Icelandic Killer Whales

Killer whales in south Iceland. Date Unknown. Photo provided by Filipa Samarra.

### Common Features

Large, round eyepatches that hook towards the front; smaller in size compared to other ecotypes; round heads and melons; tall, straight dorsal fins; subtle subocular notches (mouth chips); closed saddle-patches.

### Distribution

North Atlantic ocean, primarily Icelandic waters.

### Notable Individuals

* SN0113 "Riptide"
* Keiko
* Tilikum
* Kiska

## Conservation

### Threats

* Environmental contaminants (i.e. PCB's)
* Entanglement
* Ship strike

The Icelandic killer whale population is a population of wild orca primarily found in the North Atlantic waters surrounding Iceland. This population, it's social structures, and seasonal movements are still poorly understood as research within this population only recently began.

### Population and Identification

The Icelandic killer whale population is managed by two main identification catalogs based on Iceland's most abundant herring grounds. These are the west Iceland and south Iceland catalogs. The west Iceland killer whale catalog is by far the most expansive catalog of Icelandic killer whales with over a thousand individuals recorded in the catalog as of 2022. This catalog records and keeps track of the west Iceland killer whales, the part of the Icelandic orca population that is primarily found in Breiðafjörður in Snæfellsnes and is managed by Orca Guardians Iceland, a non-profit killer whale research organization. The south Iceland catalog is managed by the Icelandic Orca Project in collaboration with the Icelandic Marine and Freshwater Research Institute (MFRI) and keeps track of the south Iceland killer whales, the part of the Icelandic orca population that is primarily sighted off of Iceland's south coast and around the Vestmannaeyjar (the Westman Islands) archipelago.

Individuals within these two regions are cataloged and assigned an alphanumeric identification number in both catalogs if they have been observed in both regions. Some individuals are only recorded in one of the two catalogs. Icelandic killer whales are identified by two main alphanumeric ID systems. One beginning with ***IS*** for south Iceland (eg. ***IS076***) and the other beginning with ***SN*** for Snæfellsnes, west Iceland (eg. ***SN090***). The numbers on both ID's do not necessarily stay the same and will represent the order in which the individual was added to each catalog. Some individuals have been known to make seasonal migrations to Scotland and may be given an additional ID number from Scottish researchers.  This makes it possible for one Icelandic killer whale to have up to four unique ID numbers if the individual has been matched elsewhere or had been assigned an ID from an older catalog such as the MFRI catalog. An example of this is SN065 ''Defiance'' who had four unique IDs at the time of her passing.

#### The Start of Photo-ID Research

Killer whale photo-identification efforts in Iceland began in the 1980's when the Icelandic Marine and Freshwater Research Institute was the first to establish a photo-ID catalog of known Icelandic killer whales. Photo-ID research became more persistent in 2008 when the Icelandic killer whale research project 'Icelandic Orca Project' was the first to establish a dedicated photo-ID program in south Iceland and have since become the longest running killer whale research project in Icelandic waters. In 2016 the non-profit organization Orca Guardians Iceland was established and began recording and cataloging individual killer whales near Snæfellsnes, west Iceland. Over 1,000 individual killer whales have been recorded and cataloged in both west and south Iceland combined as of 2023.

###### Available photo-ID catalogs:

* Killer whales of **west Iceland** (Mrusczok, 2014-2017).

* Killer whales of **west Iceland** (Mursczok, 2011-2022).

* Killer whales of **south Iceland** (Samarra, 2006-2015).

* Matrilineal catalogue of Icelandic killer whales (Mrusczok, 2014-2023)

### Social Structure

Although most killer whale groups are often made up of matrilines, research has shown that the Icelandic killer whale population tends to be more flexible with social associations, and groups will often split up or travel with different, unrelated individuals. Icelandic killer whale groups are not named after matrilines like other populations may be. Instead, all well-known groups or pods of known individuals are assigned a 'core group'. The core group is usually named after the most prevalent individual in the group (the individual who is most often around when the group is observed) and are made up of individuals that most heavily associate with one another. In most cases, these individuals are related. Core groups can be named after both female and male individuals.

### Seasonal Movements

The seasonal movements of Icelandic killer whales is not yet entirely clear, however, a few dozen individuals have been observed making seasonal migrations to Scotland each summer. The number of individuals known to make this migration becomes higher every year, as new individuals get matched between the two countries via photo-identification.

In June of 2022, three killer whales were matched between Iceland and Norway for the first time in history. They remain the only individuals to be matched between Iceland and Norway to date.

### Diet

Icelandic killer whales have been observed feeding primarily on Atlantic herring (*Clupea harengus*), however studies by the Icelandic Orca Project and various scientists in Iceland have revealed that different groups may often have varying feeding preferences. Some groups specialize only on herring year-round and are referred to as 'herring specialists' while others may switch to higher trophic level prey, such as smaller marine mammals. These individuals are referred to as 'generalists'.

### History

* In 1954, more than 100 killer whales were killed by the U.S Navy in Iceland using explosives dropped from aircrafts. The killer whales had been feeding on herring populations that were in decline due to overfishing and the government saw them as pests threatening the economy of the country's fishing industry.

* Between 1975 and 1989, a total of 64 killer whales were captured in Icelandic waters to be trained and sold to the aquarium industry. Out of the 64 wild-caught killer whales, three (Stella, Katina, and Ulises,) are still alive as of March 10th, 2023. There are currently 22 full-blooded Icelandic killer whales alive in human care, 19 of which are captive-born and descent from wild-caught Icelandic orca.

### Individuals

For a whole list of individuals in the wild Iceland orca population, see Icelandic Killer Whales (Category)

## References

1. ↑ Seasonal movements of killer whales between Iceland and Scotland.
2. ↑ A Multilevel society of herring-eating killer whales indicates adaption to prey characteristics..
3. ↑ Prey of killer whales (*Orcinus orca*) in Iceland