Sara’s Crash Course in Marine ID Skills

A common question guests ask me when whale watching is: “What do we need to look for?”

It might sound obvious: “Well, you need to look for a whale, madam.”

However, the cetaceans that patrol the British coasts can be extremely elusive. Countless times have the footprints of porpoise appeared around the boat before quickly melting back into the surf, or splashes on the horizon have given away a pod of dolphins. But to the untrained eye they can look nothing more than waves.


Would you have realised this was the “footprint” of a Minke Whale?

How do you distinguish between a porpoise and a dolphin? How did you know that was a whale? How do you know where they’re going to come up?

Again, the questions I get asked on a daily basis! So, in the spirit of preparation for the Big Watch Weekend I’ve decided to give you all a Marine Mammal ID crash course so that on the 26th-27th July you can ditch sitting in front of the TV and head to your nearest spot of coastline and make the most of summer. Who knows what you’ll see? So – print out this blog, grab a camera and binoculars and head on outdoors.

Good signs for cetaceans:
Birds: I think people are surprised by how excited I get when I see a lot of bird activity. After all, we’re on a whale watching trip. But birds are a great indicators of the underwater activities, which you can’t see so easily. If you know where the birds are – then you’ll have a better idea of where the cetaceans (whales, dolphins and porpoise) are. Gannets are the best ones to look for – if you see these birds circling high above the water and diving, then there’s a high chance there are cetaceans driving the fish underneath them.


Baitball feeding


Gannet ID: Bright white feathers, black wing tips, yellow head and almost a 2 metre wing span!

Calm weather: you can be the best wildlife guide in the world but if the weather isn’t right, you simply won’t be able to see anything. Undoubtedly the best weather for whale watching is flat calm water (i.e. no wind at all!) and slightly over cast so you don’t get bright glare from the sun. Sea State 0-2 is the best, but I’ve still managed to see minke whales in a Sea State 6 (albeit I was clinging on for dear life). Click here to learn about Sea States.

How to identify cetaceans when you’ve found them:
Harbour Porpoise:
These are the most common cetacean in British waters – yet they are the hardest to see! You need very calm waters to see these shy creatures as they gently break the surface. Porpoise can be notoriously difficult to photograph because they are so shy, so you need a lot of patience.
Porpoise ID:
• Triangular dorsal fin (avoid confusion with the curved dorsal fin of a dolphin)
• 1.5-1.9 metres in length
• Very small/little splash
• Shy personality – in contrast to dolphins, porpoise won’t spend time jumping at the surface (other than the necessary for breathing!)
Best place to see them: All around the UK coast but the North Sea (between Newcastle – Hull) and the West Coast of Scotland (Firth of Lorn) are two good places.


I took this photo last week. It’s a good example of how calm the water needs to be to see small and shy porpoise…can you spot it?


Bottlenose dolphins are very confident, energetic and quite frankly totally the opposite of porpoise regarding personality. They often head towards boats to swim with them (bow ride) and investigate what’s going on.
Britain’s most common dolphin – Bottlenose Dolphin ID:
• Look for lots of splashes and acrobatic jumping.
• Curved, gun-metal grey dorsal fins.
• These dolphins can reach up to 3.9 metres in length – they’re big!
Best place to see them: Moray Firth (Scotland) and Cardigan Bay (Wales).


With a bit of practice the splashes of dolphins on a calm day are unmistakable – even at a distance!

White Beaked Dolphin ID:
• Black, curved and pointed dorsal fins.
• White/grey saddle patches on the back.
• Most often seen in groups of 5-10.
• 3 metres in length
Best place to see them: North Sea (Northumberland coastline)


White beaked dolphins from a far – note the white saddle patches on their backs (and the calm weather! Any waves would make this difficult to spot from a distance)

Minke whales:
You can’t confuse a whale with a porpoise – but I suppose from a distance you can confuse it with a dolphin if you don’t get a good look at it.
Minke whale ID:
• They’re BIG! Up to 10 metres in length.
• Their dorsal fins are two thirds of the way along their body (unlike dolphins and porpoise which have them half way).
• Minke whales rarely splash (unless breaching of course).
• Look for a dark shape coming slowly out of the water (which contrasts with the quick, splashing movement of dolphins). They often surface 3-5 times before deep diving (signalled by a pronounced arching of the back). Once they’re down they can be gone for up to 20 minutes – by which time they could have easily travelled several kilometres away.

Best place to see them: West coast of Scotland


Note the dorsal fin of a minke whale is two thirds of the way along its body, unlike the central fins of dolphins and porpoise.

A lot of identifying wildlife obviously comes with experience – we’re all beginners at some point. I once confidently identified an eagle to everybody (which turned out to be a plane) and on another occasion a shark (which turned out to be a log). But you have to start somewhere! I think getting out to your nearest coastline will be a GREAT start.
Take your cameras with you and let me know what you see! If you’re not sure of any wildlife you photograph on your adventures, you can always send them through to me for a look.
Top tip: If you know the cetaceans are there but are having trouble spotting them, keep watching the behaviour of any birds (particularly gannets) and look underneath them! If there is feeding happening, more often than not the birds will lead you to the right spot.


For more about my life as a wildlife guide, watch my film “Wild Islands“!
Happy wildlife watching folks!

See Sara’s website here:


Photos: Sara Frost and David Ainsley


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