CCAMLR

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.

We describe a new fishing technique, called the Chilean system, adapted from an artisan fishery for Patagonian Toothfish. The artisan system was modified to include a net sleeve that is placed on secondary vertical lines, which has practically eliminated depredation by killer whales and sperm whales. In addition to this, each 15 m-long vertical line carry a weight at the end, this sinks baited hooks at up to 0.80 m/sec. This fast sink rate causes the line to sink immediately behind the vessel preventing seabirds from seeing the baited hooks at the surface. Additionally, this system does not reduce CPUE when compared to the traditional Spanish longline system. We evaluate the performance of this fishing technique with regard to seabird mortality and depredation of sperm whales and killer whales on fish catch rate during the season September-December 2006 in the fishery of the Drake Passage in Chilean waters.

Line setters are used with integrated weight (50 g/m lead core, IW) by some autoline vessels in the Kerguelen and Crozet Islands Patagonian toothfish fisheries to deter seabirds, ostensibly by expediting gear sink rates. A trial was conducted in the Ross Sea in 2007 to determine the effectiveness of line setters in increasing sink rates of IW longlines. Time-depth recorders were deployed along magazines of line set with and without a line setter using a paired treatment design. Sink rates of longlines set with and without a line setter were identical, including in the first few metres of the water column where seabird interactions are likely to be most intense. The results reveal that line setters confer no sink rate advantage to IW longlines. Longlines deployed with a line setter enter the water several metres closer to the stern of vessels, thereby increasing slightly (

Mackerel icefish (Champsocephalus gunnari) has been exploited since the early 1970’s and became the target species of fisheries in many parts of the low-Antarctic from 1975 to 1990. Exploitation has been limited to South Georgia and Heard and McDonald Islands since the second half of the 1990’s with annual catches of a few thousand tonnes in each of the two areas. Aspect of the biology and exploitation of the species have been summarized in Kock and Everson (2003) and Kock (2005). Additional information is scattered over various CCAMLR working papers of the last 15 years. The species profile collates existing information on the taxonomy and biology of the species.

Scientific observation was conducted in the commercial trip on the ling-liner «Simeiz», operating under the Ukrainian flag, in the south-western Atlantic Ocean outside the exclusive (marine) economic zones of the foreign states (FAO statistical area 41) in the period from November, 7, 2006 till April, 2, 2007. Fisheries for Patagonian toothfish were carried out on two fishery grounds: “Scotia” bank (subarea 41.3.2) and Patagonian shelf (subarea 41.3.1) between 47 and 42° S. Most catches did not exceed 500 kg per a long-line set. Substantial differences were noted neither in size composition nor in the biological state of fishes both in different operating periods and on different fishery grounds.

Information on CCAMLR fisheries of relevance to the work of WG-FSA is summarised, including availability of data, data-related developments in 2006/07, validation of CASAL files, catches in assessed and exploratory fisheries, and updates to WG-FSA’s Fishery Reports. Additional fishery-related information can be found in WG-FSA-07/6, 07/7, 07/8 and 07/9 (summaries of observer data), SC-CAMLR-XXVI/BG/1 (catches in the Convention Area) CCAMLR-XXVI/12 (summary of notification for new and exploratory fisheries), WG-FSA-07/10 (estimates of IUU catches) and CCAMLR-XXVI/BG/17 (implementation of fishery-related conservation measures).