Update at the bottom of the post…

When you’re close to five metres in length, with a set of chompers that are primed to do the job, you’d expect to be top of the food chain.

Alas, it appears that the great white sharks of Gansbaai are playing second fiddle, with a string of carcases washing up on shore after what many are saying are orca attacks.

Earlier this week a 4,9-metre female washed up in Franskraal, a coastal village very close to Gansbaai, and it’s only fuelled the idea that killer whales are on the prowl.

Marine Dynamics has this to say via Facebook:

At 7:00 am this morning another deceased white shark was reported in at the beach in Franskraal. This is the 5th white shark carcass, and the largest to wash up in Gansbaai since 2012, says Alison Towner, biologist for the Dyer Island Conservation Trust.

“The shark is a 4.9m female (total length) and we estimated her weight at 1,110kgs. We have her recorded around Dyer Island last year in June but we haven’t seen her since” says Towner. “She has also been recorded in Mossel Bay between August and December 2016. At this size, she is likely reproductively mature- which is rare to see and so impressive. Again there is much speculation flying around about Orcas killing the shark. There is a gaping wound on the sharks underside but until we have examined the injuries closely we cannot confirm if her death is indeed Orca related or not”.

“It’s is a very interesting time,” says Towner, “the last white shark washed up here on the 8th of February and the cage diving boats struggled to see any sharks for almost two weeks. Unfortunately the cage diving boats all came home after seeing no sharks again today. We are incredibly grateful to the members of the community that helped us locate the shark this morning and will update with more accurate information on the cause of death and findings after the autopsy tomorrow.”

They have yet to update their page with the autopsy results, but then there’s this from Imke Meyer, who was also on the scene:

This morning I witnessed the largest white shark dissection in South Africa! At 4.9m with a wound below the pectoral fin, speculation was that she was attacked by an orca, but without teeth marks this was uncertain. Upon opening up the shark they found the liver missing and it became clear that an orca must have removed the liver from this shark as this behaviour has been observed before.

Orcas are truly impressive.opening up the shark they found the liver missing and it became clear that an orca must have removed the liver from this shark as this behaviour has been observed before. Orcas are truly impressive.

This from Harry Stone’s Facebook post, which comes with the main image at the top of the post:

I was lucky enough to attend today’s necropsy of the white shark recovered in Franskraal yesterday. It was a poignant yet fascinating experience. The animal was just shy of 5m long, making her the largest white shark dissected in South Africa, and had a bite wound just below her pectoral fins. The scientists conducting the examination discovered that the shark’s entire liver was missing, which when coupled with repeated orca presence in the area lately, and previously recorded behaviour, seems to point to them being the cause. We await the official report.

So by now, you’re maybe thinking hang on, you said ‘sharks’ – plural.

Well how about the very next day – again from Marine Dynamics:

Another white shark has been found on Franskraal beach today at 5pm. Our team went straight there to recover the 3.4m male who is missing big pieces out of each flank. Alison V Towner, marine biologist with Dyer Island Conservation Trust and Dr Malcolm Smale, will conduct the dissection tomorrow at International Marine Volunteers and notify the results.

This specimen is in a more degraded state and cannot be frozen. We will notify further information just bear with us during this extraordinary time.

These are extraordinary times we live in, friends.

Let’s hear from GrindTV before we call it a day:

In some areas, orcas commonly prey on other types of sharks.

Last December off Monterey, Calif., a pod of offshore killer whales passed around a large sevengill shark that it had killed. That was captured via drone-cam.

In New Zealand, orcas commonly prey on smaller sharks.

Ingrid Visser, who has studied killer whales for nearly 20 years, told the Telegraph that orcas use a specialized technique to stun their prey: “The orca will use its tail to drive the shark to the surface. They don’t even touch it. Using an up-thrust of its tail it creates a vortex which pushes the shark up on the current they create with their movements.

“Once the shark is at the surface, the killer whale pivots and lifts its tail out of the water and comes down on top of it like a karate chop.”

Great, they’re evolving.

Jokes aside we’re keen to see what comes out of those autopsies, and if anyone manages to capture an orca / great white shark hunt on film we would be much obliged.

UPDATE: This from the Shark Spotter’s Facebook page:

The last 2 days have been fascinating and insightful regarding the interactions between white sharks and killer whales (Orca’s) in Cape waters. On the 2 May a 4.9 m female white shark was found dead along a Gansbaai beach.

There was a large gaping hole between her pectoral fins where they were torn apart to reveal her body cavity, but it wasn’t until we performed a necropsy (animal autopsy) yesterday that we discovered that her large liver (which can constitute up to a third of her weight) was completely missing.

This information, combined with the recent sightings of Orca and disappearance of white sharks in the area, provides convincing evidence that the Orca are responsible for the shark’s death. Further evidence mounted following the discovery of a second shark, a 3.5 m male in the same area, with the same wounds last night.

There has been much speculation about the influence of Orca presence on white sharks, and now we can finally say with certainty that the Orca (at least some of them) do predate on white sharks in South Africa and most likely do influence their behaviour and movement patterns.

We would like to thank Alison Towner and the whole Dyer Island Conservation Trust team for coordinating and facilitating a timely necropsy, to DEA for permitting us to do so and to all the scientists and community members for their participation and support.

[sources:facebook&facebook&facebook&grindtv]