BP's voluntary Environmental Assessment identified seven species of cetacean 'likely' to occur in the vicinity of Block 204/24. These were:

'at least two large baleen whale species, the fin whale and humpback whale, as well as several smaller toothed whales, including the long-finned pilot whale, killer whale, white-beaked dolphin, Atlantic white-sided dolphin and common dolphin'.

The JNCC's European Seabirds at Sea database contains 3,000 records of ten different species recorded in the area during the last 16 years (Bloor et. al. 1996). These include minke whale, fin whale, sperm whale, harbour porpoise, bottlenose dolphin, Atlantic white-sided dolphin, white-beaked dolphin, killer whale, long-finned pilot whale and Risso's dolphin.

BP's list has several important omissions. There are at least five additional species which are highly likely to be encountered, including the minke whale, sperm whale, northern bottlenose whale, Risso's dolphin, and harbour porpoise. There is a second group of species, which, although not as common as those listed above, might also be expected, including the sei whale, striped dolphin, Cuvier's and Sowerby's beaked whales. Further, although rare in British waters, the northern right whale and blue whale have been recorded from the region in the past. The false killer whale and possibly bottlenose dolphin may be seen, and occasional and unusual visitors to these waters may also include narwhal and beluga whale. See also table 1.

Table 1. Seasonal Occurrence and Status of Cetaceans in waters west of UK and possibly Block 204/24.

Species	Seasonal Occurence	Status	Iucn Status	Documented Recent Sightings
Fin whale *	Most sightings June-Dec. Some present year round?	Mainly deep water. Sightings appear quite common	Vulnerable	Gunnlaugsson and Sigurjonsson (1990) Mayer et. al. (1993) Buckland et. al. (1992). Bloor et. al. (1996)
Humpback whale *	Most sightings April-Sept. Some winter records	Rare. Mainly deep water. Sightings seem to be increasing in recent years	Vulnerable	Evans (1995) Sigurjonsson et. al. (1989). Christensen et. al. (1992)
Long-finned pilot whale *	Year round (possible peak Aug.-Oct.)	Common. Wide distribution offshore from continental shelf. Sightings increasing since 1970's	Insufficiently known	Mayer et. al. (1993) Buckland et. al. (1993) (Sigurjonsson et. al. (1991). Hammond et. al. (1995). Bloor et. al. (1996)
Killer whale *	Year round	Widespread between Scotland and Faroes. Fairly common	Insufficiently known	Evans (1988). Bloch and Lockyer (1988) Gunnlaugsson and Sigurjonsson (1990) Sigurjonsson et. al. (1991). Hammond et. al. (1995). Bloor et. al. (1996)
White-beaked dolphin *	Year round, peak in summer	Common around Hebrides, Shetland and Orkney. Less pelagic than white-sided	Insufficiently known	Evans (1995) Evans et. al. (1993) Northridge et. al. (1995) Hammond et. al. (1995) Mayer et. al. (1993). Bloor et. al.(1996)
Atlantic white-sided dolphin *	Year round, peak in summer. May move offshore in winter	Common around Hebrides, Shetland and Orkney. Mainly pelagic	Insufficiently known	Evans (1995) Hammond et. al. (1995). Bloor et. al. (1996)
Common dolphin *	Year round, peak in summer	Common. Increasing off western Scotland and northern North Sea	Insufficiently known	Hammond et. al. (1995). Evans et. al. (1993). Mayer et. al. (1993)
Northern right whale +	Summer	Very rare. Very occasional sightings - off Hebrides, and Ireland	Endangered	Evans (1981)
Minke whale **	All year, probably peak in summer	Quite common. Widely distributed around Scotland, particularly in west and north	Insufficiently known	Evans (1995) Evans et. al. (1993) Northridge et. al. (1995) Gunnlaugsson and Sigurjonsson (1990) Oien (1991) Hammond et. al. (1995). Bloor et. al. (1996)
Sperm whale **	All year (peaks July-Nov.)	Rare, but sightings/strandings increasing? Distributed in deep water along Atlantic coast, particularly west and north Scotland	Insufficiently known	Gunnlaugsson and Sigurjonsson (1990) Sigurjonsson et. al. (1989). Sigurjonsson et. al. (1991). Bloor et. al. (1996)
Harbour porpoise **	All year	Common, wide distribution, coastal and offshore. Concentrations around Hebrides and Northern Isles	Insufficiently known	Northridge et. al. (1995) Evans et. al. (1993) Bjorge and Oien (1990) Mayer et. al. (1993) Hammond et. al. (1995). Bloor et. al. (1996)
Striped dolphin §	July-Dec	Rare, but increasing off western Scotland?	Insufficiently known	Bloch et. al. 1996 (strandings)
Sei whale +	June-Dec. (possibly some year round)	Rare. Occasional sightings off continental shelf edge west of Scotland and Ireland	Vulnerable	Evans (1992) Cattanach et. al. (1993)
Risso's dolphin **	All year, peaks May-Sept	Fairly common and widely distributed in coastal and offshore waters	Insufficiently known	Evans et. al. (1993) Evans (1995) Hammond et. al. (1995) Mayer et. al. (1993) Gill and Atkinson (1996). Bloor et. al. (1996)
Bottlenose dolphin #167;	All year	Locally common but rare in Shetland and Orkney	Insufficiently known	Bloor et. al. (1996)
Blue whale +	Summer	Very rare. Occasional sightings in deep water west of Scotland/Ireland	Endangered	Evans (1992) (sighting from 1977)
Northern Bottlenose whale **	All year, peak in summer	Fairly common ? Deep water distribution north and west of Scotland	Insufficiently known	Gunnlaugsson and Sigurjonsson (1990)
Sowerby's beaked whale §	All year?	Rare. Deep water species. Distribution may centre off Ireland	Insufficiently known	Evans (1980)
Cuvier's beaked whale §	All year?	Rare. Deep water species. Distributed west of Ireland and Scotland	Insufficiently known	Evans (1992)
False killer whale §	?	Very Rare	Insufficiently known	Evans (1992)
Beluga §	June-Nov	Very Rare	Insufficiently known	Shetland Times, 13th September 1996
Narwhal ˜	?	Arctic vagrant. Not sighted since 1949	Insufficiently known
IUCN Red Data Book Status Categories. Endangered: taxa in danger of extinction and whose survival is unlikely if causal factors continue operating. Included are taxa whose numbers have been reduced to a critical level or whose habitats have been so drastically reduced that they are deemed to be in immediate danger of extinction. Vulnerable: taxa believed likely to move into the Endangered category in the near future if causal factors continue operating. Included are taxa of which most or all of the populations are decreasing because of over-exploitation, extensive destruction of habitat or other environmental disturbance. Insufficiently known: Taxa known to be Endangered, Vulnerable or Rare, but where there is not enough information to say which of the three categories is appropriate
* Species identified as likely in vicinity of Block 204 by BP Environmental Assessment. ** Species omitted by BP assessment but considered likely in the area. + Highly vulnerable or endangered species which were common in British and Irish waters prior to over-exploitation and which may occasionally be seen in traditional habitat/migration routes west of Britain, and Ireland. @ Species detected acoustically in Atlantic Frontier waters during 1996. § Species which are rare in these waters but have been recorded in the past. ˜ Very unusual visitor