Why are marine mammals washing up dead?

A young killer whale found dead at Point No Point, near Victoria. (Stefan Beckmann/DFO)

Answer 1: Life’s tough, and more to the point, finite. So, animals die, even the charismatic ones that humans like. That’s Nature.

Answer 2: Some thing, or things, are happening in the ocean, and these are signs of that.

I don’t know what the answer is, but there have been a lot of stories lately about marine mammals washing up dead on B.C. beaches.

I’ve certainly reported on a few for CBC News. For example:

• The Department of Fisheries and Oceans told me yesterday they’re “concerned, but not panicking” about at least eight harbour porpoises that have washed up dead in recent days on southern Vancouver Island. Maybe they were hunted to exhaustion by transient killer whales, or the weaker ones died during breeding season, or something else. The provincial government’s Animal Health Centre in Abbotsford is conducting necropsies starting today. [Update: now, at least nine porpoises have washed up in five days.]
• A brand new killer whale calf just washed up near Victoria. Again, the cause of death is not known, and the Animal Health Centre is investigating. Here’s my story interviewing the veterinary pathologist on the case. Survival is low among newborn killer whales, so the death itself isn’t surprising, but some populations of them are so endangered this death was treated (a) as an urgent case and (b) as an opportunity to learn more about what’s going on.
• There have also been at least five grey whales washing up north and south of the border (CBC) (The Province). This is apparently not unusual; it happened at the time when grey whales pass here on the way from their breeding grounds in Baja to their feeding grounds in B.C./Alaska.

Does this all add up to anything? I don’t know. Just because they’re all marine mammals doesn’t mean it’s wise to list these cases together. Plus, the media has a habit of paying extra attention to something its already paid attention to (meaning the later strandings would get more coverage).

The good thing is: it appears that someone’s watching. When I interviewed Dr. Stephen Raverty, the veterinary pathologist on these cases, he noted that prior to 2000 most marine mammal strandings were not investigated. Now, he says 70-80% are, thanks to the efforts of DFO and NOAA. His lab now examines hundreds of marine mammal carcasses each year.

The hope is, if something is going on, these individual cases will yield some clues to protect the rest of the population.

Do you have any questions or thoughts about what’s going on?