Orcinus orca L., 1758
Family: Delphinidae

The killer whale or orca is the only toothed whale that is regularly seen in Northern Ireland waters. These highly intelligent predators are easily recognized and usually occur in family groups (pods) of 5-20 individuals.

In brief

• Found in the seas around Northern Ireland
• Can be seen at any time of the year
• Often seen in groups (pods)
• Listed as a UK priority species

Species description
The killer whale is the largest member of the dolphin family. Adults are 5.5-9m long; males are larger than females. They have a very distinctive colour pattern – mostly jet-black on top, with an obvious white patch above and behind the eye, a whitish-grey patch behind the dorsal fin and a white chin, throat and belly. The flippers and tail are black. Male killer whales have an enormous, black, triangular dorsal fin that can be up to 1.8m tall. The female’s dorsal fin is about half this size and more curved.
There are 20-26 pairs of large, interlocking, pointed teeth in the upper and lower jaw. One blow hole is present and the blow is a single, low, bushy cloud.

Life cycle
Killer whales are social animals and live in family groups (pods). They are found throughout the world’s oceans. At the top of the food chain, they eat a variety of prey, including fish, seals, dolphins and other whales. They may travel large distances to find food and are amongst the fastest animals in the sea - speeds of up to 55km per hour can be maintained for short bursts. Acrobatic displays, jumping out of the water (breaching), spy hopping and tail slapping are often seen.
Killer whales become sexually mature at around 11-14 years of age. Pregnancy lasts about 17 months and a single calf can be produced every 4-6 years. The calf weighs around 180kg at birth and measures 2-2.5m; it is suckled for at least a year. Killer whales may live for up to 50 years in the wild with females usually living longer than males. In captivity, life expectancy can be as low as 10 years.

Similar species
Risso’s dolphin and the pilot whale may be confused with the killer whale. Different body colouration is the main identification feature. Risso’s dolphin is pale grey with heavy scarring, pilot whales are jet black or dark grey, while killer whales have very obvious black and white markings.

How to see this species
Sightings off the coast of Northern Ireland have increased over recent years as whale watching becomes more popular. The best places for whale watching are headlands, islands and bays when the sea is calm. The sea off Whitehead and Blackhead, Co. Antrim is a good place to see killer whales.

Current status
The population for the eastern north Atlantic is estimated to be around 3,500-12,500 animals.

• Protected under Schedule 5 in the Wildlife (Northern Ireland) Order 1985
• Listed in Schedule 2 of the Conservation of Habitats and Species Regulations 2010
• Listed in Appendix II of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention)
• Listed in Appendix 2 of the Convention on Migratory Species (Bonn)
• Covered by the terms of the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS)
• Listed in Annex IV (Animal and Plant Species of Community Interest in Need of Strict Protection) of the EC Habitats Directive
• Listed in Annex A of EU Council Regulation 338/97 and therefore treated by the EU as if they are on CITES, Appendix I, thus prohibiting their commercial trade
• Listed in Schedule 2 of the The Conservation (Natural Habitats, etc.) Regulations (Northern Ireland) 1995
• Listed under Appendix II of CITES

Why is this species a priority in Northern Ireland?

• Listed as UK Priority Species

Threats/Causes of decline

• Pollution
• Prey depletion
• Fishing nets and lines
• Capture for display in marine aquariums and parks
• Habitat disturbance

Killer whales are at the top of the marine food chain. Any contaminants in their food will accumulate in their bodies and may cause disease and breeding difficulties.

Conservation of this species

Current action
Killer whales are included in the UK Biodiversity Grouped Species Action Plan for toothed whales, which was published in 1999.

• Post mortem and tissue studies are carried out on stranded whales to establish the cause of death and condition of the animals at the time of death
• In 2008 the Northern Ireland Environment Agency initiated a cetacean monitoring programme to provide information on the distribution and relative abundance of cetaceans in Northern Ireland waters. The information collected will enable the future selection of marine protected areas for cetaceans

Proposed objectives/actions

• Avoid accidental harm to whales and dolphins when present in Northern Ireland waters
• Contribute to international measures for the conservation of whales and dolphins

What you can do
To report killer whale sightings to CEDaR, Telephone 028 9039 5264 or email cedar.info@nmni.com.

Further information

Links
Irish Cetacean Review 2000-2009, The Irish Whale and Dolphin Group

UK Grouped Species Action Plan for toothed whales

Joint Nature Conservation Committee (JNCC) priority species page

NBN Gateway: Killer Whale (Orcinus orca) grid map

Irish Whale & Dolphin Group

Cetaceans of Northern Ireland - Sea Watch Foundation

Whale and Dolphin Conservation Society (WDCS)

Literature

Text written by:
Angela Ross

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