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.
Google map showing geographic bounding box with values North bound -42.0 East bound 149.0 West bound 147.0 South bound -44.0
Downloads
For information on acquiring this product,
please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Product Type/Sub Type

dataset - Marine Data - Bathymetry Grid

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2011

Product Type

dataset

Topic Category

geoscientificInformation

Keywords

Marine Data
Bathymetry Grid
marine
marine survey
habitat
Marine Geoscience

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-42.0
East bound
149.0
West bound
147.0
South bound
-44.0

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).

Digital Transfer Options

onLine

DISTRIBUTION Format

xls

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

a529430e-2187-0f20-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2014-02-14

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Downloads
For information on acquiring this product,
please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).