SC/54/E12

 

Second annual report on IWC collaborative research in the SO GLOBEC Western Antarctic Peninsula study area

 

Deborah Thiele1, Sue Moore2, John Hildebrand3, Ari Friedlaender4, Ana Sirovic3, Rebecca Pirzl1, Mark McDonald5, Sean Wiggins3, Eileen Hofmann6, John Klinck6

 

1 Marine and Migratory Wildlife Ecology Group, School of Ecology and Environment, Deakin University, GPO Box 423,Warrnambool, Victoria, Australia 3280. 2 NOAA/National Marine Fisheries Service, National Marine Mammal Laboratory, 7600 Sand Point Way NE, Seattle, Washington 98115, USA. 3 Scripps Institution of Oceanography, University of California San Diego, CA 92093-0205, USA. 4 Duke Marine Lab., Beaufort, North Carolina, USA.  5 2535 Sky View Lane, Laramie, Wyoming 82072, USA.

6 Center for Coastal Physical Oceanography, Crittenton Hall, Old Dominion University, Norfolk, VA 23529, USA.

 

ABSTRACT

Preliminary results from the IWC collaborative studies conducted on the 2001 winter survey and the 2002 late summer mooring cruise with the US SO GLOBEC program are presented. Sea-ice cover was significantly more extensive earlier in the season in 2002. Only minke whales were observed in the study region in winter 2001, although humpback concentrations were seen as late as end of May. Concentrations of humpbacks were seen in Marguerite Bay and east of Adelaide Island up until late May in 2001; and at the ice edge in southern Marguerite Bay and the passages to the north in February 2002. Although geographic locations of concentrations of humpbacks are different between years, habitat remained consistent. Baleen whale calls detected on sonobuoys included blue, minke, and possible fin whales. Autumn and winter multidisciplinary research cruises conducted last year under this program will be repeated this year, and will include both passive acoustic and IWC visual/biopsy teams.

 

BACKGROUND

The International Whaling Commission commenced collaborative research with CCAMLR in the Southern Ocean during the1999/2000 austral summer (Reilly et al 2000 IWC/SC/52/E21, Hedley et al 2001 IWC/SC/E9). In 2001 a multi-year series of collaborative research cruises began with Southern Ocean GLOBEC. The SO GLOBEC cruises are multidisciplinary and comprise standard mooring cruises, line transect surveys over a constant grid, and process studies at selected locations, all within the Western Antarctic Peninsula study region around Marguerite Bay (Figure 1.).

 

A preliminary report on the first three cruises in this series was provided to the IWC SC in July 2001 (Thiele et al 2001SC/53/E8). A full colour copy of an updated version of SC/53/E8, and reports and images from the cruises can be found at: http://www.ccpo.odu.edu:80/Research/globec/iwc_collab/menu.html

or use the link through the IWC website under Recent Additions. For convenience, a very brief summary of SC/54/E8 can be found attached at Appendix A.

 

The current report provides a summary of research and preliminary results for the cetacean visual, biopsy and sonobuoy studies conducted on the two cruises since the last report (SC/53E8). Results from the ARP (acoustic recording package) year-long deployments are reported in Moore 2002 SC/54/O3

 

Figure 1. Survey (A) and proposed process (B) study area US SO GLOBEC Marguerite Bay, Western Antarctic Peninsula.

 

INDIVIDUAL CRUISE SUMMARIES

 

NATHANIEL B. PALMER SURVEY CRUISE

NBP 01-04 a multidisciplinary line transect cruise on the Nathaniel B. Palmer conducted as part of the US – SO GLOBEC program during winter (23 July – 1 September 2001). The line transect grid covered during this cruise is shown as part A in Figure 1.

 

Visual survey

Methods

During this cruise, observations were made from the ice tower or the bridge level of the RVIB Nathaniel B. Palmer by two observers (AF&RP).  When conditions permitted, the observer was outside along the cat-walk of the ice tower, otherwise, observations were made from inside.  Effort was focused 45° to port and starboard of the bow ahead of the vessel, while also scanning to cover the full 180° ahead of the vessel.  In ice, the method was adjusted to include searching to the beam and behind the vessel track as well, in order that cetaceans and seals hidden by ice could be detected more readily. The observers used a combination of eye and binocular (7x50 Fujinon) searching.  Effort commenced under the following conditions allowed:  daylight; winds less than 20 knots or Beaufort Sea State less than or equal to 5; visibility greater than 1 nautical mile (measured as the distance a minke whale blow could be seen with the naked eye as judged by the observers); and vessel steaming.

 

Observation effort and sightings were recorded on the laptop based Wincruz Antarctic program.  This program logs gps position, course, ship speed continuously as well as a suit of other environmental and sighting conditions described by the observers (Beaufort sea state, sighting conditions, visibility, cloud cover, ice coverage).  Visual observations were made both during the station-transect portion of the trip, as well during transit.  When possible, photographic and/or video documentation was made of each sighting for later use in individual identification, species confirmation, and habitat description.

 

Results

Generally, visual survey conditions were good during the cruise.  The combination of environmental conditions and ship activities did not result in long transit times for surveys, however, nearly 110 hours (108:35 hours total, 107:09 hours in the survey grid) of sighting effort were made during the entire cruise (Figure 2).  A total of 15 cetacean sightings of 27 animals were made on the cruise.  In Antarctic waters (south of 60°S), 11 cetacean sightings of 18 animals were made (Figure 2).  These include 9:14 minke whales, Balaenoptera acutorostrata sp., 1:1 unidentified whale, and 1:3 killer whales (Orcinus orca) (Table 1.).

Table 1. NBP 01-04 Cetacean sightings made in Antarctic waters (South of 60°S)

Species

Sightings

Animals

minke whale (Balaenoptera acutorostrata)

5

8

like minke whale

4

6

killer whale (Orcinus orca)

1

3

unidentified whale

1

1

Total

11

18

Figure 2. NBP 01-04 Cetacean visual survey effort (lines) and cetacean sightings

 

 

 

 

All of the sightings south of 60°S, except the killer whales, were from within the study area as defined by the survey grid (Figure 1).  The first cue seen for all of the sightings within the survey grid was a ‘blow’.  The entire study area was covered in pack ice ranging between 5-10/10ths coverage.  Throughout the study region ice conditions varied in percent coverage as well as thickness and ice type.  Ice conditions were recorded. Generally, ice conditions were less dense and consolidated to the west and north of the survey grid.  Ice conditions inside Marguerite Bay and to the south were generally very dense with very few leads, or areas of open water.  However, all of the sightings made in the survey area were made in 9-10/10ths ice coverage.  Whales were usually observed surfacing in small leads, less than 50 metres across, in ice areas with pressure ridges.

 

Biopsy

No biopsy sampling was attempted during the voyage.

 

Passive acoustics - sonobuoy deployments

The primary goal of this project is to determine minimum population estimates, distribution, and seasonality of mysticete whales within the west Antarctic Peninsula (WAP) region. These data will allow the rates of whale predation on krill to be modeled for the study area.  Since the calls of most baleen whales are unique and easily recognizable, it is possible to distinguish among various species using passive acoustic techniques.  Furthermore, blue whales show geographic variation in their low frequency, regularly repeated "broadcast" calls, which might prove useful in determining the origin of the stock found in the WAP region.  At the very least, it is hoped that an acoustic detection baseline can be established from which future changes in relative abundance can be measured. 

 

Methods

During the NBP01-04 cruise, sonobuoys were deployed opportunistically in order to supplement the information that will be gathered from the seafloor recorders (see SC/54/O3).  Sonobuoys are expendable underwater listening devices.  The sonobuoy has 4 main components – a float, a radio transmitter, a saltwater battery, and a hydrophone.  The hydrophone is an underwater sensor that converts the pressure waves from underwater sounds into electrical voltages that get amplified and sent up a wire (length of released wire can be set to 90, 400, or 1000 feet) to the radio transmitter that is housed in the surface float.  The radio signal is picked up by an antenna and a radio receiver on the ship, then reviewed and simultaneously recorded onto a digital audiotape.  Sonobuoys can transmit for a maximum of 8 hours before scuttling and sinking.

     

There are 2 types of sonobuoys.  Omnidirectional sonobuoys have hydrophones that can register signals up to 20 kHz, but they cannot determine the location of the sound source. DIrectional Fixing And Ranging (DiFAR) sonobuoys also have an omnidirectional hydrophone for recording sound, but it is limited to frequencies lower than 2.5 kHz.  However, DiFARs also have 2 pairs of direction sensors, which along with an internal compass can determine the exact bearing of the sound relative to the sonobuoy.  With 3 or more sonobuoys in the water it is possible to pinpoint the exact location of the sound source.  This can then be correlated to visual observations of the species of marine mammal in that location, along with behavior and grouping information. 

     

Two antennas were used during the cruise: a Yagi directional antenna and a Sinclair omnidirectional antenna. The maximum range for the radio transmission during this cruise was 17 miles on the Yagi and 12 nm on the Sinclair.  The Yagi did not prove to be a good option under heavy sea ice conditions when a lot of backing and ramming was necessary to pass through the sea ice, resulting in non-straight track line.  Also, even though the maximum range obtained on the Sinclair was 12 nm, sea ice had a big impact on sonobuoy transmission and a more typical range for a sonobuoy deployed in heavy pack ice was 4 nm.  The noise levels from the RVIB Nathaniel B. Palmer and sea ice breaking greatly affected the quality of recordings, making for a lot of very noisy data.

 

There were a couple of reasons for sonobuoy deployments.  Firstly, they provide recordings that can be compared to the seafloor data.   This will provide a calibration on content as well as detection ranges.  Secondly, they are a means of getting recordings outside of the seafloor array range. Sonobuoys were deployed when marine mammals were visually detected and randomly throughout the cruise.  A total of 54 sonobuoys were deployed: 6 omnidirectional and 48 DiFAR (12 DiFAR buoys failed, this is a fairly large proportion, but most of the failures can be attributed to the sea ice).

 

Locations of all the deployments as well as a preliminary summary of the buoys on which calls were heard can be seen in the complete (Figure 3A) and close‑up (Figure 3B) maps of the study area.  Further analysis of the recordings is needed to double check for calls that were possibly not detected during the preliminary review.  Other data noted for each deployment were: 1) the reason for the deployment, and 2) when known, sonobuoy range.  Full information on each deployed sonobuoy is given in Appendix 9 of the full cruise report, which can be found at:

http://www.ccpo.odu.edu.edu:80/Research/globec/cruises01/nbp0104_menu.html

 

Results

No baleen whales were heard on any of the deployed sonobuoys.  Seals were heard on 7 sonobuoys.  These were mostly Weddell seals, but also a crabeater and a leopard seal were heard on 1 sonobuoy each.  Most of  the calls were heard on the southern portion of the survey area (on or south of the 260 line).  A few possible killer whale calls were recorded in Paradise Harbor, after visual sighting of a group of 3 killer whales. Although 17 minke whales were visually detected during the cruise and sonobuoys were deployed whenever possible after these sightings, no minke whale calls were heard.

 

Discussion

During the last cruise (NBP 01-03 autumn 2001), correlation of cetacean distributions with concurrent hydrographic distributions show whales associated with: 1) the southern boundary of the Antarctic Circumpolar Current, 2) the frontal boundary between intrusions of warm Upper Circumpolar Deep Water and continental shelf water, and 3) the frontal boundary between inner shelf coastal current and continental shelf waters (E. Hofmann pers. Comm.).  Cetacean sightings were particularly numerous along the frontal boundary formed as the coastal current exits the southern end of Marguerite Bay. 

 

Humpback whales were associated with all three frontal boundaries while minke whales were found only along the continental shelf and coastal frontal boundaries.  The correspondence between the cetacean sightings and hydrographic features suggests that the early austral winter distribution of cetaceans along the west Antarctic Peninsula is not random, but rather is determined by the structure of the physical environment, which in turn determines prey distribution.

 

Ice coverage was much greater during the winter cruise, only minke whales (Balaenoptera acutorostrata) were sighted in the study region, and hydrographic processes measured on NBP 01-04 were also quite different from the previous cruise (J. Klinck pers comm.). Although analysis of the NBP 01-04 data is only at a preliminary stage, some comments about winter cetacean distribution relative to hydrography, sea ice concentration and structure, and prey distribution in Marguerite Bay can be made.  The northern and eastern most minke whale sightings occur along the intrusion path for oceanic water towards Marguerite Bay.  This is represented as plume features in surface salinity and ammonia, as well as subpycnocline temperature and silicate values in deep water in the Marguerite trough. The western and southernmost sightings of minke whales were made over the continental shelf break. Estimated circulation cell boundaries of water around Marguerite Bay, based on water density at 300 metres, also show a qualitative correlation to the minke whale sightings.

 

 Interestingly, the pattern of sightings of minke whales from this winter cruise in areas of dense ice cover (9-10 tenths) and where ice was observed to be pressure ridged, corresponds to the pattern of dense krill distribution under ice as reported recently in Brierley et al (2002). In their study they sampled krill distribution in open water and up to 27 km south of the ice edge and found: significantly greater densities of krill within the sea-ice than in open water; krill were concentrated within a band 1 – 13 km south of the ice edge; that krill density increased steadily as distance from ice edge and percentage of ice cover increased; and krill density declined at distances greater than 13km south of the ice edge (correlates with percentage ice cover >90%).

 

 

Figure 3.  A) Locations of sonobuoy deployment with seal and odontocete calls marked.  B) Close-up of the study area with sonobuoy deployment and call locations marked.


 

 

 

 

 

RV LAURENCE M GOULD MOORING CRUISE

LMG 02 – 01A a repeat of the previous year’s mooring cruise to retrieve and redeploy oceanographic and cetacean passive acoustic moorings on the Laurence M. Gould conducted as part of the US – SO GLOBEC program during summer (5 February – 3 March 2002).

 

Visual survey and biopsy

Methods

During this cruise, observations were made from outside, and occasionally inside, the bridge level of the LM Gould by two observers (DT&RP).  Effort was focused 45° to port and starboard of the bow ahead of the vessel, while also scanning to cover the full 180° ahead of the vessel.  In ice, the method was adjusted to include searching to the beam and behind the vessel track as well, in order that cetaceans and seals hidden by ice could be detected more readily. The observers used a combination of eye and binocular (7x50 Fujinon) searching.  Survey effort was conducted in suitable daylight conditions when the vessel was steaming.  

 

Observation effort and sightings were recorded on the laptop based Wincruz Antarctic program.  This program logs gps position, course, and ship speed continuously as well as a suit of other environmental and sighting conditions described by the observers (Beaufort sea state, sighting conditions, visibility, cloud cover, ice coverage).  Visual observations were made both during the station-transect portion of the trip, as well during transit.  When possible, photographic and/or video documentation was made of each sighting for later use in individual identification, species confirmation, and habitat description.

 

Results

Visual survey commenced off the east coast of Chile (outside the Chilean EEZ) on the southward journey to the Western Antarctic Peninsula study area. Few sightings were made until reaching the Boyd Strait and Gerlache Strait area on 10 February.  Humpback whales were numerous in this area (28 sightings/59 animals). Throughout the first mooring deployment phase of the cruise (11 – 18 February), small numbers of humpback, sei, minke, killer and unidentified whale sightings were made. After weather conditions deteriorated at B2 mooring site (Figure 4.) on 19 February, the ship headed for Porquois Pas to conduct cetacean survey in calmer waters until weather cleared in Marguerite Bay. Weather conditions were not good, and only small numbers of humpback and minkes were sighted in this area. Mooring deployments commenced in Marguerite Bay the evening of 21 February.

 

Ship time was again allocated to the IWC visual/biopsy program on the afternoon of 22 February. We took a track to the ice edge at the southern end of Marguerite Bay (Figure 6.) to investigate whale presence. Humpback whales were concentrated near the ice edge (10 sightings/30 animals) at the southern end of Marguerite Bay. Two biopsy trips were made using the zodiac, resulting in five biopsies (skin and blubber) from two groups. Plans to continue survey along this ice edge to the east were cancelled due to worsening weather the next morning.

 

The ship again headed for the protected east coast of Adelaide Island and Matha Strait. Matha Strait was reached on the morning of 24 February. A heavy ice edge here extended out into the mouth of the Straits, precluding survey. A large number of seals were evident here throughout the sea ice. The ship headed further north to Pendleton Straits and cetacean survey was conducted throughout this area. Humpback whales were concentrated in the Pendleton Strait/Mudge Passage area. Single minke whales were also sighted throughout the passage.

 

Palmer Station was reached on 26 February. Palmer Station personnel sighted two pairs of humpbacks off Cormorant Island and a zodiac trip to obtain biopsies resulted in two samples from one pair and individual photo-identification records for all four animals. Humpback whales were also numerous during the transit through Dallman Bay on 27 February (20 sightings/42 animals). Calm conditions across the Drake Passage on 28 February provided good sightings of three groups of Mesoplodon sp., hourglass dolphins and a sperm whale.

 

Total sightings for the cruise were 177 sightings : 322 animals (Table 2). The total time on effort up to 28 February was 148 hours 40 minutes. By far the most sightings were recorded in areas of high humpback whale (Megaptera novaeangliae) concentration.

 

 

 

Table 2. LMG 02-01A Cetacean sightings for entire cruise

Species

Cumulative sightings

Unidentified large whale

7/10

Hourglass dolphin

2/14

Humpback

75/168

Undetermined minke

13/18

Unidentified whale

11/62

Killer whale

1/25

Sei whale

1/8

Unidentified small whale

1/2

Unidentified cetacean

2/3

Like minke

2/2

Mesoplodont

3/13

Sperm whale

1/1

Cumulative TOTAL

117/322

 

 

 

 

Figure 4. Cruise track of LMG 02-01A with WHOI oceanographic moorings and drifters and Scripps

 

 

 

 

Figure 5. All cetacean sightings south of 60°S LMG 02-01A

 

 

Figure 6. Humpback whale (Megaptera novaeangliae) sightings LMG 02-01A

 

 

 

 

 

Passive acoustics - sonobuoy deployments

 

Methods

During the cruise, sonobuoys were deployed opportunistically to supplement the information obtained from the visual observations, as well as the ARP data (see SC/54/O3).  Sonobuoys are expendable underwater listening devices.  Four main components of a sonobuoy are a float, radio transmitter, saltwater battery, and hydrophone.  The hydrophone detects underwater sounds, which get transmitted to the underway ship using radio waves.  These sounds can be reviewed for whale calls in real-time and simultaneously recorded onto a digital audio tape (DAT).  We deployed 3 types of sonobuoys: 41B and 57B omni-directional sonobuoys that cannot determine the location of the sound source, and 53B DiFAR (Directional Fixing And Ranging) sonobuoys that can be used to determine the exact bearing of the sound from the sonobuoy.

 

Results

Sonobuoys were deployed both when marine mammals were visually detected and also randomly throughout the cruise.  A total of 39 sonobuoys was deployed – 34 omnidirectionals (19 of type 41B and 15 of type 57B) and 5 DiFARs (53B).  The locations of all the deployments are shown in Figure 5.  Species heard on the sonobuoys were blue whales (see Fig. 6 SC/54/O3 for an image of a blue whale call), minke whales, and possibly a fin whale. Sperm whales clicks, as well as unidentified beaked whale species whistles (Figure 4.) were heard on sonobuoys deployed in the Drake Passage.

 

 

Figure4.  Acoustic recording from sonobuoy deployment and sighting - Mesoplodon sp. Southern Drake Passage.

 


Figure 5. Sonobuoy deployment locations with species heard on the sonobuoy marked.  Calling whales can be heard at large distances from the sonobuoy so a detected call does not necessarily indicate vicinity of whales.

Figure 6.  Sea ice satellite image taken during LMG 02-01A (22 February 2002). Note ice covered and ice free areas.

 

Surface Temperature, Salinity, and Fluorescence Maps

For the IWC printed version of this paper, these figures have been removed to save space. The full colour version of this paper includes these figures and is available to copy from a cd at the IWC Secretariat.

 

This section presents a series of simple maps of sea surface temperature (SST), salinity (SSS), and fluorescence (Fluor) collected with the ship’s underway instrumentation. Bob Beardsley produced these for us. Two maps are shown for each variable, the first map includes the color code used to bin the variable, and the second map is more focused on Marguerite Bay.  The SST maps (Figures 7. B1, 7. B2) show the coldest water (< -1 oC) was found near the B3 mooring site (in the ice) and also just south of Palmer Station. Water near the ice edge in southern Marguerite Bay and east of Adelaide Island was generally also cold (< 0 oC).  Water in the northern Marguerite Bay and over the shelf to the west was generally warmer (0 oC < SST < 1 oC), with water off the shelf break and over the shelf north of 67o S exceeding 1 oC.

 

The freshest water (<32) was found just south of Palmer Station (Figures 7. B3, 7. B4).  In general, the water around Pourquois Pasque Island was between 32 and 32.5, with the northeast Marguerite Bay more saline with salinities between 32.5 and 33.  Surface salinities over the shelf away from the mouth of Marguerite Bay were typically above 33.  The TS plot for the surface temperature and salinity during Leg 2 (7. B5) shows the general tendency for the water above 33 to get warmer with increasing salinity.  At temperatures below about 0.5 oC, there appear to be two clusters of points, with the freshest waters having temperatures between roughly -0.5 oC  and +0.5 oC, while the coldest waters (found near the ice edge) had salinities around 33.  

 

The along-track fluorescence pattern (7. B6, 7. B7) is also complex, but it is clear that the highest relative fluorescence values (given in volts) were found within Marguerite Bay, east of Adelaide Island, and along the transit from Matha Strait deep into Pendleton Strait, while the lowest values were found over the mid- and outer shelf and along the entire track north of 65.5o S.  While the ship’s fluorometer provides a relative measure of fluorescence, the observed fluorescence pattern supports the idea that primary productivity is high in Marguerite Bay.

 

Discussion

Ice extent was very different between the two seasons. In 2001 March/early April there was virtually no ice cover in Marguerite Bay and the fjords and passages to the north. Marguerite Bay remained virtually ice free in 2001 until after the end of May. In contrast, on the 2002 mooring cruise (Feb to early March) we found both the bay and the passages to the north with significant ice cover (Figure 6.). Enough ice in many cases to prevent the ship’s passage through the passages and fjords to the north and west of Adelaide Island. A number of the mooring sites, which in 2001 were located in open water, were sea-ice covered a month earlier in 2002 (note northern extent of sea-ice in southern Marguerite Bay in Figure 6.). Sea-ice cover and the timing of ice retreat and expansion have been linked to primary productivity, krill distribution and abundance, and the timing of baleen whale migrations among other things. Last year we observed large concentrations of humpbacks in Marguerite Bay in late May, but this species was not observed in winter. It will be interesting to see whether humpback whales are still present in the M. Bay region as late this 2002 season, given the earlier expansion of sea-ice. There are visual, biopsy and sonobouy teams on the current LMG and NBP cruises (April – May 2002).

Note: An image provided to SO GLOBEC by Joe Comiso  - southern hemisphere sea ice coverage for May 23 2001 can be seen at:

http:www.ccpo.odu.edu:80/Research/globec/ice_images/menu.html

 

Marguerite Bay is well known as an area of high productivity. This year the LTER (Long Term Ecological Research) program which was conducted just prior to our cruise obtained extremely high measurements of productivity in the Marguerite Bay and surrounding areas, particularly to the west of Adelaide Island. Given the intensity and scale of the algal blooms in the region it is not surprising that we encountered whales both in the small bays and fjords throughout the WAP, in Marguerite Bay and over the shelf break. Productivity and the associated ‘downstream’ zooplankton abundance are not confined to small restricted areas in this region at this time of year. Humpback whales were observed in high concentrations at the southern ice edge in Marguerite Bay and Pendleton Strait (in the study area) and other bays and fjords to the north of Palmer Station. Feeding and social activity were observed in areas of high humpback concentration during the cruise. Minke whales were again (see SC/53/E8) sighted mainly inside the fjords. No feeding concentrations of this species were encountered this year, and all minke and minke-like sightings consisted of groups of only one or two animals. Last year on NBP 01-03 and the Polarstern voyage, humpbacks were concentrated in similar habitat (ie. Ice edge in southern Marguerite Bay and ice-free passages to the north and west of Adelaide Island). However ice edges and ice-free passages were in different geographic locations in each year, emphaisising the dynamic nature of this environment.

 

No blue whales or fin whales were observed during the visual survey, yet both these species were recorded on the sonobuoys. Blue whale calls were frequent enough (SC/54/O3) to question the effectiveness of visual surveys to detect these species.  We also plotted the IWC SM sighting data for Area I, and not a single blue whale has been sighted there over the years of those surveys. Visual surveys may be more accurate than passive acoustic techniques in detecting minke whales (as minke whales call infrequently in comparison to more vocal species like blues). Clearly though, interpretation of differences between visual and acoustic methods awaits significantly more analysis on the two data sets than is presented in this preliminary summary. The collaboration between the visual and acoustic research on these cruises has highlighted to us: the need to investigate/measure the limitations and advantages of visual and acoustic methods with some urgency; and the importance of combining both visual and acoustic techniques in cetacean surveys wherever possible.

(Note.  Jay Barlow, NMFS/SWFSC  – will be convening a workshop to consider how visual and acoustic data might be combined for quantitative assessment in late November 2002).

 

ANALYSIS AND PRESENTATION UPDATE

 

Since the Scientific Committee meeting at IWC53 presentations of the data at different stages of analysis have been made at: CCAMLR SC meeting in Hobart, Australia (October 2001); Marine Mammal Society Biennial in Vancouver, Canada (November 2001); US SO GLOBEC Planning Meeting in Washington USA (December 2001); and Ocean Science Meeting in Honolulu (February 2002).

 

In September/October 2002 a small workshop of whale, krill and oceanography people will take place in the US to assist with data integration analyses prior to the 2nd International GLOBEC Open Science Meeting in China in October and final submissions for Deep Sea Research due in November.

 

LONG TERM PLANS FOR CONTINUATION OF IWC COLLABORATION

 

Berths for IWC participation in 2002 were again provided under the Scripps NSF passive acoustic project coordinated by John Hildebrand and Sue Moore. The passive acoustic project personnel have worked in close collaboration with the IWC team throughout.

 

The current plans and proposals in development and under discussion for IWC-SO GLOBEC and IWC-CCAMLR collaborations in the future include:

BAS frontal Scotia Sea cruise  - IWC-CCAMLR and SO GLOBEC Jan-March 2003 (4 berths); and

Long term IWC participation in the continuation of successful collaborations incorporating fine scale biological oceanography surveys around feeding whales with visual/ biopsy/ passive acoustics (ARPs and sonobuoys) on US SO GLOBEC continuation (circum Antarctic – Amundsen-Bellinghausen and Ross Seas), and Australian programs (East Antarctica).

 

ACKNOWLEDGEMENTS

 

We gratefully acknowledge the support and enthusiasm of our marine science colleagues on each of the cruises; the Captains and crew of the LM Gould and N B Palmer; the Raytheon teams. This work is funded and supported by: the International Whaling Commission, National Science Foundation, Scripps Institution of Oceanography and NOAA. Thanks to Bob Beardsley for producing the temperature and salinity plots.

 

Figure 8. A minke whale just after a feast of krill in Charlotte Pass (between Marguerite Bay and Palmer Station) on the 8th Feb 2002 (Digital photo courtesy of Captain Joe, RV NB Palmer).

 

 

 

REFERENCES

Brierley, A. S., Fernandes, P. G., Brandon, M. A., Armstrong, F., Millard, N. W., McPhail, S. D., Stevenson, P., Pebody, M., Perrett, J., Squires, M., Bone, D. G., Griffiths, G. 2002. Antarctic krill under sea ice: elevated abundance in a narrow band just south of ice edge. Science 295: 1890 – 1892.

 

Hedley, S., Reilly, S., Borberg, J., Holland, R., Hewitt, R., Watkins, J., Naganobu, M., Sushin, V.  2001. Modelling whale distribution: a preliminary analysis of data collected on the CCAMLR-IWC Krill synoptic survey, 2000. Unpublished paper submitted to the International Whaling Commission Scientific Committee July 2001, London, SC/53/E9.

 

Moore, S.E. Passive acoustic detection of mysticete whales in Alaskan and Antarctic seas: a provisional summary of ongoing research and suggestions for future applications. Unpublished paper to be submitted to the International Whaling Commission Scientific Committee May 2002, London, SC/53/O3.

Reilly, S., Hedley, S., Hewitt, R., Leaper, R., Thiele, D., Pitman, R. L., Naganobu, M., Watkins, J., Holland, R. 2000. SOWER 2000: initial results from the IWC-CCAMLR program to study whales and krill in the Southern Ocean. Unpublished paper submitted to IWC SC 52.International Whaling Commission Scientific Committee June 2000, Adelaide, SC/52/E21.

 

Thiele, D., Hofmann, E., Friedlaender, A., Moore, S., McDonald, M. 2001. Preliminary report on IWC-SO GLOBEC collaborative research in the Western Antarctic Peninsula study area March – June 2001.  Unpublished paper submitted to the International Whaling Commission Scientific Committee July 2001, London, SC/53/E8.

 

Web site address for IWC cetacean summaries by cruise, cruise reports, and technical US SO GLOBEC reports:

http://www.ccpo.odu.edu:80/Research/globec/iwc_collab/menu.html or use the link through the IWC website under Recent Additions.
APPENDIX A

Summary of SC/53/E8

A preliminary report on the first three cruises in this series was provided to the IWC SC in July 2001 (Thiele et al 2001SC/53/E8). A full colour copy of an updated version of SC/53/E8, and reports and images from the cruises can be found at the IWC linked website: http://www.ccpo.odu.edu:80/Research/globec/iwc_collab/menu.html

 

The first three cruises in the ‘year round’ Southern Ocean GLOBEC series for 2001-2002 were conducted from March – June 2001. International Whaling Commission researchers participated in all three cruises (Gould LMG 01-03 USA mooring cruise, Polarstern AntXVIII5b ship and helicopter based studies Germany, Nathaniel B Palmer NBP 01-03 USA survey cruise). A combination of ship, zodiac and helicopter based visual survey, tissue biopsy, and photo identification techniques were used on the vessels by the IWC. The US passive acoustic team deployed passive acoustic moorings and expendable sonobuoys. The most frequently recorded and abundant baleen whale species in the study area were minke and humpback whales. An initial overview of oceanographic data shows strong patterns of correlation between autumn and early winter baleen whale distribution, the inshore cold Antarctic coastal current, and upwelling of this cold water produced by intrusions of the Antarctic Circumpolar Current into Marguerite Bay. Confirmation of krill autumn migration into inshore waters associated with complex bathymetry (i.e. dense aggregations in deep pools or holes) was made on these surveys. This indicates that baleen whale prey is available throughout all seasons. Baleen whales were observed in Marguerite Bay as late as June.

 

 

Figure 7. B1.  Large-scale map of SST.  The temperature is separated into 1 oC bins and plotted using the color code in the upper left.

Figure 7. B2.  Small scale map of SST.  Same color code as in B1.

 

 

 

 

Figure 7. B3.  Large scale map of SSS.  The surface salinity has been separated into 0.5 psu bins and plotted with the color code shown in the upper left.

Figure 7. B4.  Small scale SSS map. Color code is same as in B3.

Figure 7. B5.  TS diagram for the surface waters during Leg 2 (Palmer Station to Palmer Station).

Figure 7. B6.  Large scale map of surface fluorescence (in volts).  Fluorescence has been separated into 1 volt bins and plotted with the color code shown in the upper left.

Figure 7. B7.  Small scale map of surface fluorescence.  Same color code as B6.