Dolphins, whales and porpoises all belong to a group of marine mammals known as cetaceans. These all have streamlined bodies and extremely strong tails for efficient propulsion through the water. They breathe air (like other mammals) through a blow hole in the top of their heads, and hold their breath when diving by closing it. These mammals can dive for long periods of time and to very large depths because of the efficient oxygen storage pigments in their blood and their ability to redirect blood from non-essential organs to essential ones.

Cetaceans use a series of whistles and clicks as echolocation to communicate with other members of their group, and also to navigate and find prey. They are all extremely intelligent and adapted to live in large open stretches of sea in contact with many others. Anglesey Sea Zoo does not keep such creatures in captivity because no aquarium can do justice to their natural habitat.

The main threat to cetacean populations locally is from fishing. Cetaceans are competing for ever-dwindling stocks of mackerel and herring, and often get caught up in the nets used to catch these fish. The transparent mono-filament nets are lethal because they hold the animal under water so they quickly drown. Many pollutants such as plastics, chemicals and sewage are also extremely harmful. Plastic bags are often mistaken for jelly-fish or squid and if swallowed can block up the stomach. Chemicals can become concentrated in fish and then can cause nervous and other medical problems in the mammals that eat them.

About twelve species of cetaceans can be seen around the coast of Britain. The Harbour porpoise and the Bottle-nosed dolphin are the most commonly spotted around Wales, with the most regular sightings in Cardigan Bay. Whales are seen far less often because of their tendency to stay further off-shore, and to dive deeper for longer periods.

About thirty-five cetaceans strand each year on the coastlines of Britain. The majority tends to be larger whales that have made navigational errors and regularly end up on the shores of northern Scotland. Success in getting these creatures back in to the water depends on their reason for stranding. The most common reasons for stranding are illness and navigational mistakes, with mass strandings usually due to a group following one individual to shore. If the animals are healthy, then the prognosis is usually good, particularly if they are not stranded for long.

In association with Green Seas, the Anglesey Sea Zoo has set up a response centre for these stranded mammals. This was as a result of a successful rescue of a rare striped dolphin, which was stranded on Anglesey in 1995.
Basic rescue equipment is held on site and trained members of staff are available to respond quickly to any reports of a local stranding. A network of people and organisations, who can respond to a stranding, is being built up around the British Isles by the British Divers Marine Life Rescue (BDMLR). They run training courses and help with providing essential equipment for basic maintenance and refloating of cetaceans.

On discovering a stranded cetacean, which is still alive, it can be reported to the following organisations:

• Keep the animal wet (and shaded from sun if possible)
• Turn animal onto its belly (if not already) taking care not to damage the flippers
• DO NOT put water down the blowhole
• Try and keep the area quiet and keep dogs and large numbers of people away

To contact us email: info@angleseyseazoo.co.uk