Your host, Francisco is one of very few orca experts in Portugal. The popular idea of orcas being cold waters animals is wrong. The orca is the 2nd most worldly distributed mammal on Earth, loosing only to humans. They can be found in ALL oceans and regularly sighted in ALL continents, from warm tropical seas to ice covered seas in the poles. Orcas can even be sighted in the Red Sea, Persian Gulf, Mediterranean and Hudson Bay. Only being absent from the Black and Baltic Sea.

This makes  existence of orcas in Portugal nothing out of the extraordinary. Specially with the recent growth of dolphin watching companies, which enabled regular sightings of this species. These orcas seen in Lisbon belong to the Iberian orca population, a fish eating ecotype. They are the same individuals regularly seeing in the Strait of Gibraltar, Spain. The small number of individuals in this population (30s) imposed special protection, and since 2014 they had been designated by the IUCN as “critically endangered”.

However historical data in Portugal is scarce, but the oldest record we’ve found is from 1927, when a group of 5 orcas was sighted southwest of Lisbon (Pereira, 2012). In Spain, Iberian orcas records are far older, dating back almost 3 millennia. Back then, Phoenician fishermen from Gadir (today’s Cádiz, Spain) had already acknowledged the presence of orcas as both where after the Bluefin tuna. Pliny the Elder, a famous Roman naturalist, described how orcas preyed on baby whales near the Bay of Cádiz (Hickok, 2018). These whale species are slow swimmers, the North Atlantic right whale (Eubalaena glacialis) and the Atlantic grey whale (Eschrichtius robustus). This characteristic allowed the orcas to prey on them and humans to hunt from small boats. These whales ended up hunted down to extinction, by European whalers during the Middle Ages. The remain species are rorquals, fast swimming whales, that for this reason, are not suitable to hunt. This situation lead to the complete removal of whales from the feeding “menu” or to the extinction of those whale families/groups.

These orcas seen in Lisbon belong to a genetically distinct population from the orcas that occur in higher latitudes of the Northeastern Atlantic (North Sea, Iceland and Norway), belonging to the same genetic population as the orcas in the Canary Islands (Foote et al., 2011). However it seems that these groups (Iberian) do not interact with the individuals from the Canary Islands, as they do not share the same parasite load (Mackenzie, 1999; Dwyer & Visser, 2011) nor similar food sources (Esteban, 2013).

Off South Portugal, in the Strait of Gibraltar (where these orcas seen in Lisbon spend the summer time), have been studied for decades and identified at an individual level. During spring and summer months, they are regularly seen in the Strait, which is associated with the migration eastern stock of Atlantic bluefin tuna, into the Mediterranean for spawning (Guinet et al. 2007; de Stephanis et al. 2008).