The Dorsal Fin

The video above from NatGeoTV.com presents a theory that a killer whale from the L.A. Pod of orcas might have used tonic immobility during a 1997 attack on a great white shark at the Farallones. The theory suggests that the orca (identified as “CA2″) potentially rammed the unsuspecting white shark, stunning it. While the shark was still disoriented the orca could have either grabbed the great white while it was on its back or flipped it over. The orca could have then held the shark upside down in its jaws, keeping it in a state of tonic immobility until the shark drowned.

While there is no hard evidence or clear-cut video footage of orcas inducing tonic on sharks in the NatGeo feature, the video does include video evidence of killer whales attacking stingrays in New Zealand using a similar technique. As seen in the footage, the killer whales approach the rays upside and grab them with their mouths, then right themselves, so that the rays are upside-down and effectively immobilized. Researchers hypothesize that if orcas have learned to use this technique on rays, then it’s not far-fetched to assume they could use a similar technique on sharks.

On a side note, some of the underwater footage of the “great white shark” in this clip features a shark that is clearly not a white shark. While I admittedly am not great at identifying certain species of sharks, I’m guessing the footage features either a lemon shark or a bull shark. Anybody care to enlighten me on the species seen at around 3 minutes in?

Thanks to DeepSeaNews.com for the video find.

Numerous media outlets are reporting that a female Sea World Orlando employee was fatally attacked by an orca today. Orlando’s Local 6 identifies the orca involved as Tillikum, a 12,300 lbs. male. Park manager, Dan Brown, identified the victim as being one of the park’s “most experienced trainers.” According to the Local 6 report, the victim slipped and fell into the orca’s tank and was subsequently attacked by the orca.

Unfortunately, it seems that orcas have become just as susceptible to media sensationalism as sharks. This ABC clip is a prime example…

The clip plays out more like a guy announcing a pro-wrestling match than it does a news story. This is an incredibly tragic story, as such, it needs to be handled objectively with journalistic integrity, instead of being covered like it was a monster truck rally.

An incident which occurred at the Farallon Islands, on October 4, 1997, involving an orca attack on a white shark has somehow become “news” this weekend, at least on the ABC News website. The incident which was documented on video (and has been available on YouTube for years) is currently being featured on National Geographic Channel’s Wild series in an episode titled “The Whale That Ate Jaws.”

I have no idea why this story is back in the news this weekend (except for the fact that there’s a NatGeo show about it), although it is an interesting story, nonetheless. Also of interest was the resultant observed behavior of white sharks around the Farallon Islands after the predation occurred. According to a National Wildlife Magazine article the white sharks typically found around the Farallon Islands from September to December simply “vanished” after the orca attack on the white shark. The sharks did not return until the next fall. For a more in-depth discussion of the October 1997 event, as well as information about the “L.A. pod” of orcas and a possible second orca attack in 2000, check out the Showdown at Sea from National Wildlife Magazine.