CCAMLR

A compilation of US research on seabirds vulnerable to fisheries interactions.

Revisions to the current tagging protocols for tag-release and recapture of toothfish in the Ross Sea are described, including revised instructions, layout, and revisions to the data capture forms.

Research into seabird interactions with fisheries was reviewed. Only recent research (post 1990), and in relation to direct effects of fishing through fisheries mortalities was considered. The research was divided into five main groupings: a) estimation of bycatch; b) population estimation and modelling; c) foraging studies; d) molecular research; and e) management efficacy. Research on mitigation efficacy had been covered under a separate review (Bull, unpublished). The review was conducted to allow an assessment of the utility, current methodologies, and constraints of research into seabird biology and fishery interactions. Following from the findings of the review, recommendations were formulated by the review editorial panel (submitted separately to WG-FSA), to assist in the development of research plans for managing seabird mortalities and the effect of these on seabird population viability in New Zealand fisheries.

The paper documents a protocol for assessing warp strike occurrence for seabirds in trawl fisheries, and sets out the sampling plan, forms and protocols used to sample warp strikes in the southern squid fishery in 2005 in New Zealand. Results of this sampling are set out in Abraham (unpublished – also submitted to WG-FSA).

This report contains an analysis of data on seabird trawl-warp strike collected by fisheries observers. The survey was carried out in the southern squid trawl fishery (SQU6T/1T) over the summer of 2004 – 2005. The aim of the work was to test a new protocol for quantifying warp-strikes and to assess the factors (fishery, environmental, and behavioural, temporal) that appeared to influence the probability of warp strikes occurring for small and large birds. The protocol was designed for use by non-specialist observers, to provide a robust and objective assessment of warp strike occurrence. The key results are listed below.
• 904 good observations were made from 526 separate tows, on 19 different vessels
• 789 large bird heavy contacts were observed, at an average rate of 3.5 heavy contacts per hour (c. v. 9%)
• The number of small bird heavy contacts was lower, with 306 contacts over the entire survey. This corresponds to an average rate of 1.4 per hour (c. v. 12%)
• Offal discharge was the most significant factor associated with large bird strikes
• Discharging offal increased the large-bird strike rate by an estimated factor of 6, compared with no offal discharge
• The strike-rate for large-birds decreased by an estimated factor of 2 when bird bafflers were used
• Higher small-bird strikes were observed at higher discharge rates, and the small-bird strike rates were not strongly dependent on discharge type
• 106 dead or injured birds were recovered from the tows, a rate of 0.2 birds per tow (c. v. 13%)
• The discharge of offal was the factor most significantly associated with the recovery of dead and injured birds from the warps and the recovery of dead or injured birds from the warp was significantly associated with the warp strike rate

A survey of Mackerel Icefish, Champsocephalus gunnari,was undertaken in Division 58.5.2 in the vicinity of Heard Island in June 2005 to provide the information for an assessment of short-term annual yield in the 2005/2006 CCAMLR season. This paper provides a preliminary assessment of yield using the assessment methods of CCAMLR. It is proposed that a one-year projection be used in the implementation of the CCAMLR assessment method because the fish are likely to disappear after they become four years old during the coming season. This would result in an estimated yield of 1,210 tonnes, which is less than that predicted for the coming season in the 2004 assessment by WG-FSA.

The development of the National Plan of Acton for Reducing the Incidental Catch of seabirds in Chile is presented.

We carried out a pilot research program in collaboration with industry to identify techniques for future testing that are likely to reduce seabird interactions with catcher processor trawl vessels operating the Bering Sea fishery for pollock (Theragra chalcogramma) and that are practical and safe. Emphasis was placed on reducing seabird interactions with trawl cables: nets warps, as well as the netsounde cable (3rd wire). Third wire mitigation techniques included pulling the third wire as close as possible to the water at the stern with a snatch block, paired streamer lines and various deterrents attached directly to the third wire (3rd wire scarers). Warp deterrents included a boom array or a buoy placed in the offal stream forward of the warps. Results showed that both the snatch block and paired streamer lines have great potential to reduce seabird interactions with the 3rd wire, but both require refinement for practical and safe application. Deterrents applied directly on the third wire were less effective and impractical. The boom array effectively excluded birds from the area around the trawl warps. Buoys were less effective and were difficult to position effectively. Formal testing of streamer lines, the snatch block, and the warp boom on two factory trawlers retrofitted to allow for the safe and practical deployment of the seabird interaction deterrents was proposed for 2005. Limited tests suggested fish oil has great potential as a seabird deterrent.

Given the lack of information on appropriate seabird avoidance measures for small Alaskan longline vessels, we determined the “2-m access window”, or the distance astern that longline hooks were accessible to surface foraging Alaska seabirds, for 8 fishing vessels > 7.9 m to 16.8 m (> 26 to 55 feet) using two gear types: snap-on gear and fixed gear. We also determined the capability of these vessels to deploy streamer lines and/or buoy lines according to performance standard guidelines. Vessel speed was found to be a primary determinant of both the distance astern that longline hooks were accessible to surface foraging seabirds, and the performance standards of streamer lines. Vessels deploying snap-on gear at 2 to 3.5 knots produced mean access windows of 28 to 38 m while the mean access window produced by vessels deploying fixed gear at faster speeds averaged 90 m. Gear sink rates among vessels and gear types were similar (0.09 to 0.13 for snap on gear vessels and 0.07 m/s for fixed gear). We determined that the current single streamer line requirement for snap-on gear vessels over 16.8 m and with infrastructure (a 45-m streamer line with a minimum aerial distance of 20 m) was achievable and practical regardless of vessel size, especially with a lighter streamer line design. However, the current requirement for small vessels using fixed gear of a single streamer line with no mandatory material or performance standards is unlikely to provide sufficient protection to seabirds. Specific recommendations for seabird avoidance requirements are proposed for these small vessels based on these results.

In our study skeletal elements from fish species of the Antarctic waters were extracted by bioenzyme and compared with the aim to provide a computer supported identification system, including a database of bone pictures and in the near future various identification keys as well, completed by a simple tool to compare the same skeletal elements of different species. In the database most of the skeletal elements of the cranial and axial skeleton (apart from a few bones of the neurocranium) are represented by pictures, otoliths and vertebrae included. Furthermore cooperation with other institutions is needed to extend the existing work.