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.

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.

Common dolphins are Irelands most widespread and abundant dolphin species.They have an average body length: of 1.7 – 2.6 m.The beak, and back are dark brown to black, and the underbelly is white. The front flank patches are yellow and the rear flanks and the sides of the tailstock are streaked light grey. These features give a distinctive hourglass pattern on the sides, below the dorsal fin.The eye is surrounded by black, and a narrow stripe runs forward to the melon.Another dark stripe runs from beak to flipper and several beak-to-anus stripes may also be visible. A falcate dorsal fin is located mid-way along the back.The general body shape is sleek with the head having a prominent black beak. Common dolphins often approach vessels to bow ride and frequently breach clear of the water. Melanism is sometimes seen in this species, with elanistic animals lacking yellow pigmentation, which is replaced with black. The data collected includes observations, relative abundance, search for and range of Common Dolphin (Delphinus delphis) 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.