CATT – Cetacean Acoustic Trend Tracking Project

CATT is a long term passive acoustic monitoring project utilising Chelonia F-POD acoustic loggers and Citizen Science volunteers.

This project was proposed by Chelonia Limited and the set up is outsourced to RDUK. CATT is a Research collaboration between Local Marine Conservation Groups, volunteers, Wildlife Trusts, Conservation Organisations, University of Exeter, University of Plymouth and Swansea University. In addition to tracking trends in small cetaceans we capture boat sonar, ‘Fish Intel’ Open Protocol fish tags, sediment transportation and water temperature. At the end of 2022 CATT extended from Isles of Scilly to Sussex. In 2023 we are expanding into The Channel Islands and along the Irish Sea. The data we gather is opensourced.

Current and projected CATT SITES 2023

CATT West Wales Sites
CATT South England Sites

A brief description of F-POD Data:

F-PODs continuously sample incoming sound, in the frequency range 17 – 220kHz  at 1 million samples per second and process this at a higher resolution using real-time parallel processing to select clicks that may have come from cetaceans (dolphins, porpoises and other toothed whales) and many other sources such as fish tags. A very compact summary of each click is stored in 16 bytes on an SD card.

One year of data typically occupies much less than 32GB. Automated post-processing on a PC identifies click sequences made by the animals with a much lower error rate than is currently achieved by other methods that have similar sensitivity.
The data selected is optimised as a powerful input to time-domain methods of analysing sound but this data is not what iS required for conventional noise measurements using the Fourier Transform.

CATT Channel Islands Sites
If you find any F-POD, please contact  If the F-POD has our CATT sticker, please let me know on the mobile number. 
I will trace the owners and arrange its return.

If you find any F-POD, please contact If the F-POD has our CATT sticker, please let me know on the mobile number.
I will trace the owners and arrange its return.

Marine Science - Long term acoustic Monitoring with Chelonia F-POD passive audio monitoring recorders around the U.K. coast for the CATT Project


AR buoy close

The CATT project follows a similar project ‘BlackCeTrends’ in Black Sea, and builds on experience of two highly successful projects: ‘SAMBAH’ that used the C-POD to establish the continued existence and distribution of the Baltic Sea Harbour Porpoise, and the monitoring of the catastrophic decline of the Vaquita – an endemic porpoise species in Mexico.

The main aim of CATT is to achieve long term monitoring using a flexible mixture of voluntary groups and platforms of opportunity to investigate if acoustic monitoring, a notoriously difficult field, can be made feasible for citizen scientists.

CATT objectives include, the sharing of data, training, and outreach to maximise benefits such as:

  • insights into local patterns of  cetacean activity of particular interest to participating citizen groups
  • data on cetacean activity of value to marine science and conservation.
    • opportunities for Master’s projects and larger academic studies.
    • opportunities for training in relevant skills including handling and analysing the data set.
    • opportunities for raising awareness of ocean life.

POD float 2

RDUK has experimented with a range of mooring and tracking options over the past three years. Every site needs careful consideration for safety and environmental factors.


Moorings are a big challenge. CATT is a five year minimum project so solutions must be long term, easily serviceable, within all relevant regulations and acceptable to the local fishers and communities. Some sites are taking years to bring all these things together. The safest solution is usually to share an existing proven site and use our monitoring to add value to the existing research.