Barred knifejaw

The barred knifejaw (Oplegnathus fasciatus), also known as the striped beakfish, is a species of marine ray-finned fish, a knifejaw from the family Oplegnathidae. It is native to the north-western Pacific Ocean, though a smattering of records exist from other localities in the eastern Pacific such as Hawaii and Chile. Recently introduced – probably via ballast water – in the central Mediterranean, it is found very rarely from Malta to the northern Adriatic.

It is an inhabitant of rocky reefs and occurs at depths from 1 to 10 m. Juvenile members of this species can be found with patches of drifting seaweed. This species can reach a total length of 80 cm, with the greatest recorded weight for this species of 6.4 kg. The color pattern consists of light and dark vertical bars from which it derives its name. The species feeds mainly on hard-shelled invertebrates such as crustaceans and molluscs. It is a commercially important species and is also farmed. It is also sought after as a game fish.

Tsunami fish
Five barred knifejaws endured more than 2 years in the partially submerged hull of the Japanese boat Saishoumaru (斎勝丸). The tsunami fish is the last surviving specimen those five knifejaws.

The boat broke loose and went adrift during the March 11, 2011 Tōhoku earthquake and tsunami. On March 22, 2013, the boat washed onshore in North America at Long Beach, Washington, more than 4000 mi from its starting point. The fish, as of December of 2013, resides at the Seaside Aquarium in Seaside, Oregon.

The Tōhoku earthquake occurred on March 11, 2011, and was the most powerful reliably measured earthquake in Japanese history. The resulting tsunami swept the 20 foot Saishoumaru out to sea and inundated its storage compartments with seawater containing marine life, including several knifejaw fry. During the ensuing two-year drift across the Pacific Ocean, the fish matured into juveniles. Scientists speculate that the fish were deposited into the ghost ship by sea waves either off the coast of Japan or Hawaii.

The boat was discovered beached on the Washington coast on March 22, 2013, its internal hold now forming an "aquarium" for the five knifejaws as well as more than 30 plant and invertebrate species. Four were euthanized shortly after their discovery by the Washington Department of Fish and Wildlife, due to the concerns that the warm-water fish could become an invasive species. The fifth was brought to the city hall in a bucket, after which the Seaside Aquarium agreed to add the fish to their collection. As of late 2013, the fish is on display at the aquarium.

Between 2014 and 2015, divers spotted at least one other specimen in the wild off the coast of California, again argued to have travelled on or in debris from the tsunami.