40º 00’ S), while 41 hauls were performed in the southern zone (latitude 50º 00’ S) at an average depth of -1282 m. 57.2% of the total number of hauls were observed. Onboard observers recorded: a) quantity and quality of fish parts remaining in the recovered longline; b) presence and number of sperm whales and c) comparative fishing yields with and without sperm whales effective predation. The observations were performed using both, the traditional Spanish longline and the Mammals and Birds Excluding Device (MBED). The longline with MBED sinking rate was determined in 1.14 m/seconds. In both fishing zones, the sperm whales presence was observed in 77.4 % of total observed sets and the effective predation was determined in 22.6 % with MBED. Effective predation was determined in 44 % of observed sets during the day period from 12:00 to 18:00 hours GMT. Lips and buccal parts were observed in 71 % of sets with traditional longline and in 27 % with MBED. The estimated fishing yields of northern and southern zones were 11.05 kg/hour and 15.53 kg/hour respectively, using the MBED and with sperm whales effective predation. In the southern zone the fishing yield increased to 23.03 kg/hour, using MBED but without sperm whale evidence of effective predation. No incidental mortality of birds was registered using both tory-line and MBED simultaneously, in spite of remarkable abundance of the southern black-browed albatross (Thalassarche melanophrys) and cape petrel (Daption capense) in 40.76 % and 23.13 % of total observed sets respectively.

Germany conducted a bottom trawl survey aboard R/V ‘Polarstern’ around Elephant Island and the South Shetland Islands from 19 December 2006 to 3 January 2007. Information on species composition, biomass, and size composition of the abundant fish species was provided. Estimates of total biomass for Elephant Island and the South Shetland Islands separately as well as biomass overall were provided for Notothenia rossii, N. coriiceps, Lepidonotothen larseni, L. squamifrons, Gobionotothen gibberifrons, Champsocephalus gunnari, Chaenocephalus aceratus and Chionodraco rastrospinosus. Biomass was found to be much lower than in 2002 and 2003 for C. gunnari, C. aceratus, C. rastrospinosus, G. gibberifrons, L. larseni and L. squamifrons while biomass was found to be higher in N. coriiceps around the South Shetland Islands and N. rossii in both areas. The proportion of juvenile G. gibberifrons, decreased further due to the production of poor year – classes since the late 1990’s. A concentration of N. rossii was found in the same location where aggregations of the species have been detected in 1975/76 and 1977/78 before they were depleted by the commercial fishery. Two concentrations of N. coriiceps were met in the South Shetland Islands. Given the low stock size of most species it is recommended to leave Elephant Island and the South Shetland Islands closed for commercial finfishing.

Pseudochaenichthys georgianus is a member of the unique Channichthyidae family, which lack haemoglobin. The distribution, length-frequency and summer diet are described from 14 bottom trawl surveys undertaken in the austral summers between 1986 and 2006. P. georgianus (50-590 mm Total Length) were caught throughout the South Georgia shelf from depths of 76 to 370 m, but very few specimens (

Since the 2001/2002 season CCAMLR has recognised the importance of the high level of hooks discarded in fish heads which ingestion by seabirds, especially wandering albatrosses which are large enough to swallow fish heads whole (SC-CAMLRR-XXI/BG/7). For example, in 2001/02 the scientific observer on the F/V Argos Helena estimated that >15,000 fish heads were discarded with hooks still in them. The hooks found in albatross colonies at South Georgia in years prior to 2001/02 were of the type used in the regulated fishery in Subarea 48.3 (SC-CAMLRR-XXI/BG/7). In 2007 overwintering scientists at Bird Island, South Georgia, have noted an increase in the occurrence of hook injuries to wandering albatrosses. The injuries appear to have two sources – injuries from the ingestion of discarded fish heads and offal, and injuries to birds that appear consistent with interactions during line hauling. This raises once again the importance of actions by CCAMLR to minimise or eliminate the discarding of fish heads containing hooks. CCAMLR–XXI noted the difficulty in getting the message to relevant fishers and indicated that alternative means should be considered. One alternative means would be the production and distribution by CCAMLR of a poster designed to educate fishers of the consequence to seabirds of discharging heads and offal containing hooks. The poster would be located in the processing areas of vessels, carry a simple and clear message, be inexpensive to produce and be produced in the languages spoken by crews. A draft poster will be submitted to WG-IMAF for discussion.

The Australian Fisheries Management Authority (AFMA) recently granted a permit for a trial of longline fishing in the Macquarie Island toothfish (Dissostichus spp.) fishery, which lies just outside the CCAMLR Area. Several threatened seabird species, including albatrosses and petrels have very small breeding populations on Macquarie Island and are potentially vulnerable to interactions with fishing vessels. The seabird bycatch mitigation measures adopted for the trial included a ban on offal discharge, night setting only, use of integrated weight longlines (CCAMLR standard); paired streamer lines and strict seabird bycatch limits.
The seabird bycatch limits categorised seabirds into three groups of species with a different limit for each group. The groupings reflected the varying conservation status of the seabird populations breeding on and foraging around Macquarie Island, and the vulnerability of each species to fisheries interactions. The group containing those species with the most critical conservation status and highest risk of interacting with fishing operations had a bycatch limit of one seabird; limits on the other categories were two and three individuals respectively. In addition, if three seabirds in total from categories 1-3 were killed as a result of interactions with fishing gear then longline fishing was to cease for the remainder of the season.

Longline fisheries worldwide have interactions that can be harmful or fatal to seabirds. We report preliminary testing of potential seabird deterrents in longline fisheries around the sub-Antarctic Kerguelen Islands. We compared White-chinned Petrel (Procellaria aequinoctialis) responses to mackerel (Scomber scombrus) baits treated with capsaicin and piperine mixtures, and untreated baits. Petrels readily consumed all untreated baits. However, there were significant differences among the six categorised responses to treated baits (capsaicin mixture: ?5 = 161.71, P

This paper summarises the historic effort and seabird bycatch mitigation measures that have applied to the Patagonian toothfish longline fishery in CCAMLR statistical division 58.5.2. It suggests that there is now sufficient experience to show that fishing under the current season timing and regime of mitigation measures poses a very low level of risk to seabirds. It proposes that the period during which fishing is allowed be extended on a trial basis to include 1 to 31 October, subject to a three seabird bycatch limit. It also proposes that the 1–30 September period be included as part of the "core" season and the 3 seabird bycatch limit no longer apply in September.

A fish biomass survey cruise, named POKER 2006, was conducted during spring 2006/07 (September-October 2006) off the Kerguelen Islands (division 58-5-1), the northern part of the Kerguelen Plateau. The sweep-area method was used in the range 100 and 1000 m with random stratified stations of bottom trawling. Estimations of biomass and abundance are provided for eight commercial species. The total biomass reaches 245 000 tonnes and the Patagonian toothfish Dissostichus eleginoides produces half of the value (124 000 tonnes). The biomass is displayed between the shelf and the deep-sea. Such evaluation is still uncompleted because four of the species (D. eleginoides, Macrourus carinatus, Bathyraja eatonii and B. irrasa) extend deeper than 1000m, the limit of the POKER 2006 survey. Some shelf and slope’ species (Champsocephalus gunnari and Notothenia rossi) exhibit low levels of biomass when compared to the previous results (1987/88, SKALP survey). Other species (Channichthys rhinoceratus and Lepidonotothen squamifrons) seem to have increased, even doubled, their biomass during the period between the two surveys. Besides the commercial species, two species were abundant: Zanclorhynchus spinifer on the shelf and Alepocephalus cf. antipodianus in the deep-sea. The data on the latest are new. The geographical and bathymetrical distributions of the species allow to conclude to a very stable localisation of the fish concentrations. Cohorts of some species (D. eleginoides, C. gunnari) were visible in some geographical sectors. In addition, the survey allows to define the species distributions, both commercial that the others, important in the ecosystem. It is of a major interest for the management and conservation of fish populations in the area.

CCAMLR Conservation Measure 25-02 requires Spanish system longline vessels attach 8.5 kg weights at 40 m intervals on longlines to minimise interactions with seabirds. The weights are collections of rocks enclosed in netting bags. The netting bags abrade on the seabed, rocks are lost and weights become progressively lighter, requiring ongoing weighing and repair. This problem can be solved by use of torpedo-shaped steel weights. Steel weights are smaller, lighter for equivalent mass, more hydrodynamic than their rocks counterparts and require no maintenance. An experiment was conducted on a chartered Spanish-rig longline vessel to determine the statistical relationship in sink rates of longlines equipped with bags of rocks (4 kg, 6 kg and 8 kg) and lines with steel weights of equivalent masses. The purpose of the experiment was to provide vessel operators with the option of substituting steel weights for rock weights while remaining in compliance to the sink rates associated with the line weighting requirements of the conservation measure. Both the traditional Spanish method and the newly-developed Chilean method (a modified version of the former method to avoid fish loss by toothed whales) were examined in the experiment. Traditional method longlines with 8 kg/40 m rock weights averaged 0.24 m/s to 2 m depth, which would be equal to or exceeded by lines with 5 kg steel weights. Sink rates of Chilean method longlines greatly exceeded those of the traditional method, ranging from 0.68 m/s (4 kg rocks) to 1.41 m/s (8 kg steel) in the shallow depth ranges. We recommend that for operational simplicity and to facilitate compliance to the conservation measure irrespective of fishing method, operators be given the option of using either 8.5 kg rock weights or 5 kg torpedo-shaped steel weights.