Evaluating the Population-Level Impact of the Ocean Shrimp (Pandalus jordani) Trawl Fishery on the Southern Distinct Population Segment of Eulachon (Thaleichthys pacificus), Information Reports 2014-06

Identification Information

Citation

Originator: Hannah, Robert W.

Publish Date: 2014

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Cedric Cooney

Job Position: Natural Resources Data and Systems Manager

Telephone: 503-947-6094

E-Mail Address: cedric.x.cooney@odfw.oregon.gov

Description

Abstract: Eulachon (Thaleichthys pacificus), an anadromous smelt species inhabiting the Pacific coasts of the U.S. and Canada, is the first marine forage fish species to be listed as “threatened” under the U.S. Endangered Species Act (ESA, Gustafson et al. 2012). Specifically, the southern “distinct population segment” (SDPS) of eulachon has been determined to be both a species, as defined by the ESA, and at moderate risk of extinction over the next 100 years (Gustafson et al. 2012). The SDPS is comprised of eulachon spawning runs ranging from northern California to the Nass River in northern British Columbia (Gustafson et al. 2012). The factors causing the recent declines in the abundance of SDPS eulachon are not well understood, however, climate change, changes in the abundance and distribution of predator populations, bycatch in the ocean shrimp (Pandalus jordani) trawl fishery and changes in the timing of peak river flows due to dams and water diversions have been identified as potential contributors (NMFS 2010). Interpreting the significance of the recent declines in SDPS eulachon abundance is very challenging. Eulachon are primarily a marine fish, spending very little of their lives in fresh or brackish water (Hay and McCarter 2000). No estimates of the marine population size are available, and inferences about population trends are based on limited data on spawning run sizes from several larger river systems (Gustafson et al. 2012). There is also a lack of information on the magnitude of natural multidecadal variation in the abundance of SDPS eulachon, in comparison with the more extensive time series available for other Pacific forage fish species such as northern anchovy (Engraulis mordax), Pacific sardine (Sardinops sagax) and Japanese sardine (Chavez et al. 2003, Yasuda et al. 1999).

Purpose:

Time Period of Content: 1968-2013

Geographic Extent: Oregon

Status: Final

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Format: PDF

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