Dugong aerial survey (dugong) Torres Strait, November 1996

Sightings for dugongs in Torres Strait area during the dugong aerials surveys in November 1996.

    Data Record Details
    Data record related to this publication Dugong aerial survey (dugong) Torres Strait, November 1996
    Data Publication title Dugong aerial survey (dugong) Torres Strait, November 1996
  • Description

    Sightings for dugongs in Torres Strait area during the dugong aerials surveys in November 1996.

  • Other Descriptors
    • Descriptor

      Funding for these surveys was obtained from the following government agencies: - Great Barrier Reef Marine Park Authority (GBRMPA), - Department of Environment and Resource Management (DERM), - Australian Marine Mammal Centre (AMMC), - Torres Strait Regional Authority (TSRA), - Australian Fisheries Management Authority (AFMA), - Marine and Tropical Sciences Research Facility (MTSRF), - National Environmental Research Program (NERP).

    • Descriptor type Note
    • Descriptor

      This dataset consists of abundance/distribution and transect maps (jpg),additional metadata (pdf) and a report (pdf).

    • Descriptor type Note
    • Descriptor

      Please contact Helene Marsh Helene.Marsh@jcu.edu.au for GIS data.

    • Descriptor type Note
    • Descriptor

      The western and central waters of Torres Strait north of 11°S were surveyed between the 10th and 13th of November 1996 using two suryey crews on two Partenavia 688 aircraft to minimise the chance of the population estimates being confounded by local movements of dugongs within the survey period. As in the 1987 and 1991 surveys, the area was divided into eight blocks on the basis of sampling intensity and transect placement. Transects were aligned in an east-west direction south of Buro (Tumagain) Island (9° 34'S, 142° 18'E), and north-south along the coast of Papua New Guinea. Transect lines were spaced 5' apart in Blocks 0, 1B, 3 and 4; and at intervals of 2.5' in Blocks 1A, 2A, 2B and 5. The survey design was determined by: (1) the boundariesof Austalian air space, (2) the known distribution of suitable dugong habitat, (3) the enduance of the aircraft from Horn Island, the only site in Austalian territory itr the region where aircraft fuel could be purchased, and (4) the aircraft time available for the survey. The design was the same as that used in the previous surveys except that: (1) of the seven eastern most transects in Block 1A, the two short transects were not flown and the remaining five were truncated at 9°10'S because we were unable to enter Papua New Guinea air space close to Daru, and (2) as in 1991, the survey intensity in Blocks 0 ard 1B was halved from that used in 1987 by increasing the interval between successive transects from 2.5' in 1987 to 5'. A total of 30,568 km² were surveyed in 1996. A global positioning system mounted in the aircraft facilitated prccise and accuste navigation. The aircmfl was frtted with a ladar altimeterfor accurateheight control. In order to increase repeatability,the survey was conducted only when the weather conditions were good (usually Beaufort sea State ≤ 3). Whenever possible, daily schedules were arranged to avoid severe glare associated with a low or midday sun. Block areas were estimated from 1:100,000 digitised topographic coverage (AUSLIG) using the ArcInfo GIS package. The areas of all islands were excluded from the block areas. The length of each transect was also estimated from these digitised maps. Survey methodology As in 1987 and 1991, we used the strip transect aerial survey methodology as detailed by Marsh and Sincair (1989a and b) andMarsh and Saalfeld(1989b) We chose to continue using this methodology rather than the line transect methods now routinely used for dolphin surveys(eg. Barlow et al. 1997) because: (1) consistent methodology is essential to a reliable time series,(2) Marsh and Saalfeld (1990) verified that the strip width used is sufficiently narrow to preclude detectable variation in dugong sightability across the transect, and (3) dugongs are generally more difficult to sight than dolphins. Dugongs are most often seen as solitary individuals or adult female-calf pairs in turbid water and exhibit cryptic surfacing behaviour.We therefore preferred to use a technique in which the observers do not have to take their eyes off the water to read an inclinometer.

    • Descriptor type Full
  • Data type dataset
  • Keywords
    • aerial survey
    • Torres Strait
    • Dugong dugon
    • ARC Centre of Excellence for Coral Reef Studies
  • Funding source
  • Research grant(s)/Scheme name(s)
  • Research themes
    Tropical Ecosystems, Conservation and Climate Change
    FoR Codes (*)
    • 050206 - Environmental Monitoring (050206)
    • 050202 - Conservation and Biodiversity (050202)
    SEO Codes
    • 960902 - Coastal and Estuarine Land Management (960902)
    Specify spatial or temporal setting of the data
    Temporal (time) coverage
  • Start Date 1996/11/10
  • End Date 2006/11/13
  • Time Period
    Spatial (location) coverage
  • Locations
    • Torres Strait, Northern Queensland, Australia.
    Data Locations

    Type Location Notes
    Physical Location Dr Alana Grech ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville QLD 4811 Australia Tel: +61 7 47815222
    Attachment Dugong aerial survey (dugong)Torres Strait, November 1996 maps and report.zip
    The Data Manager is: Alana Grech
    College or Centre
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  • Data owners
    Citation Grech, Alana; Marsh, Helene (2012): Dugong aerial survey (dugong) Torres Strait, November 1996. James Cook University.