White-beaked dolphins are large,robust dolphins with an average body length of 2.7 m.They have a short but distinct beak which is usually white or light grey. Some animals in the south of their geographical range are reported to have dark or even black beaks. White-beaked dolphins have a very prominent dark dorsal fin mid-way along the back, which is large and sickle shaped.The dorsal fin, flukes and pectoral fins are a uniform dark grey. A distinctive white or pale-grey saddle is present behind the dorsal fin and is characteristic of this species.Two white patches are normally found on the flanks, one either side in front of the dorsal fin and the others on the flank behind the dorsal fin.These patches may merge into the pale saddle behind the dorsal fin. They are strong swimmers, and often swim very energetically along the surface and breach on occasion.They occasionally bow ride vessels, especially larger ships. The data collected includes observations, relative abundance, search for and range of White-beaked Dolphin (Lagenorhynchus albirostris) 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.

Long-finned pilot whales are very large and robust dolphins with an average body length of 6.7 m for males and 5.7 m for females. A low bushy blow is often visible and quite audible when in close proximity to the animals.The head is bulbous, with a very short and poorly defined beak.The bulbous melon is quite prominent in males and may overhang the beak. The dorsal fin is located slightly before the half-way point along the animal’s back and is large, with a very broad base and rounded at the tip. The pectoral fins are long,sickle-shaped and pointed at the tip. Long-finned pilot whales are black in colour with a white anchor-shaped throat patch and white belly patch. Some animals display a paler grey saddle patch behind the dorsal fin. Calves are lighter in colour and often appear to have a brown tinge. Long-finned pilot whales can be very active at the surface and commonly breach, tail slap and spy-hop. The data collected includes observations, relative abundance, search for and range of Pilot Whale (Globicephala melas) 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.

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.

The common bottlenose dolphin is one of Irelands most recognisable cetacean species.They have a robust, muscular body shape with an average body length: of 1.9m – 3.8 m.The body colour is grey with a light grey (that can show variations of grey patterns) or white underside.A tall falcate dorsal fin with a broad base sits half-way along the back. Bottlenose dolphins exhibit a moderately keeled tailstock. The head has a short,rounded beak with the lower jaw protruding slightly beyond the upper. A soft mouth line curves upwards at back to give the familiar‘smile’ that is characteristic for this species. They often approach vessels to bow ride in inshore waters and in the Shannon Estuary and frequently display acrobatic activity at the surface. Conversely offshore animals often appear wary of approaching vessels. The data collected includes observations, relative abundance, search for and range of Common Bottlenose Dolphin (Tursiops truncatus) 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.

Grey seals are the largest seal species in Irish waters. Male grey seals are considerably larger than females, growing up to 2.6 m in length. Females grow up to 2 m in length.The coat is dark grey on the back and flanks with a lighter underside and with irregular black mottling over the entire animal. Grey seals have a ‘Roman nose’ shaped muzzle. Newborn pups have a white coat and pups are born approximately one meter in length. The data collected includes observations, relative abundance, search for and range of Grey Seal (Halichoerus grypus) 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.

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.