Offshore Killer Whale Facts
Offshore killer whales (Orcinus orca) are genetically distinct from both Southern Resident and Transient ecotypes, being more closely related to Residents than Transients. While there is limited knowledge of this ecotype, we have found that Offshore killer whales feed primarily on sharks and fish and can be found in the open ocean stretching from the eastern Aleutian Islands of Alaska to southern California.
Worn teeth of an offshore killer whale
DID YOU KNOW?
In the late 1980s, these killer whales were observed mainly offshore and were given the name “offshores.”
Field observations first documented sharks as prey of Offshore killer whales in 2011. Due to the tough nature of the shark’s skin, the teeth of Offshore killer whales have shown significantly more wear than that of Resident and Transient killer whales.
A serious cause of disease in Offshore killer whales can be traced to the mouth. Dental disease, specifically, periodontal and endodontic diseases, are common for this species. In the case of deceased whale strandings, the teeth are a vital component for assessing health when other tissue may no longer be a viable clue.
The population of offshore killer whales that ranges widely in continental shelf waters from southern California to the eastern Aleutian Islands is considered relatively stable and numbers about 300 individuals.