CCAMLR

This paper is presented for the Commission’s consideration and sets out the projected outcome of the budget for 2006, a draft of the 2007 budget and an indicative forecast for the 2008 budget. The presentation is in the format determined by the Commission at its 2002 Meeting.

The Southern Ocean south of Australia is oceanographically complex, being characterized by double branches of the Sub-Antarctic Front (SAF), Polar Front (PF) and Southern Antarctic Circumpolar Current (SACCF), in addition to the Southern Boundary (SB) of the ACC. From 25 February to 3 March 2002 a 2150-km Continuous Plankton Recorder (CPR) transect was conducted along 140°E, between 47.02°S and 66.36°S, crossing each of these frontal zones. Surface temperature, salinity, and fluorescence were measured at 1-min intervals in conjunction with CPR samples. Additional physical data for the region south of 61°S was provided by nine CTD stations. Multivariate and Indicator Species analysis of the high resolution (~9.2 km) zooplankton samples identified six distinct assemblages which were strongly correlated with frontal/oceanographic zones. These assemblages appeared to be structured by a combination of zonal differences in water mass structure, phytoplankton regimes, and small scale intra-zonal features (e.g. eddies). The northern branch of the SAF was the strongest biogeographic boundary, separating a high proportion of sub-tropical and temperate species from the waters to its south. The study area differed from other sectors of the Southern Ocean in that the northern PF, equivalent to the PF in other sectors, was not a zone of distinct ecological transition. Two of the identified assemblages were located with the seasonal ice zone, south of the northern SACCF. Although Euphausia superba larvae were a component of both of these assemblages, this species, together with appendicularia, was most abundant south of the SB. The seasonal ice zone north of the SB was dominated by small copepods (Oithona similis and Ctenocalanus citer), appendicularia and foraminifera. Although the physical characteristics of the frontal zones can be subtle, the demarcation between zooplankton assemblages was clear. Cross-frontal changes in zooplankton assemblages highlight their role in long-term monitoring programs as indicators of environmental change.

A repeat transect was run south of Tasmania, along ~140°E, during November and December 2001. NORPAC nets were deployed during a CTD transect on the southern leg, sampling four depth zones at each of 19 stations: 0–20, 20–50, 50–100 and 100–150 m. A Continuous Plankton Recorder (CPR) was deployed on the northern leg (average sampling depth = 10.5 m). Both net systems were harnessed with 270 ?m mesh and all sampling was conducted between 47°S and the Southern Polar Front (S-PF) at ~61°S. Zooplankton in the top 150 m of the water column demonstrated strong, small-scale, vertical distribution patterns. Species richness and diversity increased with depth, and were lowest for CPR samples. Conversely, dominance decreased with depth and was highest for CPR samples. Evenness was similar for all sample groups, indicating that all communities had a similar distribution of abundance amongst species. There was little variation in abundance between NORPAC depth zones (average = 82 ± 47 individuals m–3), while abundance was substantially higher in the CPR samples (average = 144 ± 103 individuals m–3), despite it under-sampling fast-moving and delicate components of the plankton community. The higher CPR abundance was due to significantly higher abundance levels of Appendicularia, Oithona similis and Rhincalanus gigas nauplii. The NORPAC samples showed that these three taxa were most abundant in the surface waters. The significant increase in abundance in the CPR samples was attributed to the growth in size during the period between the NORPAC and CPR surveys (minimum 15 days) increasing their catchability. Both the NORPAC nets and CPR surveys identified distinct communities to the north and south of the Southern Sub-Antarctic Front. Owing to its shallow towing depth, the CPR focuses on species with surface distributions. Despite under-sampling some components of the zooplankton, the CPR provided sufficient taxonomic resolution to identify biogeographic zones in the Southern Ocean. The utility of the CPR as a long-term monitoring tool in the Southern Ocean is discussed.

The Continuous Plankton Recorder (CPR) Type I was first used in Antarctic waters during the 1925–1927 Discovery Expedition, and has been used successfully for 70 years to monitor plankton in the North Sea and North Atlantic Ocean. Sixty-five years later the CPR as a Type II version returned to Antarctic waters when the Australian Antarctic Division initiated a survey of the Southern Ocean on RSV Aurora Australis south of Australia and west to Mawson. The objectives are to study regional, seasonal, interannual and long-term variability in zooplankton abundance, species composition and community patterns, as well as the annual abundance and distribution of krill larvae. The survey covers a large area from 60°E to 160°E, and south from about 48°S to the Antarctic coast—an area of more than 14 million km2. Tows are conducted throughout the shipping season, normally September to April, but occasionally as early as July (midwinter). The large areal and temporal scale means that it is difficult to separate temporal and geographical variation in the data. Hence, CPRs are now also towed on the Japanese icebreaker Shirase in collaboration with the Japanese Antarctic programme. Shirase has a fixed route and time schedule, travelling south on 110°E in early December and north on 150°E in mid-March each year, and will serve as an important temporal reference for measuring long-term interannual variability and to help interpret the Australian data. Since 1991, over 90 tows have been made, providing over 36,000 nautical miles of records. The most successful seasons to date have been the 1997/1998, 1999/2000 and 2000/2001 austral summers with 20, 31 and 26 tows, respectively. The 1999/2000 season included a unique, nearly simultaneous three-ship crossing of the Southern Ocean along 25° 30’E, 110°E and 157°E. Typical CPR tows show very high abundance of zooplankton in the uppermost 20 m of the permanently open ocean zone between the sea-ice zone and the Sub-Antarctic Front; this is an area thought to be oligotrophic. Appendicularians and small calanoid and cyclopoid copepods dominate the plankton. By comparison the surface waters of the sea-ice zone have low species diversity and abundances. Zooplankton data, and hence distribution patterns, can be time- and geo-coded to GPS data and environmental data collected by the ships’ underway monitoring system (e.g. fluorescence, water temperature, salinity, and meteorological data).

Conservation of the high seas marine environment poses a significant challenge to policy-makers and managers. Marine conservation efforts are often hindered by the lack of data and the difficulties in addressing multiple, and typically conflicting uses. The majority of extant Marine Protected Areas (MPAs) are in coastal or tropical regions within national jurisdiction. Conservation of high seas MPAs has emerged on the international agenda as a critical issue requiring the application of novel approaches, international cooperation and political will. Knowledge and understanding of the marine environment and data on marine biodiversity are all typically limited for the high seas, and the use of surrogates to assist in the identification of areas of high conservation value is one possible mechanism to address and potentially overcome these limitations. Drawing upon a database spanning more than 20 years and containing approximately 140 000 records of seabird sightings at sea, this study assesses the potential use of seabirds as surrogates for marine biodiversity in the Indian sector of the Southern Ocean. At-sea ranges, species diversity and the distributions of endangered species may be appropriate selectors or filters to identify areas with high conservation values. Integrating policy with science provides an appropriate mechanism to identify and prioritise MPAs in the Southern Ocean.

South Africa is currently proclaiming a Marine Protected Area (MPA) in the Exclusive Economic Zone (EEZ) of its sub-Antarctic Prince Edward Islands. The objectives of the MPA are to: 1) contribute to a national and global representative system of MPAs, 2) serve as a scientific reference point to inform future management, 3) contribute to the recovery of the Patagonian toothfish (Dissostichus eleginoides), and 4) reduce the bird bycatch of the toothfish fishery, particularly of albatrosses and petrels. This study employs systematic conservation planning methods to delineate a MPA within the EEZ that will conserve biodiversity patterns and processes within sensible management boundaries, while minimizing conflict with the legal toothfish fishery. After collating all available distributional data on species, benthic habitats and ecosystem processes, we used C-Plan software to delineate a MPA with three management zones: four IUCN Category Ia reserves (13% of EEZ); two Conservation Zones (21% of EEZ); and three Category IV reserves (remainder of EEZ). Compromises between conservation target achievement and the area required by the MPA are apparent in the final reserve design. The proposed MPA boundaries are expected to change over time as new data become available and as impacts of climate change become more evident.