CCAMLR

This paper provides a review of the boundaries of the small scale research units (SSRUs) used to manage the exploratory fishery for D.mawsoni in Subarea 88.1. In determining appropriate SSRU boundaries we considered the physical and geographical features of the Subarea including the impact of sea ice on fishing practices, as well as the distribution and abundance of the target and bycatch species (rattails and skates). We recommend that the northern SSRU boundary (at 65°S) remain in place but that the other boundaries of the other four SSRUs are changed to reflect the underlying bathymetry, species distributions and ice conditions.

This report presents results from a pilot study to determine the feasibility of conducting acoustic surveys for toothfish and rattails in the Ross Sea. Acoustic data were collected during the 2002–03 exploratory fishery. Data were recorded continuously from 28 December to 2 February 2003, then during line setting only from 5–22 February 2003. Analyses were carried out to assess data quality, describe different mark types, and quantify acoustic backscatter by echo integration and echo counting. These analyses focused on the subset of acoustic data collected when setting longlines so acoustic recordings could be compared with longline catches.
Data quality was generally good. Of the 84 line recordings, 68 were considered suitable for acoustic analysis. Poor data quality was associated with strong winds and/or high seas: conditions that led to bubble interference on the hull-mounted transducer. Other issues with data quality were interference from another echosounder, and the occurrence of a double bottom echo caused by too high a ping rate.
All line recordings were in water over 1000 m deep. Because of the spreading of the acoustic beam, the acoustic deadzone at these depths is relatively large, especially if the bottom is rough or sloped. Simulations indicated that at 1500 m depth, the acoustic deadzone would be over 50 m high for a sea-bed with a slope of 20º. The problem of the acoustic deadzone was worsened by the occurrence of side-lobe echoes, produced as longlines were set on steep slopes parallel to the depth contours. Measurements indicated that side-lobe could create a deadzone of 50–100 m on apparently flat ground. Because both toothfish and rattails are considered to be demersal species, the inability of the acoustics to ‘see’ close to the bottom is a major limitation that could only be avoided with the use of a towed acoustic system.
Two types of pelagic layers were present in most acoustic recordings: a dense shallow layer between 30 and 200 m; and a more diffuse deep scattering layer between 300 and 800 m. Pelagic schools were also present in some recordings and these tended to occur at 150–400 m depth, between the layer marks. The most common demersal mark was single targets, which were present in 84% of line recordings. Most single targets occurred in a surface-referenced band between 800 and 1100 m depth, and were up to 500 m off the bottom. There was a significant positive correlation between the number of single targets counted from the echogram and the catch of rattails in the accompanying longline set. Bottom-referenced layers were present in 18% of line recordings and were also associated with higher catches of rattails. Demersal schools were present in 16% of recordings and were associated with higher catches of toothfish. Despite these associations, no acoustic marks could be reliably identified as being rattails or toothfish. It seems unlikely that the schools were toothfish or the single targets were rattails, as these were often more than 300 m off the bottom.
At this point, it is not practical to estimate toothfish or rattail abundance in the Ross Sea using hull-mounted acoustic systems. The acoustic deadzone was large, meaning it was impossible to detect demersal species close to the bottom. Echo integration was unreliable because there was a very low signal-to-noise ratio deeper than 1000 m. Echo counting showed more promise, but only relatively strong targets well separated from the bottom could be enumerated. As toothfish do not have a swimbladder, their acoustic target strength may be too weak to allow them to be counted.

Killer whale (Orcinus orca) and sperm whale (Physeter macrocephalus) interactions with longline fishing operations were recorded by CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources) observers between 2000 and 2002 at South Georgia (Subarea 48.3) in the Southeast Atlantic Ocean. Demersal longlines, targeting Patagonian toothfish (Dissostichus eleginoides), were deployed in depths of 300 to 2000m, concentrated along the 1000m contour. Sperm whales were the most abundant marine mammals observed in the vicinity of vessels when lines were being hauled, occurring during 24% of hauling observations. Killer whales, the second most sighted, occurred at 5% of haul observations. A high inter-vessel variation was noted for interactions with both species. Geographic plots of cetacean sightings during hauls were compared to fishing positions. Both killer whale and sperm whale interactions occurred over a wide geographic range and were mostly dependent on the extent of fishing effort on the different grounds, although some ‘hotspots’ for interactions seem to occur. Killer whale pods were generally small, (2 – 8 animals, 57% of observations), while solitary animals (13%) and larger pods (>15 animals, 8%) occurred less frequent. Sperm whales were most often solitary (43% of observations) when interacting with fishing vessels, although smaller groups (2 – 3) were also relatively common. Larger groups were not often sighted. Interactions with killer whales were most often observed in the day, mostly in the afternoon, while night time interactions were relatively few and usually occurred before midnight. Interactions with sperm whales followed a similar pattern occurring most often in the afternoon, while very few interactions were observed at night. Catch rates were significantly lower (P > 0.05) when killer whales were present (0.15 kg/hook; 21.5 fish/1000 hooks), when compared to hauls with no cetacean present (0.29 kg/hook; 48.5 fish/1000 hooks). The same trend was, however, not observed for catch rates when sperm whales were present during hauling (0.32 kg/hook; 51.9 fish/1000 hooks). Catch rates were in fact slightly higher in the presence of sperm whales when compared to lines with no cetacean presence. It is likely that sperm whales were attracted to areas with high catch rates, but in areas with lower catch rates indications are that depredation by sperm whales can lead to a drop-off in catches. During hook-line observations on a longliner in the 2001 season it was noted that toothfish lips on hooks were more prevalent when sperm whales were in the vicinity of the vessel, suggesting that whole fish might be ‘stripped’ off the line, leaving only the lips. This would further complicate the quantification of levels of depredation. In contrast depredation by killer whales was often characterized by the occurrence of damaged fish, with often only the heads on returning hooks, although lips were also sometimes observed when killer whales were in the vicinity. Some mitigation measures have been tried by vessels to reduce interactions with cetaceans, although no quantitative studies were done to measure their effectiveness. Further investigations are needed to determine the extent of longline-cetacean interactions, to address the problems of longlinecetacean depredation, to standardise observer protocols to ensure the collection of valuable data, and to assess and implement mitigation strategies under controlled experimental conditions.

The former fishing ground off Joinville – D’Urville Island was revisited in the course of the Antarctic Expedition ANT XIX/3 with RV ‘Polarstern’ in February 2002. Five hauls were conducted north of Joinville Island – D’Urville Island at 149 m to 282 m depth on 21 February 2002. Published and unpublished reports by the Fischkombinat in Rostock (ex- German Democratic Republic), Sea Fisheries Institute in Gdynia (Poland) and material available in YugNIRO, Kerch (Ukraine) from ex-Soviet fishing operations in the 1970’s and 1980’s were analysed in order to provide a comprehensive review of fishing activities in that area hitherto unavailable to CCAMLR.

While work to develop solutions to reduce the bycatch of seabirds and sea turtles by longline gear has begun, fishermen, managers and scientists recognize that these efforts must be enhanced and collaboration must be pursued internationally as these species are highly migratory, inhabiting the waters of many nations during their life cycle. To further this cause, the Western Pacific Fishery Regional Fishery Management Council hosted the Second International Fisheries Forum (IFF2), November 19-22, 2002, in Honolulu, Hawaii. IFF2 built on the First International Fishers Forum (IFF1) held in Auckland, New Zealand in November 2000. IFF2 widened the focus of IFF1 to address the bycatch of sea turtles as well as seabirds by longline fishing gear. More than 200 representatives from fishing industries, government agencies, non-governmental organizations and other interested parties from 28 countries in the Atlantic, East and Central Pacific, North Pacific and South Pacific participated in IFF2. The 4-day meeting opened with overview sessions on seabird and sea turtle biology, distribution, and population status assessment; longline fisheries and data collection; mitigation measures, research, and data collection; modeling; and international agreements/national approaches. Interactive breakout sessions on these various topics as well as sessions on fishermen incentives and education/communication occurred during days 2 and 3, followed by a final day of concluding exercises and the production of an IFF2 Resolution.

In the fall of 2002, the U.S. National Marine Fisheries Service (NMFS) purchased 300 copies of Beached Birds for use by North Pacific Groundfish Observers deployed on commercial fishing vessels in the Bering Sea and Gulf of Alaska. This new guide replaces a dichotomous key on looseleaf paper with black and white drawings. The purpose of using this new educational tool is to enhance the ability of fishery observers to accurately identify seabirds as they come up in the sampled fishing gear, typically wet and bedraggled birds---appearances much different than living specimens. A description of Beached Birds is provided as well as how this guide has been incorporated into observer training and data collection at the NMFS North Pacific Groundfish Observer Program. A copy of Beached Birds is available in the CCAMLR Library.

The streamer line has become the primary seabird mitigation device prescribed and used in most longline fisheries throughout the world, based to a large degree on the precedent set by CCAMLR in 1991. This discussion paper responds to the interest of the IMAF working group to consider possible revisions to the CCAMLR streamer line requirement. Existing literature on the effectiveness of single and paired (or multiple) streamer lines is reviewed and CCAMLR streamer line performance and material standards are discussed and contrasted with recent Alaskan requirements.

This is a follow-up paper to WG-EMM-03/05. Suggestions on the applicability of the use of shags for monitoring fish populations are presented, providing potential answers to the questions posed by WG-EMM in its 2003 meeting.

Worldwide, the incidental capture or bycatch of marine organisms, especially mammals, turtles and seabirds, can pose serious threats to specific animal populations causing public outcry and regulatory attention. When such issues arise, especially in US fisheries, they can threaten fisheries and necessitate immediate solutions. Unfortunately, no standard mechanisms exist within stewardship and regulatory authorities to go beyond problem identification to crafting solutions. We have worked to devise solutions to seabird mortality in two fisheries: the Puget Sound drift gillnet fishery for sockeye salmon and the longline fisheries in Alaska for sablefish and Pacific cod. Although these fisheries are very different, the cooperative research model we have developed is the same and is proving successful in both. At the most basic level, this model includes communication and cooperation with all stakeholders, strict scientific protocols and development of effective and practical regulations. Although this model was developed with specific reference to seabird bycatch reductions, it is readily applicable to a wide range of conservation issues. There are three key elements: 1) Working with industry leaders through relevant industry associations to identify possible new technologies and/or operational practices that are practical and likely to solve the problem; 2) Testing the proposed solutions in a collaborative study on active fishing vessels using strict scientific protocols, and developing incentives for individual participants to: a) host scientists, who collect the necessary data, and b) adhere to a specific scientific protocol within their standard operation is key; 3) Crafting new regulations based on the results of the research program in cooperation with the industry, resource management agencies and conservation organizations. Our model results in proof at two levels. At the practical level, fisher’s ideas are tested in the context of an active fishery. At the scientific level, peer review and publication certify results for the regulatory, academic, and conservation communities.