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An infographic appearing the diversities between the 3 orca ecotypes that are living alongside the coasts of California and Oregon and the possible distinctive inhabitants. Credit score: UBC
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An infographic appearing the diversities between the 3 orca ecotypes that are living alongside the coasts of California and Oregon and the possible distinctive inhabitants. Credit score: UBC
UBC researchers imagine a bunch of killer whales noticed looking marine mammals together with sperm whales, in addition to a sea turtle, within the open ocean off California and Oregon generally is a new inhabitants.
In accordance with to be had proof, the researchers posit in a brand new learn about revealed in Aquatic Mammals that the 49 orcas may belong to a subpopulation of temporary killer whales or a novel oceanic inhabitants present in waters off the coast of California and Oregon.
“The open ocean is the biggest habitat on our planet, and observations of killer whales within the prime seas are uncommon,” mentioned first writer Josh McInnes, a grasp’s pupil on the UBC Institute for the Oceans and Fisheries (IOF). “On this case, we are starting to get a way of killer whale actions within the open ocean and the way their ecology and behaviour differs from populations inhabiting coastal spaces.”
3 ecotypes of killer whales are living alongside the coasts of California and Oregon: ‘citizens,’ ‘transients,’ and ‘offshores’.
The unknown orcas had been noticed earlier than, however the brand new paper comprises a weight of proof collected from 9 encounters with 49 animals from 1997 to 2021, sufficient to shape a cast speculation, the researchers mentioned.
“It is lovely distinctive to discover a new inhabitants. It takes a very long time to assemble footage and observations to acknowledge that there is something other about those killer whales,” mentioned co-author Dr. Andrew Trites, IOF professor.
The 49 killer whales may no longer be matched with any identified animals thru footage or descriptions. “In probably the most first encounters researchers had with a pod of those oceanic killer whales, they had been noticed taking over a herd of 9 grownup feminine sperm whales, in the end making off with one. It’s the first time killer whales had been reported to assault sperm whales at the West Coast,” mentioned McInnes.
“Different encounters come with an assault on a pygmy sperm whale, predation on a northern elephant seal and Risso’s dolphin, and what looked to be a post-meal lull after scavenging a leatherback turtle.”
Shark scars supply essential clues
A key clue to the brand new inhabitants’s presumed habitat vary lies in cookie-cutter shark chew scars noticed on nearly the entire orcas. This parasitic shark lives within the open ocean, that means the brand new inhabitants essentially inhabits deep waters a ways from land.
The orcas additionally function bodily variations from the 3 major ecotypes, together with of their dorsal fins and saddle patches—the grey or white patches by way of the fin.
“Whilst the dimensions and shapes of the dorsal fins and saddle patches are very similar to temporary and offshore ecotypes, the form in their fins numerous, from pointed-like transients to rounded-like offshore killer whales,” mentioned McInnes. “Their saddle patch patterns additionally differed, with some having huge uniformly grey saddle patches and others having easy slim saddle patches very similar to the ones noticed in killer whales in tropical areas.”
In conjunction with marine mammal inventory evaluate surveys, fishermen and passengers on an open-ocean birding expedition and whale-watching excursion additionally equipped observations of the unidentified killer whales, mentioned Dr. Trites. Recognizing the brand new inhabitants has turn out to be one thing of a passion amongst fishermen, a few of whom have purchased cameras for his or her journeys particularly to snap an come across, the researchers mentioned.
The researchers hope to report extra sightings and acquire additional info, together with acoustic information concerning the orcas’ calls and genetic data from DNA samples to research additional how those killer whales might fluctuate, or no longer, from already documented populations.
Additional info:
Josh D. McInnes et al, Proof for an Oceanic Inhabitants of Killer Whales (Orcinus orca) in Offshore Waters of California and Oregon, Aquatic Mammals (2024). DOI: 10.1578/AM.50.2.2024.93
