Bottlenose Dolphins in the Shannon- A Unique Visitor Attraction in Ireland
The dolphins resident in the Shannon estuary are bottlenose dolphins and they belong to a single group of marine mammals called cetaceans, which includes all whales, dolphins and porpoises of which there are thought to be over 80 different species. Cetaceans fall into either of two categories, baleen whales and toothed whales, bottlenose dolphins are in the latter group.
The bottlenose dolphin (Tursiops truncatus) occurs worldwide in tropical, sub-tropical and temperate waters and in Europe the most important concentrations appear to be of the west coast of Ireland, the population in the Shannon estuary is the only known resident group in Irish waters and is only one of six such groups in Europe.
Each year calves are born between May and August, newborn calves are easily recognisable from their small size and neo-natal folds, which line their bodies; During your trip you maybe lucky enough to observe some new born calves are observed on quite a number of trips during this period.
Size and Speed -They range in size from 1.9 m to 3.9 m and weigh up to 200 kg, they can travel at speeds of up to 40 km/hr and stay underwater for up to 20 mins, although they typically stay down for 2-3 mins.
Breeding - Female dolphins begin to have calves at 11-12 years of age and will give birth to a single calf for 20 or 30 years. The estuary is a calving ground for the dolphins and you will frequently see baby dolphins with their mothers. Young dolphins stay with their maternal group until 3-4 years of age. Feeding Bottlenose dolphins are opportunistic feeders, they will east fish, squid, crustaceans and a variety of other prey. In the estuary, the movement and abundance of salmon is thought to have a strong influence on the dolphins behaviour during the summer months. They have been observed throwing fish into the air and ringing salmon in the bays. Signs of feeding include surface rushes and irregular surfacing.
Playing - Dolphins are curious, playful, unpredictable animals, whose charming antics are bound to amaze and delight you. They are inquisitive animals that frequently approach boats and bowride. Juvenile dolphins who are much paler than adults are particularly keen to approach boats.
Commonly Used Terms
- Breaching: When a dolphin leaps into the air and falls back into the water with a splash, it is said to be breaching.
- Tail Slapping: You may observe a dolphin slapping its tail vigorously, this is thought to be a social signal or possibly a warning to the group.
- Spyhopping: When a dolphin pokes its head above the water for a look around, this is called spyhopping. Who's watching who?
- Bow-riding: Dolphins will ride the bow waves of ships and boats, being pushed along in the mass of sea a ship drives before it. They may simply be hitching a ride or doing it for thrills.
- Porpoising: at times, when traveling at speed, dolphins will leave the water each time they take a breath, it's thought to reduce friction on their bodies, which helps conserve energy. Echolocation: Dolphins transmit ultrasonic clicks into the water and then monitor and in interpret the echoes that bounce back; this enables them to build up a picture of their underwater surroundings. When hunting, they can use echolocation to determine a fish's size, shape and the direction it’s swimming.