A male orca travels quickly near a large cargo ship transiting through the Salish Sea. Image taken under NOAA permit.

An orca "spyhops" at the surface, a behavior believed to help the animal view an area above water. Image taken under NOAA permit.

An orca chases a salmon to the surface. Often orcas will reposition and "process" their prey near the surface, prior to tearing it apart and sharing with others in its group. Image taken under NOAA permit.

A 9-year-old southern resident male from K pod swims with a Dtag temporarily stuck to its back by neoprene suction cups. The waterproof tag contains two underwater microphones, pressure and temperature sensors, triaxial accelerometers and magnetometers to help researchers understand how orcas move through the water and interact with their environment. A whale-watching vessel is visible in the distance. Image taken under NOAA permit.

A southern resident pod transits past a ferry — part of the Washington State Ferries system — in the Salish Sea. Image taken under NOAA permit.

A northern resident orca initiates a dive while wearing a Dtag temporarily stuck to its back by neoprene suction cups. The waterproof tag contains two underwater microphones, pressure and temperature sensors, triaxial accelerometers and magnetometers to help researchers understand how orcas move through the water and interact with their environment. Image taken under NOAA permit.

Southern resident orcas travel in the Salish Sea as a whale-watching vessel is visible in the distance. Image taken under NOAA permit.

In this photo from November 2007, southern resident orcas swim tightly alongside a newborn orca. Image taken under NOAA permit.

A group of southern resident orcas with the Seattle waterfront in the background. Image taken under NOAA permit.