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CERF Underwater video and stills from SE Tasmania

Note: This metadata describes the dataset in accordance with the ANZLIC (Australia New Zealand Land Information Council) Core Metadata Guidelines Version 2.


Dataset citation

ANZLIC unique identifier: ANZCW0703015195

Title: CERF Underwater video and stills from SE Tasmania


Custodian

Custodian: Geoscience Australia

Jurisdiction: Australia


Description

Abstract:

Geoscience Australia carried out marine surveys in south-east Tasmania in 2008 and 2009 (GA0315) to map seabed bathymetry and characterise benthic environments through observation of habitats using underwater towed video. Data was acquired using the Tasmania Aquaculture and Fisheries Institute (TAFI) Research Vessel Challenger. Bathymetric mapping was undertaken in seven survey areas, including: Freycinet Pensinula (83 sq km, east coast and shelf); Tasman Peninsula (117 sq km, east coast and shelf); Port Arthur and adjacent open coast (17 sq km); The Friars (41 sq km, south of Bruny Island); lower Huon River estuary (39 sq km); D Entrecastreaux Channel (7 sq km, at Tinderbox north of Bruny Island), and; Maria Island (3 sq km, western side). Video characterisations of the seabed concentrated on areas of bedrock reef and adjacent seabed in all mapped areas, except for D Entrecastreaux Channel and Maria Island. The GA0315_SETasi folder contains video footage; the excel file is the video characterisation data. Underwater video footage represents raw data. Video characterisation dataset include percent cover of substate.

ANZLIC search words:

  • GEOSCIENCES Mapping
  • MARINE

Spatial domain:

locality map

Geographic extent name: AUSTRALIA EXCLUDING EXTERNAL TERRITORIES - AUS - Australia - Australia

Geographic extent polygon: 144 -40, 149 -40, 149 -44, 144 -44, 144 -40,

Note: The format for each Geographic extent name is: Name - Identifier - Category - Jurisdiction (as appropriate) See GEN Register

Geographic bounding box:
North bounding latitude: -40 °
South bounding latitude: -44 °
East bounding longitude: 149 °
West bounding longitude: 144 °

Data currency

Beginning date: 2009-02-23

Ending date: 2009-02-23


Dataset status

Progress: Complete

Maintenance and update frequency: Not Known


Access

Stored data format:
DIGITAL - xls Microsoft Excel spreadsheet Excel
Available format type:
DIGITAL - xls Microsoft Excel spreadsheet Excel

Access constraints:

This material is released under the Creative Commons Attribution 3.0 Australia Licence.

Free Data Download

Data quality

Lineage:

A total of 55 video transects were surveyed from five study areas (Tasman Peninsula, Freycinet Peninsula, The Friars, Huon river, and Port Arthur channel) in water depths ranging from 15-110 m using Geoscience Australias shallow-water Raytech towed-video system. The towed-camera system housed a forward-facing video camera and associated lights, and was deployed from the stern of the RV Challenger and towed at 0.5 to 1.5 knots. A small electro-hydraulic winch was used to maintain the video system at an altitude of 0.5 - 2 m above the seabed, while a coaxial cable transmitted video footage to the ships video monitor where it was characterised in real-time by the observer and similtaneously recorded to mini DV tapes, which were later copied to digital format. To characterise along-shore and off-shore habitat transitions in each survey area, primary transects were allocated perpendicular to the shoreline and secondary transects (e.g. Fortescue region) were run parallel to shore, intersecting primary transects. Primary transects traversed the greatest depth gradient, and were initiated as close to shore or islands as was safely navigable (approximate 20-30 m water depth on the RV Challenger), and extended out beyond the deepest reefs to characterise both the reef-sediment interface and the adjacent shelf habitat. In areas of deep reefs, transects were run across and beyond each reef (e.g. Roxys Reef). Seabed habitats and biota were characterised in real-time using C-BED (Characterisation of the Benthos and Ecological Diversity) the 3-tiered characterisation scheme of Anderson et al. (2008) that records substratum composition, bedform-relief, and presence of macro- biota. C-BED characterisations were recorded in real-time at 30 second intervals along each transect, or more frequently across transition zones. At each 30-second location, the seabed was evaluated for a period of 15-seconds (i.e. 5 seconds prior to and 10 seconds following the GPS fix) to characterise the seabed. Substrata composition (i.e. rock, boulders (greater than 25.5cm), cobbles (6.5-25.5 cm), gravel, sand and mud) was categorised by primary (greater than 50% cover) and secondary (greater than 20% cover) percent-cover following the protocol of Stein et al. (1992) and Yoklavich et al. (2000).

Positional accuracy:

video characterisations are recorded with a 1 m spatial accuracy, and therefore fully co-located with the multibeam data layers. The precise location of the towed-video system was tracked using a USBL (Ultra-short Baseline). USBL navigation (UTC date, time, latitude, and longitude) was captured for each data-entry and logged continuously (1-2 second fixes) to provide navigational tracks for all video transects, with a visual date/time stamp recorded onto the video image.

Attribute accuracy:

Substrata and relief variables are recorded following a clear set of definitions following the protocol of Anderson et al., (2008). Substrata composition (i.e. rock, boulders (greater than 25.5cm), cobbles (6.5-25.5 cm), sand, and mud) was categorised by primary (greater than 50% cover) and secondary (greater than 20% cover) percent-cover following the earlier protocol of Stein et al. (1992) and Yoklavich et al (2000). Bedform-relief was defined as either soft-sediment bedform such as hummocky, sediment ripples, or sediment waves, or by the vertical relief of consolidated sediments: relief classes ranged from flat (0 m), low (less than 1 m), moderate (1-3 m), to high relief (greater than 3 m), or rock walls (high-relief with greater than 80 degree incline). Some inconsistencies in seabed characterisations may occur due to the need for multiple observers (Dr Drs. Tara Anderson, Neville Barrett, and Mr Matthew McArthur - Leg1; and Mr Matthew McArthur and Dr Nicole Hill - Leg2), however, an overlap in observers (Mr Matthew McArthur - both Legs) was intigated to reduce inconsistencies. A preliminary QA/QC (15% of the dataset randomly checked by Dr Tara Anderson), identified that Leg1 of the survey was fit for purpose (less than 5% data errors), but that there was greater than 20% error rate of some taxa (%cover of screw shells, some invertebrates from Freycinet Peninsula) from Leg2. A full data check of all records has not been undertaken. Attribute definitions can be found in definitions.xls

Logical Consistency:

All model outputs data have been visually checked for artefacts and spurious data. Tests

conducted to ensure data are reliable and valid.

Completeness:

Complete


Contact information

Contact organisation: Commonwealth of Australia (Geoscience Australia) (GA)
Contact position: Manager Client Services
Mail address: Cnr Jerrabomberra Ave and Hindmarsh Dr
Mail address: GPO Box 378
Locality: Canberra
State: ACT
Country: Australia
Postcode: 2601
Telephone: 02 6249 9966
Facsimile: 02 6249 9960
Electronic mail address: sales@ga.gov.au

Metadata information

Metadata date: 2013-03-08


Additional metadata

Metadata reference XHTML: http://www.ga.gov.au/meta/ANZCW0703015195.html

Metadata reference XML: http://www.ga.gov.au/meta/ANZCW0703015195.xml

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Authors:Geoscience Australia
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