It is said that an orca’s eyesight is equally good in or out of the water. In fact it is thought they use eyesight when ‘spyhopping’ to spot boats that may present a danger. Orca do not seem to fear boats but once a motor is turned off and no sound is coming from the boat it becomes harder for them to locate. “Orcas possess sophisticated underwater sonar that enables them to perceive their surroundings ten times more effectively than our most advanced equipment.” (http://www.orcafree.org) However a boat’s shallow draft may make it harder to locate and thus the need for an occasional spyhop. Great photo from James Wendy of Australia.
A wild orca often travels far, and quickly, in deep water. The water provides pressure to the fin, keeping the tissues inside healthy and straight, and encouraging the dorsal fin to remain straight. However, it is not impossible for a wild orca’s dorsal fin to collapse or become bent. A study in 1998 of killer whales in New Zealand showed a relatively high rate (23%) of collapsing, collapsed, or even bent or wavy dorsal fins, and noted that this was higher than that observed in populations in British Columbia or Norway. It has been found from a well-studied group of wild killer whales (the ones in our viewing area) off the coast of British Columbia that the total rate of dorsal fin collapse is around 1%. This is only the second collapsed fin I have seen in ten years. Researchers have theorized that dorsal fin collapse in wild whales may be due to age, stress or altercations with other killer whales.