Looking for patterns & anomalies in the data
The F-POD.exe app has built in analysis tools that make it quick and easy to see a snapshot of animal activity
When first loading the FP3 file, we see an overview of the detection trends between June and December 2022, the height of the lines shows detction rate. Dolphin detections are in orange, and Porpoise detections are in purple.
We can see that Dolphin activity increases significantly as we enter the winter months
Porpoise activity is more consistent but summer has slightly fewer detctions
These two graphs show diel activity cycles, the 0 on the left is midnight, 12 is midday and 23 is the following midnight.
The height of each yellow line reflects the number of clicks logged in that hour, on average over the 181 day file.
The left graph shows Dolphin activity, a preference for clicking at night. The right graph shows Porpoise activity, a more even distribution
Research is underway into social communication. It is early days but we are interested in any repetitive or complex click trains.
The three above show Porpoise click trains (the click rate changes are represented by the lines in the top panel) there are some quite long clicks classified as NBHF - Narrow Band High Frequency - this will be Harbour Porpoises in U.K. waters (the purple lines in the middle panel) at a constant frequency of around 120 KHz (the blue colour in the lower panel)
On the left here is a long Dolphin click train, indicated by the orange lines in the middle panel (classified as 'other cetacean'), the multiple colours in the lower panel showing a wide bandwidth of frequencies used by Common Dolphins, and the long click train lines in the top panel. There may be hints of feeding activity or social calls here, we are gathering examples for the researchers to review.
We offer training in the use of the F-POD.exe freeware. It takes a while to become familiar with the user interface which is very cluttered.
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The files collected and donated to the CATT Project are open sourced on the Figshare+ open repository.​
Graphing is an easy way to spot anomalies, the 6 images below show averages from three sites quite close together off the Welsh coast. The top 3 images show Dolphin data, the diel patterns in yellow show a preference for night time activity, the row of graphs third down shows frequencies used by the Dolphins in their click trains. The left graph is Cardigan Bay offshore, a site with Bottlenose Dolphins, the middle graph is an inshore site with Common Dolphins and the right graph shows a nearby site off Skomer Island.
The offshore Bottlenose Dolphins (left) were clicking in a narrow band around 42 KHz, the Skomer Dolphins (right) were clicking at around 43 KHz with some activity at 120 KHz and the Inshore Common Dolphins (centre) have a big peak at 22 KHz. No idea why!
The images below show the Porpoise detections from the same files / sites over the same period. These give us confidence that the F-PODs were working normally and logging all frequencies. The frequency profiles are what we would expect from NBHF Porpoises
