Dear marmam community, I am pleased to announce my recent publication in Aquatic Mammals.
García-Cegarra, A.M. 2022. Evidence of Type A-like killer whales (Orcinus orca) predating on marine mammals along the Atacama Desert coast, Chile. Aquatic Mammals
2, 48(5), 436-448, DOI 10.1578/AM.48.5.2022.436
Abstract
Killer whales (Orcinus orca) are marine apex
predators distributed across the world’s oceans.
In the last 40 years, researchers have increasingly
differentiated killer whales into ecotypes based
on genetics, morphology, behaviour, acoustic
repertoire, habitat, and trophic ecology. While
killer whale ecotypes in the Northern Hemisphere
are well studied, the recognition of distinct
killer whale forms in the Southern Hemisphere
is mainly limited to Antarctic waters. Although
present in less studied regions, such as along the
Atacama Desert coast in the Southeast Pacific
Ocean, limited information is available regarding
their biology or trophic ecology. Herein, multiple
lines of evidence are presented for killer whale
predation on marine mammals in northern Chile.
Using information from systematic boat-based
surveys, whale-watching tour surveys, and reports
from fishermen/citizen scientists, 19 killer whale
sightings are reported along the coast of northern
Chile (from the Arica and Parinacota region in the
north to the Atacama region in the south). Killer
whales were photo-identified as corresponding
to the Southern Hemisphere Type A-like ecotype
according to their dorsal fin shape and white eye
patch. One killer whale pod, which included two
males, one female, one juvenile, and one calf, was
resighted six times from 2016 to 2021 in northern
Chile and was observed hunting South American
sea lions (Otaria flavescens), dusky dolphins
(Lagenorhynchus obscurus), and long-beaked
common dolphins (Delphinus cf. capensis). Killer
whales were observed taking advantage of large
aggregations of sea lions associated with the offshore purse-seine fishery. Adult killer whales used
the hulls of fishing vessels to prevent sea lions
from escaping. Photo-identification analysis of a
fin whale (Balaenoptera physalus) catalogue from
Mejillones Peninsula showed that 2.6% of all
identified whales had apparent rake marks from
killer whale teeth on their dorsal fins. These data
show that Type A-like killer whales in northern
Chile prey on several species of marine mammals.
All the best
Ana
Ana M. García-Cegarra, Ph.D.