Bottlenose dolphin - Deilf bholgshrónach -Dolffin trwyn potel - Tursiops truncatus 

How to identify

Thanks to the cult series ‘Flipper’, most people are familiar with bottlenose dolphins. They are large (2.50 to 3.80m long) and have a robust body. Their beak is short and thick, with a sharp crease between it and the forehead. They are dark grey with a pale underside and do not have distinct markings. Their curved dorsal fin is ½ way down their back. 


Bottlenose dolphins of Cardigan Bay in Wales – Leonie Schulz 

Ecology, social dynamics and seasonality

Bottlenose dolphins can be found in tropical and temperate, coastal and offshore waters. Ireland has a unique resident population living in the Shannon Estuary, but one other coastal and one offshore population have also been identified. Most populations have a home range within which they stay all their life rather than migrating. While coastal populations generally form small groups of 2 to 15 animals, larger groups occur in offshore populations. They feed on salmon, blue whiting, whiting, mackerel, pollock and squid and have different feeding habits depending on where they live and what they feed on. Bottlenose dolphins can be very active and frequently be seen leaping their whole body out of the water. 


Bottlenose dolphins along the Iveragh coast

While the Shannon dolphin population mostly stays within the Shannon estuary and nearby bays (Tralee and Brandon), other populations can be seen from Iveragh. Most recent land sightings have been from Portmagee, Caherdaniel and off Valentia Island, with groups of up to 22 animals. But they can also be encountered around the Skellig Islands from boats. Stranded animals have been reported as well, e.g. in Waterville. 


Bottlenose dolphins around Pen Llŷn

The south side of the Llŷn peninsula borders Cardigan Bay, which is home to a large, semi-resident, and well-studied population of Bottlenose dolphins consisting of approximately 150-200 individuals. It is possible to identify many of these individuals through photo identification by investigating the dorsal fins that usually show characteristic nicks, scratches, and shapes. Another method of identifying individuals is through recording their unique clicks and whistles. Recent research has discovered that the dolphins of Cardigan Bay have their own dialect when they communicate with each other. Their whistles have been found to be higher pitched than other populations that have been studied. So essentially, they have their own Welsh language!


The seas surrounding the peninsula are part of the Pen Llŷn a’r Sarnau SAC (special area of conservation), and bottlenose dolphins are a feature of this area. Headlands on the south side of the peninsula that offer a wide field of view are the best locations to look for bottlenose dolphins, and a calmer day always helps. The Welsh Coast Path between Abersoch and Porth Ceiriad is a good location to keep an eye out for them. A Dolphin Watch monitoring scheme was set up in Abersoch in 2016 which monitors the behaviour of leisure boats in the waters in relation to dolphins. This ensures the safety of marine mammals in the bay, as ‘Dolphin Watchers’ safeguard that observations occur from an appropriate distance and do not impact on dolphin behaviour.