Often visitors to West Wales make a special visit to see the beautiful bottlenose dolphins and harbour porpoises which swim around Cardigan Bay.

Cardigan Bay was designated a Special Area of Conservation (SAC), with bottlenose dolphins listed as a primary feature for its conservation status. However there have been recent concerns about the need for a Welsh Harbour Porpoise Special Area of Conservation, because of the increased threat from man-made causes such as disturbance, habitat degradation - including pollution - and by-catch caused by fishing.   

Understanding the habitat preferences and fine-scale distribution of the two species is important for conservation management, particularly to ensure that adequate protection is provided for both populations.

Picture:  harbour porpoise needs the same protection as bottlenose dolphin, say researchers

Dr Hanna Nuuttila, scientific research officer based on the SEACAMS2* project in the College of Science at Swansea University, set about researching the abundance, distribution and habitat use of this species in Cardigan Bay.  Working with Sea Watch Foundation, a Welsh research organisation, she used acoustic monitoring techniques

The research monitored the usage of feeding sites and detected that:

• harbour porpoises were present year round in Cardigan Bay, and in greater frequency than the bottlenose dolphin.   
• There were also seasonal differences, with porpoise detections peaking in winter months and dolphin detections in summer months.
• Porpoise detections were highest at night and dolphin detections highest shortly after sunrise. 
• There are also differences in the species’ use of the area at different points in the tidal cycle.  

Statistical models were applied to the data to better understand the effects of the variants.

Commenting about her research findings, which have now been published in Marine Biology, Dr Hanna Nuuttila of Swansea University said:

“Our research findings have important implications for the design and management of protected areas. Currently, in the UK, no SACs have been formally designated for harbour porpoises while three exist for bottlenose dolphins.  The area has been identified as important for harbour porpoise and is in the process of being designated as a Special Area of Conservation (called the West Wales Marine SAC).

“Recently we have heard that following years of campaigning, by organisations such as the charity ‘Whale and Dolphin Conservation’ amongst others, proposals for English and Welsh Harbour Porpoise SACs have been submitted to the European Commission for consideration by the Welsh Government

“Hopefully these findings will aid the speedy progress of the SAC proposal at the Commission, so that future generations will still be able to enjoy the sight of  these beautiful creatures in Cardigan Bay.

“This study demonstrates there is a need for increased protection and species-specific mitigation measures to be introduced for the harbour porpoise as well as the bottlenose dolphin, if we are to protect the existence of these graceful species for many years to come.”   

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