Today we had another fun day of with the Resident Killer Whales off San Juan Island! We watched a lot of foraging behavior today as the Orcas hunted for Salmon, in particular Chinook Salmon. One Salmon jumped high out of the water just in front of the boat, surprising a few of our passengers We also got to witness a lot of socializing between the Orcas today as they moved up and down the west side.
All recorded toothed whales are known to produce pulsed underwater sounds that they use on a regular basis to forage, navigate, and avoid predators; These sounds also help whales investigate objects from different angles to maximize amount of echoing information and easily discriminate small objects. They produce “click trains” or pulses of broad-frequency clicks. These clicks strike an object, and part of the sound energy is reflected back “heard” by the whale and interpreted.
Clicks can be repeated up to 600 times per second (in the case of bottlenose dolphins)! The rate of click repetition is adjusted to allow the echo to return between outgoing sounds – the speed at which a click returns to the emitting whale from the object is a measure of the distance to that object. Additional echoes that are received may be interpreted to indicate the target’s speed and direction (if moving) – the click repetition rate increases as the whale closes in on the target.