Practical Boat Owner - January 2016

Identifying ocean giants

Wikimedia/NASA

Save the Whales/Kate Cummings

Whaleopedia/NOAA http://www.animalspot.net

Part of the larger group known as toothed whales, dolphins and porpoises are the cetaceans most likely to be seen by boat owners. However, distinguishing between the different species can be difficult. They often travel at great speed and, unless they are jumping or swimming very close to the boat, you only spot splashes or the

dorsal fin. The dorsal fin is usually sickle-shaped and centrally placed and appears very similar for all species at first glance, although slight differences do exist. If you do get a good look at the body, the different species can be distinguished by looking at the colouration and patterns, behaviour and size.

Dolphins and porpoises

Atlantic white-sided dolphin(Size:Lagenorhynchus acutus 2-2.8m )

Distinctive markings:head with short, thick and dark beak. Sloping

Large sickle-shaped dorsal fin, centrally placed. It has a black back with an elongated yellowish band extending backwards on the side, while the sides and belly are paler grey

and white. White-sided dolphin ID:tall curved fin; yellowish patch extending backwards, and no white on the back behind Active at surface;

the fin.

en.wikipedia.org/Erik ChristensenHarbour porpoise(Phocoena phocoena (^) )
Size:Distinctive markings:The harbour porpoise has a short, blunt head with no forehead or beak. The 1.5 -1.7m
colouration is dark grey on the back with a paler patch on the sides and a white belly. Harbour porpoise ID:is the smallest cetacean in UK waters. The The harbour porpoise
dorsal fin is uniquely triangular. The harbour porpoise is not an acrobatic species, and it is common to see just a glimpse of the dorsal fin from the surface.
Short-beaked common dolphin(Size:Delphinus delphis 1.7-2. 5m )
Distinctive markings:groove separating the forehead from the long and slender black Distinct
beak (sometimes with white tip). Common dolphin ID:is dark grey on the back with a characteristic hourglass pattern on the side. The hourglass The common dolphin
has a yellowish patch in front and a pale grey patch on the side behind the fin.
Bottlenose dolphin(Size:Tursiops truncatus 1.9-3.9m )
Distinctive markings:and stubby beak, like a bottle. The dorsal fin is tall and centrally Short
placed. The back is uniformly grey with paler grey sides and a lighter belly. Bottlenose dolphin ID:acrobatic behaviour. The large size and, Often displays
ironically, the absence of distinctive markings make this dolphin distinguishable from other species.
worldofprehistory.wikja.comWhite-beaked dolphin(Lagenorhynchus albirostris (^) )
Size:Distinctive markings:Sloping head with a short and distinctive 2-3m
white beak. Colouration is black on the back with lighter patches on the sides and over the back and tail stock.White-beaked dolphin ID: The most
distinctive identification feature is the pale grey area that extends from the upper sides in the front and across the back behind the dorsal fin. If the species is viewed from
above, close to the boat, the white beak will also be noticeable.
Risso’s dophinSize:Distinctive markings: 2.6-3.8m (Grampus griseus )
Blunt, rounded head and no beak. Tall and
slender dorsal fin. Dark grey back and sides, but turns lighter with age (due to scarring). Risso’s dolphin ID: Risso’s dolphins are
recognised by the heavy scarring unique to this species, assumed to be caused by other individuals of the species. It is often regarded as calm compared to other dolphin species. ➜