This video from Australia is called Victorian freediving part 1, clip 3. ‘This one focuses on the Australian salmon, big school passes by. ‘
From the Australian Broadcasting Corporation:
Tracking fish in southern Tasmania
Posted Wed Nov 14, 2007 2:49pm AEDT
Updated Wed Nov 14, 2007 2:48pm AEDT
Research scientists have begun placing dozens of underwater listening devices around southern Tasmania to monitor shark and fish movements.
The 72 receivers will monitor the movement of specially tagged fish in the Derwent River, Frederick Henry Bay and Norfolk Bay for at least the next 12 months.