The CCAMLR krill synoptic survey

 

Draft plans for BAS marine biological cruises in 1999/2000

The RRS "James Clark Ross" will undertake two cruises for BAS Marine Life Sciences Division (MLSD) in the 1999/2000 field season. The first cruise
will be the fifth and final cruise of the MLSD Core Programme. The second cruise will be the UK contribution to the CCAMLR synoptic survey which is
an international multi-ship cruise taking place in January and February 2000. Both these cruises will start from and return to Stanley in the Falkland
Islands. The period between the cruises will be used for a crew change-over.

Core Programme cruise V

The BAS Core Programme was set up to study interannual variability around South Georgia, in particular variability in abundance, distribution and
population structure of Antarctic krill. The cruise consists of two major elements. The first is a standard oceanographic transect from the Maurice Ewing
Bank (north of the Antarctic Polar Front) to Bird Island (at the western end of South Georgia). The second is an acoustic survey of two 80 x 100 km
boxes located at the eastern and western ends of South Georgia.

The Maurice Ewing Bank (MEB) transect consists of 23 standard stations (spacing 35 km). At each station a CTD cast and vertical zooplankton sample
(using Bongo nets) are taken. Between the stations underway data are collected with ADCP, Simard EK500 scientific echo-sounder and suite of
measurements from the pumped 6 m non-toxic sea water supply.

After the MEB transect the ship will call at Stromness to undertake an acoustic calibration. Following calibration the eastern core box will be surveyed.
Each day a pair of 80 km transects are surveyed using ADCP, EK500 and towed UOR. These transects are arranged to take place in the hours of
daylight to avoid problems of krill migrating to near the sea surface at night. After the transects, time is available for net sampling for acoustic validation.
During the night the ship returns along the second transect of the day stopping at 2 stations to undertake a CTD cast and a RMT8 net sample. The ship is
then ready to start another acoustic transect pair the following morning. After 5 days of sampling in the eastern box the ship relocates to sample the
western core box. Therefore at the end of the survey within each box 5 pairs of acoustic transects and 4 pairs of stations will have been sampled.

Synoptic Survey cruise

This cruise is part of the CCAMLR multi-ship survey of the Scotia Sea. The main CCAMLR objective is to carry out an acoustic survey to estimate the
instantaneous standing stock of Antarctic krill (Euphausia superba) in the Scotia Sea region. In addition, the surveys will provide data on krill population
structure in the region. Thirty days have been allocated for the entire cruise which includes mobilization and demobilization in Stanley. The ship will sail
from Stanley direct to South Georgia where an acoustic calibration will be carried out in Stromness Harbour. The ship will then proceed to the start point
of the survey grid. The final survey tracks are still to be approved by the CCAMLR survey planning group but the basic plan will be as shown on the
synoptic survey web site. The survey is a randomized transect design with two levels of stratification. For the BAS cruise the more detailed second
stratum will be positioned off the north coast of South Georgia. Some of the survey tracks in this stratum will pass through the core programme survey
boxes.

The cruise will collect the core measurements proposed by CCAMLR (krill acoustics, station net hauls and CTD's). The cruise track provides an
excellent opportunity to gather information about large-scale processes across the Scotia Sea. Therefore the BAS cruise will undertake additional
measurements to estimate the krill transport rates, aspects of energetics and growth of krill, predation pressure on krill and detailed characterization of the
upper 150 m of the water column using a towed undulator.
 

Transect measurements

The following data will be collected while the ship is steaming at 10 knots along each transect:

Station measurements

The ship will carry out sampling at about 38 standard stations. The positions of these stations will essentially be decided by the location of the ship at
midday and midnight. At each station the following activities will be carried out:

Experimental activities

In addition there will be a series of experimental activities that are carried out during the cruise:

Cruise timing

The timing of both cruises is interlinked and dependent on the logistic commitments of the ship. The current time table is shown below.
 
Activity Start End
Duration (h)
CORE PROGRAMME
Mobilization Stanley 22/12/1999 09:00 24/12/1999 09:00 48 
Passage to MEB 24/12/1999 09:00 26/12/1999 21:00 60 
Morris Ewing Bank Transect 26/12/1999 21:00 31/12/1999 11:35 111 
Calibration Stromness 31/12/1999 19:35 01/01/2000 19:35 24 
Eastern Core Box 02/01/2000 03:50 06/01/2000 12:50 105 
Western Core Box 07/01/2000 03:50 11/01/2000 12:50 105 
Passage to Stanley 11/01/2000 12:50 14/01/2000 10:50 70 
Change over in Stanley 14/01/2000 10:50 17/01/2000 07:25 69 
SYNOPTIC SURVEY
Passage to Stromness 17/01/2000 07:25 20/01/2000 07:25 72 
Calibration Stromness 20/01/2000 07:25 21/01/2000 07:25 24 
Passage to start large scale survey 21/01/2000 07:25 22/01/2000 04:03 21 
Large scale survey 22/01/2000 04:03 12/02/2000 04:39 505 
Passage to King George calibration site 12/02/2000 04:47 13/02/2000 05:39 25 
Calibration King George 13/02/2000 05:39 14/02/2000 05:39 24 
Passage to Stanley 14/02/2000 05:39 16/02/2000 07:42 50 
Demobilization Stanley 16/02/2000 07:42 17/02/2000 07:42 24 
total time (days) 57

Cruise participants (synoptic survey)

Scientist-in-charge Watkins

Underway instrumentation

Station sampling

Data logging

Maintenance and support

BAS projects

International Experts

Total scientific personnel = 22 (24)


 
Introduction Itinerary Station positions Cruise tracks Planning Meeting Sampling Protocols Participants Background papers Contents

Page last updated on 5 March 1999