GMR is building on theodolite research conducted as part of SouWEST, led by GMR’s Research Committee ex Chair, and conducted by Centre for Marine Science and Technology at Curtin University with its post-graduate students and volunteers). In order to understand how whales are using Geographe Bay, animals’ movements were tracked visually using a theodolite in 2011-2014.  A theodolite is traditionally a surveying instrument:  it measures angles in the horizontal and vertical planes, and is typically used to reproduce scale models of the landscape.  However, it can also be used to observe and measure the direction, distance and position of objects out at sea.

The theodolite was placed at a high vantage point overlooking the survey area: in this case, the hill behind Pt Picquet is the perfect location to look for whales travelling through Geographe Bay.  From this position, the theodolite was used to measure angles from the theodolite to a whale.  At the start of each shift, the position of the reference point was recorded (located at the slipway in Eagle Bay).  When a whale was seen, the theodolite measured the horizontal angle from the location of the theodolite to the whale, which provided information on which direction the whale was in.  The upwards or downwards tilt of the theodolite telescope gave the vertical angle – since the height of the hill the theodolite was on was known, the vertical angle could be used to calculate the distance to the whale. This work has led to numerous publications, technical reports, presentations, and a PhD thesis (see publications).

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