The T-POD (www.chelonia.co.uk) is a self-contained, submersible hydrophone and computer which recognises and logs the high-frequency clicks made by dolphins. These "echolocation" clicks are used by dolphins (and porpoises) to explore their environment, find prey and communicate.
This screenshot from the programme TPOD.exe shows a 4-second period in the early morning of June 30th. These clicks were recorded in the frequency range between 90 and 130 kHz, indicating that they are clicks from Heaviside's dolphins. Time is shown on the x-axis and the y-axis shows Pulse Repetition Frequency, or click rate. The red and yellow lines probably represent clicks from at least 2 dolphins, since one series of clicks appears to be increasing in speed, whilst another series (the yellow and red line on the bottom right of the screen) is slower.
This is the first use of T-PODs to acoustically monitor Heaviside's dolphins! Watch this space for developments and more detailed findings......
Many thanks to Dr Simon Northridge at the University of St. Andrews for the loan of this equipment.