Cetacean Sightings Survey and Southern Ocean Cetacean Program - data collected from the BROKE-West voyage of the Aurora Australis, 2006

Brief description

Observation on V3 commenced as the Aurora Australis departed Fremantle and concluded on the approach to Hobart.

The SOCEP research objective is to detect and document cetacean sightings and relevant environmental and other information throughout the voyage. The BROKE-West multidisciplinary voyage provides an opportunity to correlate sightings data with oceanographic and biology research conducted by other programs.

Search effort is conducted over a broad range of weather conditions. The majority of Antarctic species are medium to large whales, with cues that can be detected in relatively high Beaufort sea states up to and including Beaufort Sea State 7.

Observers search for whales while ever light, weather and sea conditions are suitable unless the vessel is stopped (e.g. CTD stations) or traveling slowly (e.g. trawling).

Data are recorded using a laptop computer-based sighting program (Wincruz for Logger v3) that automatically logs under-way data from the ship's system including GPS position, ship course and speed, wind direction and speed, and also downloads time and date when required (F1 key).

Data Collection
In the preferred and highest level of (Full Effort) two observers are positioned on the port (Port) and starboard (Starboard) sides of the flying bridge (wheelhouse roof). The search area is an arc 180 degrees ahead to abeam of the vessel, primarily with the naked eye and augmented by the use of Fujinon 7x50 binoculars.

A third observer (Tracker) is also stationed on the flying bridge. This person's role is to positively identify species, numbers and behaviour, particularly in the case of distant sightings, with the aid of Fujinon 25 x 150 binoculars (BigEyes). This team member also captures digital video footage of cetacean sightings when appropriate.

The fourth rostered team member, the Central Logger (CL) is located on the bridge and communicates with those on the flying bridge via hand-held radio transceiver. The role of the CL is to record all relevant data on the Logger laptop computer.

When in sea ice, a fifth member of the team ('Duplicate Identifier') is rostered to collect sea ice digital still images and video, and enter ice data in the SeaIce page in Logger.

The CL monitors the effort activity and progressively updates as necessary general information such as search effort, observers, weather, sea conditions.

Search effort is dropped a lower level of effort (CAS Effort), if visibility is determined to be too poor for Full Effort due to some combination of adverse weather conditions that precluded detection of most species (i.e. strong winds, fog, and large swell, confused swell, high sea state). If conditions become too poor to survey, or if the ship is traveling slowly or stopped, the effort is terminated (Off Effort). At such times the CL is generally rostered to remain on the bridge to ensure that passing whales do not go unreported, and to alert the rest of the team when the ship begins transiting at speed again or if visibility improves.

Sightings
When observers report whale sightings the CL enters the time, angle and distance from vessel, species identification, number of animals, sighting cue, behaviour and presence of ice and ancillary data. Cetaceans are identified to the lowest taxonomic level possible. Positive species identification is made only when there is certainty. Best, high and low estimates of group size are recorded for each sighting, and where more than one observer made an estimate, the final record is arrived at by consensus.

Photographic records of cetaceans (and other wildlife and habitat) are collected opportunistically using digital cameras.

Other Wildlife
Seal and penguin species are logged while in sea ice, and opportunistically elsewhere. Flying birds within 100 metres of the ship are logged half-hourly, and large flocks are logged when observed.

Other Event
Occurrences such as the sighting or marine debris are logged as they are observed.

Sea Ice Data
Sea ice observations are recorded in Logger every 10 minutes while in transit in sea ice unless the ship is stopped or transiting slowly. Sea ice data are based on observations within a 1km 90 degree radius of the ship on the port side. A buoy of known diameter is suspended just above the waterline in front of the bridge to assist with estimates of ice and snow thickness.

Sea ice still digital images are taken every 10 minutes while in transit in sea ice (unless transiting slowly), coinciding with SeaIce data recording in Logger.

Sea Ice continuous video is taken for ten minutes each half-hour, showing the bow and horizon.

The images and video assist in post cruise validation of sea ice thickness and assessment of the 1km radius for sea ice data collection. Sea ice habitat images are also captured when/where minke whales are sighted.

Acronyms

% Species 1
Percentage of group made up by Species 1

% Species 2
Percentage of group made up by Species 2

% Species 3
Percentage of group made up by Species 3

Bearing
Bearing of sighting, in degrees, relative to the ship

Beaufort
Sea state assessment using Beaufort Scale (1-12)

Berg Count
No of icebergs 180 degrees ahead

Best school size
Best estimate of the number in group

Casual observations (CAS)
Lower level of Effort e.g. fewer observers

Duplicate Identifier
Person gathering/entering ice observations/images

Dynamics
Changes to the pod's composition.

Effort Status
Classification of level of observation effort

End Time
Time sighting observation ended

Est distance
Estimated distance from ship in nm.

Floe Size
Descriptive of size/nature of ice flows

Full effort
Highest level of observation effort

Glare strength
Classification of glare as it effects visibility

Habitat Bathymetry
Determined by reference to ship's chart

High school size
Highest estimate of the number in group

Ice Conc
Concentration of ice, in tenths

Ice Thick
Ice thickness in cm

Ice Type
Descriptive nature of ice

Image File
Identification number allocated to image taken at time of data entry

In or Near Ice
Ice conditions where wildlife was sighted

Initial cue
What first drew the observer's attention to the sighting.

Left Glare
Left extremity of glare

Low school size
Lowest estimate of the number in group

Method
Whether sighting was made using naked eye, 7x50 binoculars or 25x150 (Big-eye) binoculars

Minke Vis
Estimate of the distance at which a minke whale blow could be seen in prevailing conditions

Notes
For Recorder's additional information and comments

Observer
Person reporting the sighting

Open Water
Overall ice/water situation

Port
Observer monitoring the ocean on the port side

Primary Ice Obs.
Observations of thickest ice type

Reaction
The animal's reaction to the ship

Recorder
Person entering data into Logger

Right Glare
Right extremity of glare

Secondary Ice Obs.
Observations of second-thickest ice type

Sightability
Assessment of overall viewing conditions

Sighting No
Progressive numbering of whale sightings by Logger (default)

Snow Thick
Snow thickness in cm

Snow Type
Descriptive of snow on ice

Species 1
When multiple species are being reported, with the species in greatest number listed first

Starboard
Observer monitoring the ocean on the starboard side

Swell Code
Descriptive of ocean swell

Swell Direction
Compass direction from which swell moving.

Swim direction
Animal's swim direction in degrees relative to the ship's heading

Tertiary Ice Obs
Observations of third-thickest ice type

Topog
Descriptive of ice topography e.g. ridging

Total Ice Conc
Ice concentration in tenths

Tracker
Observer using BigEyes binoculars to identify species, and assisting other observers generally

Weather Code
Weather conditions effecting visibility

An excel spreadsheet containing a full list of terms used in the observation logs is available for download from the URL given below.

This work was completed as part of ASAC projects 2253, 2655 and 2679 (ASAC_2253, ASAC_2655, ASAC_2679).