Scuba Diving with Sharks published an article yesterday on sharks and scuba divers. The article is a part of a common attempt to dispel the myth of man-hunting sharks.

One diver interviewed for the article, Hank Parfitt, frequently swims alongside shark, and even acts as a shark wrangler for underwater photo shoots. The most practical bit of the article is Parfitt's tip on giving an angry shark its space.

When is a shark angry? Parfitt gives three signs:

  1. Pectoral fins angled down. A neutral to happy shark will swim with its pectoral (side) fins straight out, like an airplane. If you see them angled down, the shark is upset, hungry, defensive, or some non-friendly emotion. Give it some distance.
  2. Arched back. My guess is that an arched back is like a spring, getting the shark ready to dart at potential food or something it feels may harm it.
  3. Shaking its head back and forth. In conjunction with the previous two, a shark shaking its head like it's saying "no" is not happy and may be aggressive.

Calm sharks are easy to observe. A few brave like Parfitt will even touch the shark, but always in front of the dorsal fin. Like all animals, the rear is particularly vulnerable, so avoid sneaking up on a shark (even if it's unintentional). When treated with the respect they deserve, scuba diving with sharks can be a great experience.