The Washington state task force on orcas in Canada voted Tuesday to temporarily stop all tour boats on the Salish Sea from watching endangered southern resident orcas. The initiative intends to reduce boat noise that interferes with orcas' hunting and communications.

Orcas, also named "killer whales" are not whales, but the largest of the dolphin family. These hefty fellows in their neat black suit and white shirt are apex predators. They feed on marine mammals such as seals, sea lions, and even whales, which deserve the name of “whale killer”.

While transient killer whales feast on marine mammals, resident killer whales primarily prefer fish and squid. The endangered southern resident killer whales especially love chinook salmon, whose abundance greatly impacts their living.

As a cosmopolitan species, orcas can be found from Arctic and Antarctic regions to the Equator. Although their total population in the world is unknown, some local ones like the southern resident killer whale now are endangered. It is said that only 74 southern resident killer whales live in the Pacific Ocean, which hits a 35-year low.

Apart from boat noise targeted by the initiative, southern resident killer whales also suffered from decreased salmon supplies and water pollution. According to a study published in this September, half of the world's orca populations are close to extinction due to toxic contaminants in the oceans, and they could vanish in as soon as 30-50 years.