Identifying Distant Large Whales off the East Coast

If you follow www.norfolkcetaceans.wordpress.com you will know that last Tuesday a large whale was seen off Winterton here in Norfolk. Although the identification was inconclusive it was thought by at least one of the individuals who saw it to have been a Humpback. I attended as soon as I could and spent the rest of the day trying to get a glimpse of the whale … without success. It was not until the following day when the Whale was relocated at Mundesley were sufficient features noted to put its identification beyond doubt.

It’s always difficult when cetaceans are distant to be sure what you are seeing so I thought I’d put down a few pointers of what to look for when faced with a distant large whale in the North Sea. It goes without saying decent binoculars and a spotting scope are essential.

The first thing to consider is what a large whale off Norfolk could be. So what large whales regularly occur in the North Sea? The rouquals (whales with baleen plates in their mouth) Minke, Humpback, Sei and Fin are not adverse to the reasonably shallow waters of the North Sea. Of the toothed whales, Sperm Whales have occurred but are not regular. This list excludes Bottlenose Whale, the Pilot Whales and Beaked Whales as I’m not considering them as ‘large’; though if I was in the water face to face with a Sowerby’s Beaked Whale I might change my mind.

Here are some identification points for large whales in the order of most probability of their occurrence.

The blow of a Minke is very rarely seen except in particularly cold and damp conditions. The dorsal fin is sickle shaped and shows at the same time as the blow. Minke’s rarely breach.

The blow of a Humpback is very visible and bushy. The dorsal fin is squat, rounded and positioned after a bump on the back which gives the animal its name. It’s a performer, often shows its long pectoral fins and flukes as well as often breaching.

A whale to consider that hasn’t (officially) been seen off Norfolk is the Fin Whale. They are large. They are the second largest animal on the planet. They too have a sickle shaped fin but it is set far back on a long body and therefore appears just after the blow. They have asymmetrical colouring on the head. The right side is white. The left is dark. The white patch sometimes extends up the right side in a chevron shape behind the blowhole. The blow is up to 6m in height is narrow and cone shaped.

Sei Whales have never been seen off Norfolk. Intermittent in size between Minke and Fin the blow is seen simultaneously with the fin which is erect and curved on the back edge.

Blue Whales have also not yet been recorded in Norfolk and there are few records from the North Sea. However, they are certainly not strangers to shallow waters. The fin often doesn’t appear until the whale is about to dive and looks small compared to the size of the animal. The blow is up to 9m tall. The colour of Blue Whales is surprisingly ‘bluish’.

In the distant past there is evidence that Sperm Whales have been seen offshore but if they stay they invariably die as they require squid as both a source of food and a source of liquid sustenance. All whales derive their fluid they need from the food they eat. Squid require deep water to survive; far deeper than what the North Sea offers. Sperm Whales have a nobly back rather than a true dorsal fin.

So the features to look for on a distant large cetacean, in order of importance are:

Fin shape

Shape and size of blow

Size of animal

When the fin shows relative to blow

Any breaching

Any colouring seen

A Fin Whale I photographed in the Hudson River showing the sickle shaped dorsal fin