Identification of beaked whales at sea can be difficult, especially of juvenile animals. Northern bottlenose whales are perhaps the most easily recognised due to their large size (adults can reach up to 9.8 m in length),robust body and prominent bulbous forehead and beak.They have a brown/olive colour and a prominent falcate dorsal fin located two-thirds of the way along the back (with adults often being mistaken for minke whales if the bulbous head is not seen).The pectoral fins are paddle shaped and sit into grooves on the flanks of the body. The data collected includes observations, relative abundance, search for and range of Beaked Whales recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Striped dolphins have a maximum body length of 2.6 m.They are a sleek dolphin species with a slender beak,similar in shape to common dolphin but slightly smaller.A falcate dorsal fin (dark grey in colour) is located half-way along the back. The body coloration consists of a dark grey cape extending from the beak to behind the dorsal fin. The flanks are a lighter grey, leading to pink-white undersides.A thin dark stripe runs from the eye to the anus (between the grey and white areas), while a broad dark band runs from the cape, just below the dorsal fin and tapers to a point on the flanks above the pectoral fins. The striped dolphin is a fast active swimmer which sometimes bow-rides, but not as frequently as the common dolphin, which it resembles in body size and shape. The data collected includes observations, relative abundance, search for and range of Striped Dolphin (Stenella coeruleoalba) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Rissos dolphins are very robust with an average adult body length of 3.2 m. At birth calves are grey (overall colour ranging from light to dark grey) with a paler underside.As they age, adult Risso’s become paler due to increasing levels of white scarring resulting from tooth rake marks gained during social interactions. Adult Rissos appear pale grey or largely white (depending on levels of scarring), particularly around the head. There is a white anchor-shaped patch on the chest and the underside of the belly is also typically white. The head is blunt and bulbous, with no evident beak.A distinct vertical cleft is evident on the front of the melon. A tall, dark and very prominent dorsal fin is located mid-way along the back. The tip may be rounded or pointed with a concave trailing edge. The pectoral fins are long, dark and sickle shaped. A small but noticeable blow may be seen at close range. Rissos dolphins can be very acrobatic at the surface with repetitive breaching and tail slapping. The data collected includes observations, relative abundance, search for and range of Rissos Dolphin (Grampus griseus) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Adult humpbacks range from 11-16 m in length, with females being slightly larger than males. The head is broad with a series of fleshy knobs on rostrum (and sometimes on the lower jaw), called tubercles. Body colour is black with white on the throat and belly. The pectoral fins are extremely long (one-third of the body length) with scalloped leading edges. They are typically white in colour but may have a dark upper surface, with white beneath.The tail fluke typically has a dark upper surface with white beneath, however the under-surface can be dark in some individuals. The scarring, colour pattern and shape of each tail fluke is unique and provides for identification and tracking of individuals. The dorsal fin is small with a broad base, raised hump in front and "knuckles" behind. The blow is typically low and bushy and has a distinct V-shape when viewed from directly behind or in front of the animal. The data collected includes observations, relative abundance, search for and range of Humpback Whale (Megaptera novaeangliae) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Killer whales are the largest dolphin species, with adults reaching up to 9.5 m in length.The blow is low and bushy with a sharp sound, audible from a distance. The head is rounded with an indistinct blunt beak. The triangular dorsal fin, located half-way along the back, is the largest of any cetacean species and reaches 1.8 m in height in males.The dorsal fin on females and juveniles is falcate and more dolphin-like. Body colour is jet-black above and on the flanks. They have white undersides with a white patch above and slightly behind the eye and a white patch stretching from the underside onto the flanks. A lighter coloured saddle patch varies in colour from white to grey to brownish. Identification at sea is easy if the group contains an adult male, which they almost always do, as there is no mistaking the male dorsal fin. Even females and sub-adults have a noticeably larger dorsal fin than other species. The striking body colouration is also diagnostic. The data collected includes observations, relative abundance, search for and range of Killer Whale (Orcinus orca) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

The fin whale is Irelands most common large baleen whale and grows to a maximum body length of 24 m in the north Atlantic. Body colour is grey with a white underside. The head is v-shaped with a prominent rostrum in front of the blowhole. Jaw-colour is asymmetrical with the right lower jaw being white in colour and the left being grey, this is diagnostic for the species. A pattern of light and dark grey chevrons is noticeable behind the head in good light conditions. The dorsal fin is prominent and located two-thirds of the way along the back. It is variable in shape, though typically falcate or triangular. The species produces a tall columnar blow up to 6 m high which is very noticeable. The blow can sometimes appear angled if the animal blows while surfacing from depth. This species almost never flukes or breaches in Irish waters. Lunge feeding at the surface is sometimes seen off the south coast. The data collected includes observations, relative abundance, search for and range of Fin Whale (Balaenoptera physalus) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Harbour porpoises are Irelands smallest cetacean species with an average body length of 1.5 m. Their body colour is dark-grey with a white underside extending up the sides a little beneath the dorsal fin. The head is rounded with no distinct beak. A small triangular dorsal fin is situated half-way along the back, with a slightly curved trailing edge.Typically no blow is visible but in calm conditions a short sharp exhalation can be heard, giving rise to the common name of ‘puffing pig’,sometimes used for this species. Harbour porpoises rarely approach vessels or breach clear of the water. The data collected includes observations, relative abundance, search for and range of Harbour Porpoise (Phocoena phocoena) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Atlantic white-sided dolphins are robust dolphins with a maximum body length of 2.8 m for males and 2.5 m for females.They have a short beak which is black above and white below.The dorsal fin, located half-way along the back is tall and falcate with a sharply pointed tip and a narrow base. The back and upper beak are black, as are the pectoral fins and flukes.The flanks are grey and a white band below the dorsal fin connects with yellow/mustard coloured broad band on either side of the tailstock. The body is robust, with a gently sloping forehead. The tailstock is strongly truncated.The pectoral fins are sickle shaped and pointed. This species can be very active at the surface, with breaching and tail slapping however it seldom bow rides and does not readily approach ships. The data collected includes observations, relative abundance, search for and range of Atlantic White-sided Dolphin (Lagenorhynchus acutus) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Sperm whales are Irelands most widespread and abundant deep water whale species and indeed may be the most abundant large whale species within the Irish EEZ. They have a maximum body length of 15-18 m.The body profile is characteristic, with a large square head with and under slung jaw.The head forms one-third of the overall body length. There is no true dorsal fin, but two-thirds of the way down the back is a raised dorsal hump and beyond this are a series of 4 or 5 knuckles.The pectoral fins are short and stubby, but the tail flukes are broad and powerful.The scarring and shape of each tail fluke is unique and provides for identification of individuals. Body colour is typically dark grey to brown. There are often white blotches on other parts of the head or body.The skin on the head is frequently patterned with circular scars formed by the suckers of giant squid on which the whales feed. They have a short bushy blow which is angled forward and slightly to the left (caution: the blows of other species may appear similar when surfacing at an angle).The blow sequence is characteristic with logging animals blowing every 20-30 seconds. The breathing rate increases as the animal prepares to dive. The data collected includes observations, relative abundance, search for and range of Sperm Whale (Physeter macrocephalus) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.

Blue whales are the largest whale species in the world and the largest animal which has ever existed, reaching a maximum length of 33 m. Calves are born at up to 7 m in length. Body colour is blue-grey, mottled with grey, white or silvery patches. The dorsal fin is tiny in comparison to the animal, roughly triangular in shape and is set three-quarters of the way along the back.The head has a broad, flattened, u-shaped rostrum.A single raised ridge runs from almost the tip of the rostrum to the very prominent splash-guard around the blowhole. Blue whales typically produce a very strong blow, rising in a single thick column 6-12 m high, however this is not a diagnostic feature in Irish waters where fin whales are common. Surfacing sequence is a tall columnar blow followed by a long muscular back and (after a period) the tiny dorsal fin. Approximately 20 % of blue whales fluke when deep diving and this trait is specific to individuals (COSEWIC 2002). The data collected includes observations, relative abundance, search for and range of Blue Whale (Balaenoptera physalus) recorded from marine mammals observations on board ships of opportunity between 2005 and 2011.