12 February 2010
Basking Shark (Cetorhinus maximus)
(Photo courtesy www.sharkireland.com)
The Basking Shark is endangered in the Pacific and in trouble in the Atlantic (COSEWIC 2007, listed as vulnerable by the IUCN) and is little known by most humans. A call to our lab to determine which “sea monster” carcass had washed up on a Nova Scotia shore had us discover a Basking Shark that had apparently died at sea.
These gentle giants can grow up to 15 metres in length and have the longest known gestation period of any vertebrate (up to 3.5 years!), so replacement is low. Despite their size, I think Basking Sharks are pretty cute. First, they’re filter feeders, so the fear factor is totally related to being humungous and able to knock your head off with a casual flip of the tail. Second, their rounded noses make them look a bit more like a seal than a shark. Unfortunately, they can become tangled in nets and fishing lines or hit by ships as they cruise near the surface of the water, feeding on the rich biodiversity of plankton there.
I’ve been up close and personal with a lot of Atlantic sharks, and their sheer bulk makes them seem invincible. They aren’t. In the pacific, the situation is even worse.
What can you do to help them out? As with any ocean fish, this is a tough question. Avoiding cruise ships is a good first step, but minimizing your contribution to water pollution (salts, fertilizers, sewage? learn more here) and eating a vegetarian diet (slower global warming and no nets or lines to tangle or maim non-target species) are even better. Finally, tell your friends! We’re the species responsible for their decline, so we can certainly act to change that.