Moving to Alderney and starting work as the Communications and Outreach Officer, I knew that I wanted to get stuck in learning about as many species as possible. I couldn't forget, however, my roots; the dolphins. With a background in marine mammal science and dolphin acoustics, wherever I have visited or lived, I've always kept an eye open for fins at sea. 

What do they look like?

Bottlenose dolphins are what most people think of when you say 'dolphin'. They are big, stocky, grey dolphins, and the individuals around the UK and Channel Islands are the biggest in the world - they have lots of fat to deal with our cold waters!

Researchers can use the dorsal fins of bottlenose dolphins (the fin on their back) to tell them apart. Over the course of their lives, bottlenose dolphins can pick up lots of nicks and scratches, but these can be used as something like fingerprints to identify different individuals. Over time, photos of the same dolphins can be used to see where they travel, whether they are found with the same dolphins, if they are breeding, and much more about the population as a whole.

Where can they be seen around Alderney?

Here in Alderney, we are lucky to be visited by a resident population, who spend time in our waters all year round. The Channel Islands population is made up of around 600 individuals, making it the largest coastal population in Europe! Their presence contributed to the identification of the Channel Islands as part of the Western Channel Important Marine Mammal Area (IMMA).

How do dolphins use sound?

It can be pretty dark and murky in the sea, so vision isn't always the best sense to use. Instead, dolphins use sound. They communicate to each other through whistles, which promotes group cohesion, social behaviours, and coordinated feeding. Bottlenose dolphins also use signature whistles to identify themselves to each other - these are whistles that are unique to each individual dolphin, a bit like names in humans. 

Like bats, dolphins also use echolocation. They can produce clicks from near their blowhole, and can direct the beam of clicks they make using a big piece of fatty tissue in their head called a melon. The clicks bounce off of objects in the environment, telling the dolphin information about them like size and distance. This is how dolphins hunt for food!

Listen to some of the sounds bottlenose dolphins make here.

Why is the bottlenose dolphin an Alderney Key Species?

Even though they are abundant worldwide and our population is doing well, bottlenose dolphins face lots of threats, and they have important ecological value that we want to conserve. They are ecological indicators, which means that scientists can look at them to understand ecosystem health. As they are predators at the top of the food chain, effects lower down the chain are magnified when they reach the dolphins.

How you can help

• Submit your bottlenose dolphin photos and sightings to iNaturalist, iRecord, and the Alderney Biodiversity Centre website. You can also contact Living Seas Coordinator, Mel, at marine@alderneywildlife.org, or Kate (me!) at headofoutreach@alderneywildlife.org.
• If you are at sea (in a kayak or boat, for example) when you see dolphins, keep quiet and keep your distance. Dolphins must come up to the surface to breathe, so it is vital that there is nothing blocking them from doing so. It is illegal to intentionally disturb marine mammals (including dolphins, whales, and seals) anywhere in the Bailiwick.