Alien fish discovered in crab pot


A fish native to Japan has been captured alive in a crab pot in the US.

The Striped knifejaw or beakfish, Oplegnathus fasciatus, which is also found in China and Korea, was discovered in a crab pot near Port Orford in southern Oregon.

The fish is around 13cm/5.2in in length, so not yet fully grown, and is being studied by scientists from Oregon State University and the Oregon Department of Fish and Wildlife. It may or may not be related to the Japanese tsunami of 2011, the researchers say, and it is premature to conclude that this non-native species may be established in Oregon waters.

In March 2013, five Striped knifejaws were found alive in a boat near Long Beach, Washington, that had drifted over from Japan. Four of the fish were euthanised, but one was taken to the Seaside Aquarium, where it is still alive and well.

OSU marine ecologist Jessica Miller examined the four euthanised knifejaws from Washington in 2013, analysing their otoliths, or ear bones, for clues to their origin.

"The young fish of these species are known to associate with drift and may be attracted to floating marine debris," Miller said. "Japanese tsunami marine debris continues to arrive on beaches in Oregon and Washington — and some debris from Japan washed up on the southern Oregon coast this month — so it is not inconceivable that the Port Orford fish was associated with Japanese marine debris.

"The species is also found in other parts of Asia and the northwest Hawaiian islands, so it is native to a broader range than just Japan," she added. "At this time, there is no evidence that they are successfully reproducing in Oregon."

Tom Calvanese, an Oregon State graduate student researcher working with Oregon Sea Grant on the start-up of a new OSU field station in Port Orford, worked with the fisherman to secure the exotic species. "It appears to be in good shape and was swimming upright, though it had a small cut in its abdomen," Calvanese said. "I talked to Keith Chandler at the Seaside Aquarium who suggested feeding it razor clams, which it took readily."

The fish will be transported to a quarantine facility for the time being.

Sam Chan, an OSU invasive species expert, has seen Striped knifejaws in Japan and estimates this fish may be one or two years old.

"Therefore, it is unlikely to have left Japan in the 2011 tsunami," Chan said, "but a boat could have been milling around Asian waters for the past 2-3 years and then picked up the fish and ridden the currents over. The big question is — are there more of these?”

Chan said Oregon Sea Grant — an OSU-based marine research, education and outreach programme — would work with Oregon fishermen, crabbers and others to keep a lookout for additional Striped knifejaws and other exotic species.

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