If you haven't seen it already, check out the National Geographic channel for a show called "The Whale That Ate Jaws." It's about an orca who chomped down a great white in a seal rookery off the coast near San Francisco a few years ago, in a prime feeding area for great whites. Within hours after the fracas, biologists noted that the entire area was completely clear of sharks, and they stayed away for weeks - maybe months; I can't recall exactly.
This inspired them to run a series of experiments, and they eventually determined that the scent of dead shark in the water causes all other sharks in the area to get as far away as possible as fast as possible. The thinking is that - sharks being an apex predator - anything that can kill one shark is so unusually dangerous, all other sharks want absolutely no part of whatever the heck did it.
Just to provide a little backstory to flesh out the info in the clips, marine biologists say that there are three distinct "cultures" of orcas in the Pacific. These cultures are large, loosely associated communities, almost like tribes, that have generally distinct geographical ranges and a lot of shared knowledge and habits. That's apparently the origin of the term "culture" in this particular usage; they teach other within their group, and each group shares a specific set of common knowledge. Some cultures specialize in hunting seals, because that's the main prey in their territory, and they have a specific skill set that's suited for killing seals. Other cultures have skill sets that are better suited to killing different types of animals, and don't seem particularly talented at killing seals.
The gist of it is, they think that an orca from a southern culture that is known for killing sharks either ranged up to the San Francisco area and killed this one, or taught the technique to an orca from a northern culture. If you know this going in, you'll probably understand the clips a little better.