Peter Pyle's First Hand Account of Killer Whale / White Shark Encounter
9 October 1997, 9:41 am
Veteran Farallon Island biologist Peter Pyle of the Point Reyes Bird Observatory witnessed
the recent encounter between a killer whale and white shark. He kindly shares his observations with us.
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| It was a very amazing sight, the orca with a 10' white shark in its mouth.
Above-water video taken aboard the vessel "New Superfish," captured it somewhat.
Here's the from-island account: |
| At about 10:30 am the two orca (apparent mother and calf) were seen by a sport
fishing boat ("C-Gull") killing and eating a California Sea Lion off the
west end of the island. We saw the gulls and pelicans circling the event
but it was out of view from our vantage to the southeast. I had to do a
boat landing at 11:30 am. As I was doing that (offloading people and
equipment) the fishing boat came over and told us of the encounter. I
called the New Superfish and they were heading for the orca at that point. I
finished the landing and called the Superfish again to learn that the orca
had a large shark in its mouth. Two volunteers and I immediately jumped in
our 17' shark research whaler and headed out to the event, which was
occurring just north of the island. When we got there the calf orca was
dragging the shark through the water. It had grasped the shark by the
dorsum, just caudal to the pectoral fins. From our vantage we could see
the underside of the shark from the pectoral fins forward, all white except
for the tips to the pectoral fins, which were black. I later learned that
this was diagnostic of white shark in our area (it looked like a white
shark to me but I was hesitant to be 100% sure it wasn't, e.g., a large
salmon shark, without confirmation). From our vanatage we could not tell
if the shark's tail was present or not but I believe it was (see below).
I estimated the length from the posterior edge of the pectorals to the
snout to be 4.5-5.5 feet. |
| It was a bit hard to know what to do at this point. Orca are very rare
here and I have not had close encounters with them before. We did not want
to approach too closely for fear of disturbing the orca or inciting the
wrath of the adult female, so we circled slowly toward the calf/shark. It
was also quite rough and hard to control the boat precisely. About five
minutes after we got there part of the liver popped out of the shark. The
gulls were in a feeding frenzy on the liver and other bits of the shark
floating to the surface. At this time we secured a piece of the liver for
species documentation and genetic analysis. We saw the calf drop the shark
carcass and head for the liver. We rushed over to the carcass and I was
able to get some underwater video (with out shark-research pole camera) of
the carcass sinking. A phytoplankton bloom was occurring so the only thing
visible on the video is a fuzzy outline of the carcass receding into the
depths. On the video the carcass appears essentially to be entire,
although it is possible that what looks like the tail may actually be
entrails. At this point the boat had drifted close to the liver and I was
able to obtain several underwater video sequences of the calf eating the
liver. Scot Anderson was on his way out from the coast and arrived at this
time. He also got some underwater video of the two orca. |
| Based on accounts from the Superfish, it appears as though the
adult female orca killed the shark then later gave it to the calf. We
wonder now if the killing was for 1) food, 2) protection of the calf,
and/or 3) removal of a competitor for a prey resource here. Orca are so
rare here and pinnipeds so abundant that I doubt the last hypothesis.
Since the orca did not appear to be actively feeding on the shark we
wonder about the 2nd option. Feedback will be welcome. Based on the video
the orca have been tentatively identified as belonging to a southern
California "offshore" pod that feeds more on fish than mammals. We will,
of course, be writing this up when all is said and done. |
9 October 1997, 12:59 pm
Peter submitted the following addendum:
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| Having seen the video tapes on the news, whale researcher Alisa Schulman
has identified what we thought was the calf as an adult female. This
could be. We estimated the animal to be 12-15 feet in length which may be
typical of a small adult female. Perhaps this indicates that the other
animal (the one that killed the shark) was a subadult male. We will
be reviewing all of the videotape and photographs to sort this out in the
end. |
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