Why did animal X stop transmitting?
Gnarly - Western Australian Loggerheads - Gnaraloo Bay and Gnaraloo Cape Farquhar 2015-2016
A project of Gnaraloo Wilderness Foundation.
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Gnarly (Loggerhead) is 7 km NW off the coast of Australia and 321 km from Port Hedland
"Gnarly" was given the satellite tracker s148583 and the flipper tags WB4962 and WB4963 on 6th December 2015 after nesting at Gnaraloo Bay.
A skin biopsy sample AA55963 was taken for later DNA and Stable Isotope Analysis.
Her CCL (Curved Carapace Length)(Maximum) was 907mm; CCL(Notch) was 905mm; and CCW (Curved Carapace Width) was 793mm.
After nesting on the 6th December 2015 she immediately swam 25km north to Farquhar Bay, stayed for 3 days till the 9th December and then returned to Gnaraloo Bay. She re-nested on the 28th December and again immediately swam north to Farquhar Bay and stayed there till 10th January 2016, before returning to Gnaraloo Bay and re-nesting for the last time on the 17th January. She again immediately swam to Farquhar Bay after nesting, but this time kept going north.
Her tracker is working well on the Argos system and we have been able to follow her migration, starting when she headed north on 18th January to swim about 1000 km in 20 days, passing Exmouth on the 24th January, passing close to the northern shore of Barrow Island on the 28th January, and about 80km to sea north of Pt Headland on the 6th February. She was still heading east north-east on the 9th February 2016.
Other loggerhead studies suggest that she probably laid a total of about 360 eggs in the three known clutches at Gnaraloo Bay.
When she finally reaches her home foraging ground, the distance travelled will help inform a guess as to whether her first clutch was laid on 6th December when she was tagged, or earlier in mid-November.
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- This map connects positions generated by the ARGOS system designated as location class (lc) '3', '2', '1', '0', 'A', 'B'. Locations that have been "filtered" are displayed as small red dots.
- This maps also shows locations of class 'A' as small black dots which are not connected by a route line.
- Bathymetry layers are derived from the GEBCO One Minute Grid.
- Sea surface temperature and chlorophyll are derived from NASA's Ocean Color data.
- Ocean currents and sea surface heights are derived from AVISO's Ssalto/Duacs Gridded Absolute Dynamic Topography & absolute geostrophic velocities data.
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