barred knifejaw (Oplegnathus fasciatus)

Oplegnathus fasciatus
(barred knifejaw)
Marine Fishes
Exotic

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Oplegnathus fasciatus (Temminck and Schlegel, 1844)

Common name: barred knifejaw

Synonyms and Other Names: Western Pacific barred knifejaw

Taxonomy: available through www.itis.gov

Identification: The barred knifejaw has a deep, strongly compressed body with seven distinct black vertical bands, the first band is through the eye, and a caudal fin is edged in black (Jordan and Fowler 1902). Large adult males differ from juveniles and females in that they have a black snout without the vertical bars on the body (Masuda et al. 1984). The teeth in each jaw are fused, together forming a sharp beak (Masuda et al. 1984).

Size: Up to 80 cm TL (Masuda et al. 1984)

Native Range: This species is found in the Western and Central Pacific Ocean and is endemic to Japan, the Ogasawara Islands, and the Hawaiian Islands (Mundy 2005).

Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: Barred knifejaws were discovered in two Japanese fishing vessels, which were found off the west coast of the United States after being set adrift during the 2011 tsunami. Five specimens were collected inside the wet well of a derelict vessel in Long Beach, Washington, in March 2013. In April 2015, a single knifejaw was found in a vessel off Seal Rock, Oregon (Ta et al. 2018). In February 2015, a single knifejaw was found in a crab pot along North Beach, just off the Elk River in southern Oregon (Ta et al. 2018).

From December 2014 - October 2015, several individuals were observed in the Monterey Bay area, California (Ta et al. 2018).

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Oplegnathus fasciatus are found here.

State	First Observed	Last Observed	Total HUCs with observations†	HUCs with observations†
CA	2014	2015	2	Monterey Bay; Northern California
OR	2015	2015	2	Alsea; Sixes
WA	2013	2013	1	Willapa Bay

Table last updated 3/28/2025

† Populations may not be currently present.

Ecology: In Japan, this species breeds from April to July. Adults inhabit coastal rocky reefs (Nakabo 2002). The juveniles float among seaweed and feed on zooplankton (Masuda et al. 1984). Adults use their sharp beak to feed on snails and barnacles (Masuda et al. 1984).

Means of Introduction: Most likely rafting on tsunami debris (Ta et al. 2018)

Status: There have been no observations of O. fasciatus in Monterey Bay since October 2015 (Ta et al. 2015).

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: Oplegnathus fasciatus is highly valuable as a food and game fish in Japan (Masuda et al. 1984).

References: (click for full references)

Jordan, D.S. and Fowler, H.W. 1902. A review of oplegnathid fishes from Japan. Proceedings of the United States National Museum 25:75-78.

Masuda, H., Amaoka, K., Araga, C., Uyeno, T., and Yoshino, T. eds. 1984. The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo, Japan, 437 pp.

Mundy, B.C. Checklist of the fishes of the Hawaiian Archipelago. Bishop Museum Bulletins in Zoology 6, Bishop Museum Press, Honolulu 704 p.

Nakabo, T. ed. 2002. Fishes of Japan with pictorial keys to the species. English edition. Tokai University Press, Tokyo, Japan. 1474 pp.

Ta, N., Miller, J.A., Chapman, J.W., Pleus, A.E., Calvanese, T., Miller-Morgan, T., Burke, J., and Carlton, J.T. 2018. The Western Pacific barred knifejaw, Oplegnathus fasciatus (Temminck & Schlegel, 1844) (Pisces: Oplegnathidae), arriving with tsunami debris on the Pacific coast of North America. Aquatic Invasions 13(1):179-186.

Other Resources:

Author: Brown, M.E. and P.J. Schofield

Revision Date: 10/31/2018

Peer Review Date: 10/31/2018

Citation Information:
Brown, M.E. and P.J. Schofield, 2025, Oplegnathus fasciatus (Temminck and Schlegel, 1844): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=2902, Revision Date: 10/31/2018, Peer Review Date: 10/31/2018, Access Date: 3/29/2025

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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