On a tenuously related note, Netflix is not only offering BLACKFISH on demand (Good for Netflix!), but another documentary that talks about how the shrinking of Arctic ice, while bad for polar bears, has increased the hunting grounds of orcas. Alas, this does not bode well for belugas and narwals: a polar bear may kill a single beluga whale if it finds a pod's breathing hole, but a group of orcas will kill and eat entire pods of belugas and narwals.
The scientists interviewed didn't think belugas and narwals were in danger of extinction, but the invasion of the killer whales has made safe "nursery" inlets dramatically UNsafe. The scientists believe belugas and narwals may be pushed farther north to whatever remains of Arctic ice. (Orcas can't handle sea ice well because of their huge dorsal fins.)
BTW, despite SeaWorld's repeated claims that orca dorsal fins droop at the same rate in the wild as in captivity, this is the umpteenth documentary I've seen in which NOT A SINGLE wild orca had a drooping dorsal fin. Obviously, this is anecdotal evidence and I haven't done a formal study, but I'm very suspicious of the "at the same rate" claim, since I've never seen a film of orcas in captivity where at least half didn't have drooping dorsals.