The CCAMLR krill synoptic survey

The CCAMLR-2000 krill synoptic survey; a description of the rationale and design

P.N. Trathan, J.L. Watkins, A.W. A. Murray, A. Brierley, D. Demer, I. Everson, C. Goss, S. Hedley, R. Hewitt, S. Kawaguchi, S. Kim, M. Naganobu, T. Pauly, J. Priddle, K. Reid and P. Ward

Preamble

The aim of this document is to describe the rationale behind the CCAMLR-2000 synoptic survey and to document in one place the details underlying the survey design. Such a document will be necessary in the future, particularly during the analysis and interpretation of the survey results. Furthermore, detailed descriptions of survey design are relatively rare in the published literature, this document therefore provides an opportunity for CCAMLR to establish a lead in this topic.

At present the CCAMLR-2000 survey design and data protocols have not received final ratification by either WG-EMM, or SC-CAMLR. Therefore the status of this document should be seen as provisional; it is inevitable that it will evolve following future discussions. This document draws heavily from previous planning documents and meetings and work carried out at the Synoptic Survey Planning Meeting held in Cambridge (UK) from 8-12 March 1999. The attendees at that meeting were: A. Brierley, D. Demer, I. Everson, C. Goss, S. Hedley, R. Hewitt, S. Kawaguchi, S. Kim, A Murray, M. Naganobu, T. Pauly, J. Priddle, K. Reid, P. Trathan, P. Ward and J. Watkins (Convenor).

Introduction

Antarctic krill, Euphausia superba, are considered to be one of the key species in the Antarctic marine food web being prey to a wide variety of dependent species. In addition to consumption by natural predators, krill are also harvested commercially. Commercial exploitation of krill is managed under the direction of CCAMLR, and is regulated in accordance with a sustainable ecosystem rationale. Such management principles are still developing, however, they require fundamental knowledge about the abundance and distribution of krill.

The CCAMLR methodology for the management of krill relies heavily upon results derived from the CCAMLR generalized yield model (Constable and de la Mare, 1996) and krill yield model (Butterworth et al., 1991, 1994). This model is used to estimate the long-term annual yield of krill in Area 48 and the precautionary catch limit for the fishery (CCAMLR Conservation Measure 32/X, SC-CCAMLR-X, 1991). To run the krill yield model, a number of parameters are required, these include an estimate of the pre-exploitation biomass of krill (B0) together with an estimate of the associated variance. The current estimate of B0 used in the model is derived from the First International BIOMASS (Biological Investigation of Marine Antarctic Systems and Stocks) Experiment (FIBEX) synoptic survey which took place in January to March 1981.

Over recent years it has been increasingly recognised by the CCAMLR community that a more up to date estimate of krill biomass is required for B0 (SC-CAMLR-XII, 1993; paragraphs 2.38 to 2.43). For example, in 1996 the CCAMLR Scientific Committee recognized the urgent need for a synoptic survey in Area 48 and noted that management advice for Area 48 could not be updated until such a survey had been conducted (SC-CAMLR-XV, 1996; paragraph 4.28). Since then, plans to carry out a CCAMLR krill synoptic survey have progressed steadily (SC-CAMLR-XVI, 1997; paragraphs 5.13 to 5.19) and there is now a firm commitment to carry out a survey in the summer of 2000 (between January and February). The primary objective of this survey will be to improve the CCAMLR estimate of B0 (SC-CAMLR-XII, 1993; paragraphs 2.39 and 2.41 to 2.47); additional survey objectives have been formulated, but these are considered secondary to the estimate of B0.

The synoptic survey is a community project that will concentrate effort in Subareas 48.1, 48.2 and 48.3. The survey will involve the participation of three (or more) research vessels from different CCAMLR nations. The composition of the scientific parties aboard these vessels will also be multinational and will include relevant experts from outside the CCAMLR community. The planning effort for this multi-ship survey is considerable and complex, therefore it is crucial that all stages of the process are documented. Thus, the primary purpose of this paper is to describe in detail the procedures used to design the synoptic survey.

Sampling strategy

The synoptic survey design was a culmination of numerous decisions. These are reported in a number of separate working documents and reports and are reproduced here in order to provide a single ready source. The major design strategy decisions were:

(a) Pre-planned or adaptive transect positions

An adaptive survey design would generally offer an increased understanding of the structure of the ecosystem, and improve the coefficient of variation (CV) of the biomass estimate. However, the advantages of a more detailed description of the distribution of krill within high density areas may be out-weighed by the increased complexity in terms of survey design, execution and subsequent analysis. In the light of these concerns, a more conservative approach of utilising a pre-planned survey has been adopted as the preferred approach. Such an approach had been widely used in the past (for instance FIBEX, Anon., 1980) and is statistically robust and defensible.

(b) Systematic or random transect positions

The main objective of the survey is to improve the estimate of B0 used in the krill yield model. Although an improved estimate could be based upon a wide variety of survey designs, the chosen survey design must be statistically defensible. Modern methods of statistical analysis are continually evolving and are providing new opportunities for improved analysis. However, at present no overall consensus exists with regard to some of the model-based geostatistical methodologies. In the future, an agreed methodology using model-based methods may become available, but until that time the CCAMLR community has agreed that a randomised design coupled to a design-based analysis should produce the most statistically defensible result (CCAMLR, 1998a; 1998b Appendix 1; see also conclusions from Miller, 1994).

To achieve this the survey will follow a design based on randomized, parallel transects. The advantage of using such a design will be that it will be possible to use classical design-based statistical methods (Jolly and Hampton, 1990) without precluding model-based geostatistical methods (e.g. Petitgas, 1993; Murray, 1996) during the survey analysis. In contrast, the use of regular systematic transects would preclude the use of classical design-based statistical methods.

(c) Stratified, or unstratified design

There is still considerable uncertainty within the CCAMLR community regarding the relative abundance of krill in the open ocean compared to that over the continental shelf areas around the Antarctic Peninsular and the islands in Area 48. Although the distribution is complex (illustrated by a variety of datasets and published papers e.g. Ichii et al., 1998; Sushin and Shulgovsky, 1998), it is important that the B0 estimate is based on a survey that samples all areas where biomass is important. The FIBEX survey was based on the premise that the majority of krill biomass was close to, or over, shelf areas. However, if krill are also distributed in similar quantities in the open ocean, a design which gives a uniform density of sampling across the whole region should be used. In contrast, if krill are concentrated in particular predictable areas, an appropriate stratified sample design is likely to produce a lower overall CV. Though appropriate stratification may improve the overall CV, it will not change the expected estimate of mean biomass.

In view of the debate over the relative importance of shelf and oceanic areas, a compromise survey design was considered appropriate. Thus, the design will allocate extra effort to areas of expected krill concentration.

(d) Definition of survey boundaries

Given the complexity of the marine ecosystem (cf. Ichii et al., 1998; Sushin and Shulgovsky, 1998), natural limits to the survey area are difficult to define. In establishing appropriate boundaries a variety of factors have to be considered. These include the known historical distribution of krill, the oceanographic structure within the region, the distribution of the commercial fishery, and the distribution of the summer pack-ice. However, these ecological boundaries do not necessarily equate to the artificial limits of the Subareas that define the management boundaries.

As estimates of krill biomass may be required for strata that have been defined using either ecological or management-based criteria (for example, the Scotia Sea cf. Subarea 48.1), survey boundaries must be based on a compromise between ecological and management boundaries.

Outline of selected survey design

Considering the factors outlined in the previous section (sampling strategy) the following survey design has been agreed. The ships will undertake a series of randomised transects located within two large-scale strata that cover the Scotia Sea and the area to the north of the Antarctic Peninsular. The first of these strata will cover much of Subarea 48.3 and Subarea 48.2, whereas the second will cover most of Subarea 48.1. In order to lie orthogonal to the main axis of the regional bathymetry, the two strata will be oriented in different directions. Within these large-scale strata three regions are known to have a high abundance of krill and to be of importance to commercial fishing fleets. In these areas additional mesoscale transects will be steamed in order to reduce the CV of the biomass estimate. The first of the mesoscale strata will be to the north of South Georgia, the second will be to the north of the South Orkney Islands, and the third will be to the north of the South Shetland Islands. In the mesoscale strata, the transects will be double the transect density of the large-scale strata. The boundaries of the mesoscale strata will be coincident with the boundaries of selected large-scale sampling units in order to ensure that the survey area is uniformly covered by primary sampling units (transects) for the purposes of randomisation. Details of these cruise tracks will be found in Figures 1, 2 and 3.

Method of randomisation

Within each stratum, transects are randomised. The basic requirement for a truly randomized parallel transect survey is that all potential transect lines in the survey area should have an equal probability of being sampled. However, one problem arising from a simple randomisation procedure is that there is a possibility of transects being very close together; this can result in an inefficient use of available effort. To overcome this we have used a two-stage randomization process (see also Brierley et al., 1997). First, the survey area was divided into a series of parallel zones of equal width separated by alternating parallel inter-zones of the same width. A survey transect was then randomly placed within each of the zones. The inter-zones contain no transects and act to keep the transects a minimum distance apart. To comply with the requirement that any transect has an equal probability of being chosen, the location of the entire survey grid was then moved by a random distance equal to, or less than, the inter-zone width. Thus, using the two stage process, all sampling units have equal probability of being chosen; this gives the necessary condition for the validity of the design-based estimators.

Implementation of survey design

The computer software package used to carry out the survey design was Arc/Info Version 7.1.1 (ESRI). The final design was checked in Arc/Info and then validated using a separate software package (Proj4). The survey design was undertaken in five strata:   The implementation of the two stage randomisation process was carried out in seven steps:

(a) Generate regular 25 × 25 km base grids

Two regular 25 × 25 km grids that extended beyond the limits of the anticipated survey area were generated, one for the Scotia Sea and one for the Antarctic Peninsular. Each grid was oriented orthogonal to the general axis of the regional bathymetry. Thus, the base grid for the Scotia Sea was designed to lie parallel to the 40W meridian, whereas the grid for the Antarctic Peninsular was designed to lie at 330 to the 50W meridian; this second grid was therefore located parallel to the line between 6500.0S, 5000.0W and 6000.0S, 5546.4W. The limits of the regular base grids are shown in Table 1.

The two base grids were generated using a Lambert Conformal Conic Projection with standard parallels placed approximately 25% from the top and bottom of the anticipated survey areas; with these parallels scale errors should be approximately 1%. The parameters used for the generation of the grids are shown in Table 2.

(b) Identify the survey sampling zones and inter-zones

Following the criteria outlined above, transect sampling zones were generated on the two base grids. The zones were located at equal distances across the anticipated survey area and were separated by inter-zones of the same width. The parameters for setting up the sampling zones are shown in Table 3.

(c) Identify the random transect positions within the sampling zones

In order to assign random transect positions each sampling zone was subdivided into 125 potential positions, this gives a sampling resolution of 0.5 km for the large-scale transects and 0.25 km for the mesoscale transects. Within each sampling zone the actual transect position was determined by randomly selecting one of the potential transect positions. The random shift for each transect within each sampling zone is shown in Table 4.

(d) Identify the random grid shift

The second level of survey randomisation was carried out by subdividing the grid shift inter-zone into 125 potential grid positions, giving a sampling resolution of 0.5 km. The grid shift was chosen by picking one of these potential grid positions at random. The same grid shift was used for both base grids. This provided the second level of randomisation for both the large-scale transects and the mesoscale transects and ensured that even sampling probability was maintained. The random shifts for the grids are shown in Table 4.

(e) Identify the northern and southern limits for each transect

After randomly assigning transect positions on the X-axis of the base grid, Y-axis coordinates for the northern and southern end points of each transect were determined by extending the transects to the limits of the survey strata. The southern transect limits were identified with reference to nearby coastlines and the anticipated northern extent of the summer pack-ice, while the northern limits were identified with reference to the boundaries of Subareas 48.1, 48.2 and 48.3 (Figure 4), the existence of krill in Area 41 (Figure 5), and the frontal structure of the ACC (Figure 6).

(f) Identify waypoints along each transect

As survey transects are parallel and do not follow meridians, transect orientation continually changes. Therefore to aid navigation during the survey, waypoints were created at regular intervals along each transect. These waypoints were generated from north to south at 25 km spacing.

(g) Project the transects into geographic coordinates

The transect waypoints on the base grid were projected from the Lambert Conformal Conic Projection to geographic coordinates using the parameters shown in Table 5.

Implications for the analysis of survey strata

The different orientations of the large-scale grids leads to an overlap of some primary sampling units and a change to the sampling probability to the east of the Antarctic Peninsular. Therefore when estimating B0 for the Southwest Atlantic, it is important that an a priori selection of sampling units is made in the region of overlap. Thus, it is recommended that data collected south of 59 on transect 10 should be omitted to avoid problems in data analysis.

When preparing an estimate of B0 for the FAO Subareas, other parts of the transects outside the FAO areas will need to be omitted. For these estimates there is no ambiguity about which transect sections to discard.

Allocation of survey effort to participating vessels

Three member nations within the CCAMLR community have arranged to support the synoptic survey with approximately 30 days each of ship time. These nations are Japan, the UK and the USA. Other nations may be able to contribute effort, but at the moment they are not in a position to confirm their commitment.

The transects within the Scotia Sea (SS) and Antarctic Peninsular (AP) large-scale strata were allocated to the three vessels as follows:

Ship 1 (UK): transects SS-1, SS-4, SS-7, SS-10, AP-13, AP-16 and AP-19,
Ship 2 (USA): transects SS-2, SS-5, SS-8, AP-11, AP-14 and AP-17,
Ship 3 (Japan): transects SS-3, SS-6, SS-9, AP-12, AP-15 and AP-18.
The transects within the mesoscale strata were allocated as follows:
Ship 2 (USA): transects SGI-1, SGI-2, SGI-3 and SGI-4,
Ship 2 (USA): transects SOI-1, SOI-2, SOI-3 and SOI-4,
Ship 3 (Japan): transects SSI-1, SSI-2, SSI-3, SSI-4, SSI-5, SSI-6, SSI-7 and SSI-8.
The UK vessel (Ship 1) was not allocated any mesoscale sampling effort as it has a larger commitment to contribute effort at the large-scale.

Additional survey effort

The synoptic survey design allows for 3 survey vessels operating within a restricted period of time. However, it is possible that additional survey effort from other CCAMLR member nations will become available in the future. If this occurs, plans will be required to efficiently utilize the additional effort without compromising the validity of the basic survey design. For example, adding additional transects interleaved between existing transects would result in uneven sampling probabilities, which would be unacceptable. However, two feasible options are available, these are: Choosing between these options depends upon the amount of additional effort that becomes available. If a limited amount of effort was to become available (for example 5 or 6 days), it would be most useful if it was used to replicate one of the mesoscale strata. Conversely, if a longer period was available (for example 11 to 15 days), it would be most useful if it was used to replicate one of the large-scale strata.

It is likely that logistic constraints will dictate which strata will be sampled. However if time were unconstrained, additional effort would be used most efficiently if it were used to repeat the complete itinerary of one (or more) vessel. Following a random selection, the vessel itinerary to repeat should be that of Ship 1, followed by that of Ship 2, and then that of Ship 3.

Reduction of survey effort due to lost time

In the Southwest Atlantic it is highly likely that some survey time will be lost due to bad weather; contingency plans for lost time are therefore absolutely necessary. The following guidelines are provided in the event that weather and/or equipment failure causes serious delays. It is suggested that each vessel should check progress against the expected time at each station and make adjustments if necessary according to the following hierarchical scheme: In addition, a check should be made against the expected time at the approximate mid-point of each major transect (6 or 7 for each ship) and adjustments made according to the following hierarchical scheme:

Determination of station positions on transects

In addition to undertaking a series of acoustic transects, it was agreed that each ship should undertake a series of net hauls to collect krill and zooplankton, and a series of conductivity-temperature-depth sensor (CTD) casts to characterize water masses. The initial plans were based on the following assumptions: The major implication of such a sampling regime is that station positions are not fixed locations but rather will depend on the start time of each ship, the time and duration of the dark period and the actual progress the ship makes along each transect.

The provisional position of the stations has been determined in a series of stages:

To facilitate cruise planning we have used a PC-based spreadsheet to calculate steaming times around the survey grid. It is hoped that this spreadsheet can be made available to all cruise leaders to help monitor expected progress around the survey transects.

(a) Provisional start date for each vessel

Provisional sampling positions have been calculated assuming that the first transect to be steamed by each ship will be started at the times shown in Table 7.

(b) Times of dawn and dusk for each vessel on each transect

The times of civil twilight (where the sun is more than 6° below the horizon) are shown for each vessel respectively in Tables 8, 9 and 10. Selected positions for each transect are shown in order to provide an estimate of local conditions at different latitudes and longitudes. These set positions were selected at the northern and southern extremity of each transect and close to the middle of each transect. Three positions were considered adequate for initial planning purposes as it was recognised that station times would vary according to weather and equipment failures. The final station positions will need to be recalculated by each cruise leader as each cruise progresses.

Inspection of the twilight times for each position on each transect reveals that many parts of the survey are in areas where the sun is more than 6° below the horizon for between 4 and 6 hours. This means that the nominal 3 hours allocated for a night time station is unrealistic. Several compromises will therefore be required to ensure that the survey transects can be covered in the time available. These compromises are:

If these conditions cannot be met then the survey will take longer than originally anticipated, or the transects will have to be shortened according to the hierarchy discussed in the sampling protocols. Assuming that the compromise conditions will be met, provisional station positions have been calculated.

(c) Provisional station sampling positions

Based on the available transecting time between local civil dawn and local civil twilight, station positions were calculated. The provisional positions for each of the ships are shown in Tables 11, 12 and 13.

Regional support and context for the synoptic survey

The results derived from the CCAMLR-2000 synoptic survey will allow a new estimate of B0 to be produced. However, the magnitude of this new estimate is likely to differ from that of the existing B0 estimate derived from the FIBEX results (Trathan et al., 1992). If the difference between these two values is marked, considerable debate is likely to ensue and subsequent synoptic surveys may be required. Given the financial and logistic complexity of multi-ship operations, such future surveys cannot be relied upon.

However, the synoptic survey should be seen in the context of smaller-scale regional surveys that have been undertaken previously or which may be undertaken in the future. Of particular importance will be those smaller-scale surveys that are undertaken close to the time of the synoptic survey; especially those surveys that form part of long-term time series (such as the US AMLR survey (USA), the BAS Core Programme (UK) and the cruises fostered by the CCAMLR Sub-Group on International Coordination). If these regular regional surveys can be linked to the large-scale synoptic survey in time and space, it may be possible to interpret temporal variations observed in the regional surveys, with respect to the larger area. If this proves feasible, it may then become possible to use smaller-scale regional surveys to monitor long-term trends in krill biomass. At present, prior to the synoptic survey, any relationship between the regional surveys and the biomass across Area 48, remains undefined.

References

Anon. 1980. FIBEX Acoustic Survey Design. BIOMASS Rep. Ser., 14: 15.

Brierley, A.S., J.L. Watkins and A.W.A. Murray. 1997. Interannual variability in krill abundance at South Georgia. Mar. Ecol. Prog. Ser., 150: 87-98.

Butterworth, D.S., A.E. Punt and M. Basson. 1991. A simple approach for calculating the potential yield from biomass survey results. In: Selected Scientific Papers, 1991 (SC-CAMLR-SSP/8). CCAMLR, Hobart: 207-215.

Butterworth, D.S., G.R. Gluckman, R.B. Thomson, S. Chalis, K. Hiramatsu, and D.J. Agnew. 1994. Further computations of the consequences of setting the annual krill catch limit to a fixed fraction of the estimate of krill biomass from a survey. CCAMLR Science., 1: 81-106.

CCAMLR. 1997. Statistical Bulletin, Vol. 9, CCAMLR, Hobart, Australia.

CCAMLR. 1998a. Hydroacoustic and net krill sampling methods - Area 48 Survey. Document WG-EMM-98/24. CCAMLR, Hobart, Australia.

CCAMLR. 1998b. Report from the Steering Committee for the synoptic survey of Area 48. Document WG-EMM-98/25. CCAMLR, Hobart, Australia.

Constable, A.J. and W.K. de la Mare. 1996. A generalized model for evaluating yield and the long-term status of fish stocks under conditions of uncertainty. CCAMLR Science., 3: 31-54.

Ichii, T., K. Katayama, N. Obitsu, H. Ishii, and M. Naganobu. 1998. Occurrence of Antarctic krill (Euphausia superba) in the vicinity of the South Shetland Islands: relationships to environmental parameters. Document WG-EMM-98/18. CCAMLR, Hobart, Australia.

Jolly, G.M., and I. Hampton. 1990. A stratified random transect design for acoustic surveys of fish stocks. Can. J. Fish. Aquat. Sci., 47: 1282-1291.

Miller, D. G. M. 1994. Suggested outline for the design and implementation of future near-synoptic krill surveys. Document WG-Krill 94/20. CCAMLR, Hobart, Australia.

Murray, A.W.A. 1996. Comparison of geostatistical and random sample survey analyses of Antarctic krill acoustic data. ICES J. mar. Sci., 53: 415-421.

Orsi, A. H., T. Whitworth III, and W. D. Nowlin Jr. 1995. On the meridional extent of the Antarctic Circumpolar Current. Deep-Sea Res., 42, 641-673.

Petitgas, P. 1993. Geostatistics for fish stock assessments: a review and an acoustic application. ICES J. mar. Sci., 50: 285-298.

SC-CAMLR-X. 1991. Report of the Tenth Meeting of the Scientific Committee, CCAMLR, Hobart, Australia.

SC-CAMLR-XII. 1993. Report of the Thirteenth Meeting of the Scientific Committee, CCAMLR, Hobart, Australia.

SC-CAMLR-XV. 1996. Report of the Fifteenth Meeting of the Scientific Committee, CCAMLR, Hobart, Australia.

SC-CAMLR-XVI. 1997. Report of the Sixteenth Meeting of the Scientific Committee, CCAMLR, Hobart, Australia.

Sushin, V. A., and K. E. Shulgovsky. 1998. Krill distribution in the Western Atlantic Sector of the Southern Ocean during 1983/84, 1984/85 and 1987/88 on the basis of the Soviet mesoscale surveys with Isaacs Kidd midwater trawl. Document WG-EMM-98/32. CCAMLR, Hobart, Australia.

Trathan, P. N., D.J. Agnew, D. G. M. Miller, J. L. Watkins, I. Everson, M. R. Thorley, E. J. Murphy, A. W. A. Murray, and C. Goss. 1992. Krill biomass in Area 48 and Area 58: Recalculation of FIBEX data. In: Selected Scientific Papers, (SC-CAMLR-SSP/9), 157-182, CCAMLR, Hobart, Australia.

Trathan, P. N., M. A. Brandon, and E. J. Murphy.1997. Characterisation of the Antarctic Polar Frontal Zone to the north of South Georgia in summer 1994. J. Geophys. Res. 102: C5 10483-10497

Tables

Table 1: Limits of the 25 × 25 km base grids used as the foundation for the survey design. (Back to text)
Stratum Origin of grid Rotation of grid Northern limit Southern limit Eastern limit Western limit
Scotia Sea 62° S, 40° W 0 49° S 62° S 23° W 56° W
Antarctic Peninsular 65° S, 50° W 330 52° S 68° S 40° W 79° W

Table 2: Parameters used for the Lambert Conformal Conic Projections. (Back to text)
Stratum Spheroid Units Standard Parallel 1 Standard Parallel 2 Central Meridian Origin of Projection X,Y Shift
Scotia Sea WGS84 Metres 54°30' S 59°30' S 40° W 62° W 0, 0
Antarctic Peninsular WGS84 Metres 59°30' S 64°30' S 50° W 65° W 0, 0

Table 3: Parameters used for the determining the transect sampling zones. (Back to text)
Stratum Start position on base grid* (grid column) Width of grid shift inter-zone (km) Number of transects Width of transect sampling zone (km) Width of transect sampling inter-zone (km)
Scotia Sea 11 62.50 10 62.50 62.50
Antarctic Peninsular 15 62.50 9 62.50 62.50
South Georgia 21 62.50 4 31.25 31.25
South Orkney Islands 41 62.50 4 31.25 31.25
South Shetland Islands 25 62.50 8 31.25 31.25
* The position with row = 1, column = 1 is at the northeast corner of the grid

Table 4: Random offsets for transects within the sampling zones and for the grid shift. (Back to text)
Stratum Random shift within transect sampling zones (km) Random shift for grid (km)
T01 T02 T03 T04 T05 T06 T07 T08 T09 T10
Scotia Sea* 3.00 36.00 43.50 44.50 13.50 0.50 50.00 29.00 41.50 6.50 17.50
Antarctic Peninsular* 40.00 38.50 16.00 37.00 44.50 1.50 57.00 13.00 2.00 17.50
South Georgia+ 29.25 0.75 6.50 9.25 17.50
South Orkney Islands+ 7.75 18.25 18.50 19.25 17.50
South Shetland Islands+ 20.50 5.00 20.25 20.75 11.00 26.75 4.25 29.25 17.50
* Randomisation was carried out with potential transect sampling units separated by 0.50 km

+ Randomisation was carried out with potential transect sampling units separated by 0.25 km

Table 5: Parameters used for the Geographic Projection. (Back to text)
Stratum Spheroid Units X,Y Shift
Scotia Sea WGS84 Decimal degrees 0, 0
Antarctic Peninsular WGS84 Decimal degrees 0, 0

Table 6: Priority for omitting transects following periods of lost time; if a transect has already been surveyed, then the next highest priority transect should be omitted. (Back to text)
Vessel Priority for omission 
1 2 3 4 5 6 7 8
Ship 1 (large-scale) SS-7 AP-13 SS-10 AP-16 SS-1 SS-4 AP-19
Ship 2 (large-scale) SS-5 SS-8 AP-14 AP-11 SS-2 AP-17
Ship 3 (large-scale) AP-12 SS-3 SS-6 SS-9 AP-15 AP-18
Ship 2 (mesoscale) SGI-4 SGI-2 SGI-3 SGI-1
Ship 2 (mesoscale) SOI-2 SOI-4 SOI-1 SOI-3
Ship 3 (mesoscale) SSI-7 SSI-5 SSI-8 SSI-6 SSI-2 SSI-1 SSI-4 SSI-3

Table 7: Start times for each vessel. (Back to text)
Vessel-id Nation Start date & time
Ship 1 UK 20 Jan 2000 14:00
Ship 2 USA 14 Jan 2000 06:00
Ship 3 Japan 14 Jan 2000 11:00

Table 8: Times of civil dawn and civil dusk for each transect undertaken by Ship 1. Times are GMT. (Back to text)
Transect Position Longitude Latitude Date Civil Dawn Civil Dusk
SS01 north -31.22 -51.89 20/01/00 05:40 22:52
SS01 middle -30.13 -56.56 22/01/00 04:58 23:24
SS01 south -28.80 -61.00 24/01/00 04:08 00:06
SS04 north -37.27 -51.98 24/01/00 06:05 23:16
SS04 middle -36.93 -56.69 26/01/00 05:35 23:43
SS04 south -36.49 -61.40 27/01/00 04:46 00:32
SS07 north -42.79 -51.98 28/01/00 06:36 23:31
SS07 middle -43.16 -56.91 30/01/00 06:10 00:03
SS07 south -43.62 -61.62 31/01/00 05:29 00:48
SS10 north -48.89 -57.99 01/02/00 06:30 00:29
SS10 middle -49.54 -60.44 02/02/00 06:14 00:50
SS10 south -50.22 -62.66 03/02/00 05:55 01:15
AP13 north -56.25 -59.68 04/02/00 06:55 01:04
AP13 middle -54.45 -61.49 04/02/00 06:30 01:14
AP13 south -52.47 -63.25 05/02/00 06:05 01:23
AP16 north -62.93 -60.00 06/02/00 07:26 01:27
AP16 middle -61.52 -61.90 06/02/00 07:02 01:39
AP16 south -60.03 -63.67 07/02/00 06:40 01:50
AP19 north -69.94 -60.00 08/02/00 08:01 01:48
AP19 middle -68.38 -63.05 09/02/00 07:30 02:07
AP19 south -66.47 -66.06 10/02/00 06:47 02:35

Table 9: Times of civil dawn and civil dusk for each transect undertaken by Ship 2. Times are GMT. (Back to text)
Transect Position Longitude Latitude Date Civil Dawn Civil Dusk
SS02 north -33.53 -51.82 16/01/00 05:35 23:11
SS02 middle -32.73 -56.15 18/01/00 05:02 23:46
SS02 south -31.69 -61.20 19/01/00 03:54 00:40
SS05 north -38.63 -52.01 20/01/00 06:02 23:27
SS05 middle -38.46 -56.72 21/01/00 05:28 00:03
SS05 south -38.24 -61.43 23/01/00 04:35 00:55
SS08 north -44.59 -54.62 24/01/00 06:17 00:04
SS08 middle -45.15 -58.87 25/01/00 05:45 00:41
SS08 south -45.81 -62.89 27/01/00 04:59 01:34
AP11 north -52.74 -58.73 30/01/00 06:33 00:56
AP11 middle -51.25 -60.11 30/01/00 06:13 01:04
AP11 south -50.08 -61.11 31/01/00 06:12 00:56
AP14 north -58.81 -60.01 31/01/00 06:48 01:30
AP14 middle -57.53 -61.45 01/02/00 06:31 01:37
AP14 south -56.13 -62.88 01/02/00 06:06 01:51
AP17 north -66.33 -60.01 02/02/00 07:25 01:53
AP17 middle -64.98 -62.16 03/02/00 07:01 02:08
AP17 south -63.53 -64.17 04/02/00 06:31 02:25
SGI01 south -34.89 -54.78 15/01/00 05:16 23:40
SGI04 north -37.60 -53.11 14/01/00 05:38 23:39
SOI01 south -42.75 -60.74 28/01/00 05:24 00:44
SOI04 north -46.22 -59.73 29/01/00 05:53 00:43

Table 10: Times of civil dawn and civil dusk for each transect undertaken by Ship 3. Times are GMT. (Back to text)
Transect Position Longitude Latitude Date Civil Dawn Civil Dusk
SS03 north -35.45 -51.92 14/01/00 05:38 23:22
SS03 middle -34.88 -56.62 15/01/00 04:58 23:57
SS03 south -34.14 -61.32 17/01/00 03:52 01:01
SS06 north -40.26 -52.01 18/01/00 06:05 23:37
SS06 middle -40.29 -56.73 19/01/00 05:29 00:14
SS06 south -40.34 -61.44 21/01/00 04:34 01:11
SS09 north -46.75 -54.74 22/01/00 06:20 00:17
SS09 middle -47.52 -58.76 23/01/00 05:49 00:55
SS09 south -48.48 -62.77 24/01/00 04:55 01:57
AP12 north -54.65 -59.24 25/01/00 06:19 01:23
AP12 middle -52.34 -61.43 25/01/00 05:41 01:43
AP12 south -50.12 -63.25 26/01/00 05:03 02:04
AP15 north -61.36 -60.01 27/01/00 06:44 01:53
AP15 middle -60.03 -61.68 27/01/00 06:16 02:10
AP15 south -58.43 -63.46 28/01/00 05:44 02:30
AP18 north -67.84 -60.00 29/01/00 07:17 02:12
AP18 middle -66.33 -62.60 30/01/00 06:42 02:36
AP18 south -64.63 -65.06 31/01/00 05:51 03:13
SSI01 north -55.55 -60.50 01/02/00 06:34 01:19
SSI08 south -62.61 -62.88 05/02/00 06:51 01:59

Table 11: Provisional positions for net and CTD sampling stations for Ship 1. Times are GMT. (Back to text)
Station Station-id Transect Longitude Latitude Date & time
1  SS0101 SS01 -30.8837  -53.4453  20 Jan 23:32
2  SS0102 SS01 -30.5734  -54.7801  21 Jan 13:33
3  SS0103 SS01 -30.2413  -56.1149  21 Jan 23:12
4  SS0104 SS01 -29.8852  -57.4489  22 Jan 12:33
5  SS0105 SS01 -29.4357  -59.0032  22 Jan 23:29
6  SS0106 SS01 -28.9448  -60.5540  23 Jan 13:08
7  SS0401 SS04 -36.5109  -61.1745  24 Jan 13:29
8  SS0402 SS04 -36.6692  -59.6071  25 Jan 00:24
9  SS0403 SS04 -36.8137  -58.0372  25 Jan 14:11
10  SS0404 SS04 -36.9280  -56.6905  25 Jan 23:51
11  SS0405 SS04 -37.0344  -55.3436  26 Jan 13:23
12  SS0406 SS04 -37.1495  -53.7729  27 Jan 02:36
13  SS0407 SS04 -37.2114  -52.8761  27 Jan 14:09
14  SS0701 SS07 -42.8095  -52.2023  28 Jan 15:26
15  SS0702 SS07 -42.8866  -53.3227  28 Jan 23:49
16  SS0703 SS07 -42.9849  -54.6685  29 Jan 14:25
17  SS0704 SS07 -43.0900  -56.0152  30 Jan 00:04
18  SS0705 SS07 -43.2029  -57.3620  30 Jan 14:04
19  SS0706 SS07 -43.3242  -58.7083  30 Jan 23:43
20  SS0707 SS07 -43.4780  -60.2772  31 Jan 14:13
21  SS0708 SS07 -43.6216  -61.6195  31 Jan 23:51
22  SS1001 SS10 -49.8668  -61.5496  02 Feb 00:22
23  SS1002 SS10 -49.4155  -59.9966  02 Feb 14:19
24  SS1003 SS10 -49.0601  -58.6623  02 Feb 23:58
25  AP1301 AP13 -53.5832  -62.2921  05 Feb 00:53
26  AP1302 AP13 -55.0723  -60.8894  05 Feb 14:50
27  AP1601 AP16 -62.0074  -61.2721  07 Feb 00:54
28  AP1602 AP16 -60.8325  -62.7437  07 Feb 15:25
29  AP1603 AP16 -60.0261  -63.6703  07 Feb 23:05
30  AP1901 AP19 -66.7579  -65.6520  09 Feb 00:47
31  AP1902 AP19 -67.8720  -63.9227  09 Feb 15:20
32  AP1903 AP19 -68.6227  -62.6191  10 Feb 01:00
33  AP1904 AP19 -69.4196  -61.0931  10 Feb 15:26
34  AP1905 AP19 -69.9429  -60.0005  10 Feb 23:48

Table 12: Provisional positions for net and CTD sampling stations for Ship 2. Times are GMT. (Back to text)
Station Station-id Transect Longitude Latitude Date & time
1  SGI0301 SGI03 -36.5551  -53.9814  14 Jan 19:17
2  SGI0201 SGI02 -35.5553  -53.6031  15 Jan 04:46
3  SGI0101 SGI01 -35.0060  -53.8866  15 Jan 17:07
4  SGI0102 SGI01 -34.8924  -54.7824  16 Jan 03:35
5  SS0201 SS02 -33.4295  -52.4934  16 Jan 22:40
6  SS0202 SS02 -33.1729  -54.0565  17 Jan 13:50
7  SS0203 SS02 -32.9365  -55.3972  17 Jan 23:29
8  SS0204 SS02 -32.6393  -56.9614  18 Jan 13:58
9  SS0205 SS02 -32.3639  -58.3014  18 Jan 23:38
10  SS0206 SS02 -32.0155  -59.8625  19 Jan 13:03
11  SS0207 SS02 -31.6907  -61.1978  19 Jan 22:42
12  SS0501 SS05 -38.3117  -60.0865  21 Jan 01:15
13  SS0502 SS05 -38.3860  -58.5159  21 Jan 14:20
14  SS0503 SS05 -38.4446  -57.1683  22 Jan 00:00
15  SS0504 SS05 -38.5079  -55.5957  22 Jan 14:11
16  SS0505 SS05 -38.5581  -54.2482  22 Jan 23:51
17  SS0506 SS05 -38.6051  -52.9019  23 Jan 13:32
18  SS0801 SS08 -44.6999  -55.5132  24 Jan 23:41
19  SS0802 SS08 -44.8985  -57.0823  25 Jan 14:36
20  SS0803 SS08 -45.0826  -58.4267  26 Jan 00:16
21  SS0804 SS08 -45.3157  -59.9933  26 Jan 14:23
22  SS0805 SS08 -45.4587  -60.8873  27 Jan 00:11
23  SS0806 SS08 -45.7690  -62.6711  27 Jan 14:36
24  SOI0201 SOI02 -44.0864  -60.7096  28 Jan 20:02
25  SOI0301 SOI03 -45.0948  -59.7768  29 Jan 01:18
26  SOI0401 SOI04 -46.2158  -59.7299  29 Jan 19:29
27  SOI0402 SOI04 -46.3817  -60.6231  29 Jan 23:57
28  AP1101 AP11 -50.3436  -60.8879  30 Jan 15:40
29  AP1102 AP11 -51.6909  -59.7185  31 Jan 00:22
30  AP1103 AP11 -52.7420  -58.7345  31 Jan 11:23
31  AP1401 AP14 -58.8057  -60.0060  01 Feb 05:59
32  AP1402 AP14 -57.7186  -61.2427  01 Feb 14:41
33  AP1403 AP14 -56.3368  -62.6736  02 Feb 00:30
34  AP1701 AP17 -63.6028  -64.0762  03 Feb 00:08
35  AP1702 AP17 -65.1266  -61.9409  03 Feb 15:28
36  AP1703 AP17 -65.9425  -60.6521  04 Feb 00:10

Table 13: Provisional positions for net and CTD sampling stations for Ship 3. Times are GMT. (Back to text)
Station Station-id Transect Longitude Latitude Date & time
1  SS0301 SS03 -35.3969  -52.3671  14 Jan 13:46
2  SS0302 SS03 -35.2440  -53.7099  14 Jan 23:25
3  SS0303 SS03 -35.0806  -55.0539  15 Jan 12:52
4  SS0304 SS03 -34.8753  -56.6226  15 Jan 23:49
5  SS0305 SS03 -34.6521  -58.1907  16 Jan 13:46
6  SS0306 SS03 -34.4086  -59.7572  17 Jan 00:42
7  SS0307 SS03 -34.1419  -61.3207  17 Jan 13:11
8  SS0601 SS06 -40.3234  -60.0965  18 Jan 13:35
9  SS0602 SS06 -40.3091  -58.5255  19 Jan 00:31
10  SS0603 SS06 -40.2961  -56.9529  19 Jan 14:00
11  SS0604 SS06 -40.2858  -55.6046  19 Jan 23:40
12  SS0605 SS06 -40.2746  -54.0323  20 Jan 14:08
13  SS0606 SS06 -40.2657  -52.6859  20 Jan 23:47
14  SS0901 SS09 -46.9069  -55.6322  22 Jan 14:32
15  SS0902 SS09 -47.1562  -56.9734  23 Jan 00:12
16  SS0903 SS09 -47.4706  -58.5370  23 Jan 14:33
17  SS0904 SS09 -47.7629  -59.8754  24 Jan 00:12
18  SS0905 SS09 -48.1900  -61.6558  24 Jan 14:45
19  AP1201 AP12 -50.1248  -63.2510  25 Jan 03:32
20  AP1202 AP12 -51.6568  -62.0233  25 Jan 14:34
21  AP1203 AP12 -53.0033  -60.8403  26 Jan 00:13
22  AP1204 AP12 -54.6487  -59.2442  26 Jan 14:39
23  AP1501 AP15 -60.7156  -60.8449  27 Jan 15:03
24  AP1502 AP15 -59.6764  -62.0971  28 Jan 00:42
25  AP1801 AP18 -65.6257  -63.6743  29 Jan 15:18
26  AP1802 AP18 -66.4672  -62.3828  30 Jan 00:57
27  AP1803 AP18 -67.4827  -60.6532  30 Jan 15:20
28  SSI0201 SSI02 -56.3241  -60.6831  01 Feb 20:11
29  SSI0301 SSI03 -56.8563  -61.7915  02 Feb 08:51
30  SSI0401 SSI04 -57.9514  -62.0227  02 Feb 21:52
31  SSI0501 SSI05 -59.6069  -61.3797  03 Feb 09:54
32  SSI0601 SSI06 -60.9750  -61.6381  03 Feb 23:36
33  SSI0701 SSI07 -61.0057  -62.6053  04 Feb 11:25
34  SSI0801 SSI08 -62.6133  -62.8770  05 Feb 01:31
35  SSI0802 SSI08 -63.2521  -62.0290  05 Feb 12:59

Figures

Figure 1. CCAMLR-2000 synoptic survey cruise track for Ship 1 (UK vessel).
 

Figure 2. CCAMLR-2000 synoptic survey cruise track for Ship 2 (USA vessel).
 

Figure 3. CCAMLR-2000 synoptic survey cruise track for Ship 3 (Japanese vessel).
 

Figure 4. CCAMLR-2000 synoptic survey cruise tracks with the boundaries shown for Subarea 48.1, 48.2 and 48.3.
 

Figure 5. CCAMLR-2000 synoptic survey cruise tracks with positions where krill catches have been reported during the period 1986 to 1992 (CCAMLR, 1997).
 

Figure 6. CCAMLR-2000 synoptic survey cruise tracks with climatic positions of the major fronts in the Antarctic Circumpolar Current. SAF - Subantarctic Front; PF - Polar Front; SACCf - Southern ACC Front; SACCb - Southern ACC boundary. Positions of fronts after Orsi et al. (1995), with the Polar Front modified after Trathan et al. (1997).

 
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Page last updated on 7 July 1999