Study to monitor Shannon estuary dolphins

Dolphins in the Shannon estuary are under surveillance following the installation of an acoustic device to monitor their movements. The study is being funded by Bord Gais as part of its environmental impact statement for a pipeline across the waterway.

The T-POD, as the device is called, looks like a canister attached to a mooring buoy. It is a spectrum analyser which incorporates a self-contained computer and hydrophone. Designed and constructed in Cornwall, England, it recognises and logs sonar clicks from cetaceans i.e whales, dolphins and porpoises.

The study is being carried out by the Shannon Dolphin and Wildlife Foundation on behalf of MC O'Sullivan, consulting engineers for the Bord Gais pipeline project. The Shannon estuary is home to the only known resident group of bottlenose dolphins in Ireland, and was recently nominated as a candidate for a marine Special Area of Conservation under the EU Habitats Directive.

Dr Simon Berrow, project manager of the foundation, said he was "very pleased" Bord Gais had taken such a responsible attitude towards the potential impact of its proposed development on the marine environment. "By determining the use of the site by dolphins, we can ensure that the development has minimal impact by advising the engineers on the best time to carry out any potentially detrimental activities, such as blasting or dredging."

The Bord Gais pipeline is part of the new Dublin to Galway and Limerick link. It aims to supply the midlands and west with natural gas and will facilitate further expansion of the natural gas network as the newly-discovered Corrib field off Co Mayo comes on stream.

Dr Berrow has expressed concern about the impact of work on the Corrib field pipeline on the cetacean population.

The T-POD is tailored for bottlenose dolphins - they use a higher frequency than porpoises - and can scan six frequency ranges for nine seconds.