By Alexa Shasteen, Esq.
On September 24, 2019, the Native Fish Society, Center for Biological Diversity, and Umpqua Watersheds (petitioners) petitioned the National Marine Fisheries Service (NMFS) to initiate a status review of spring-run Oregon Coast Chinook salmon under the federal Endangered Species Act (ESA). Currently, they are included with their fall-run cousins as part of the Oregon Coast Chinook Evolutionarily Significant Unit (ESU). Petitioners assert that spring Oregon Coast Chinook form a distinct ESU that qualifies independently for listing under the ESA. They request NMFS initiate a status review to determine whether spring Oregon Coast Chinook constitute an ESU, and if so, whether they should be listed as threatened or endangered under the ESA.
Spring-Run Oregon Coast Chinook
Chinook are the largest Pacific salmon, typically reaching three feet long and 30-40 pounds as adults. Like other salmonids, spring Chinook migrate from the ocean to the freshwater streams of their birth to reproduce. But unlike many other salmonids that run in the summer or fall, spring Chinook migrate upstream in the spring while still sexually immature, pass the summer in freshwater, and spawn in early fall.
Spring Oregon Coast Chinook historically inhabited nine river systems between Tillamook Bay and the Coquille River: Tillamook River and tributaries, Nestucca River, Siletz River and tributaries, Alsea River and tributaries, Siuslaw River, North Umpqua River and tributaries, South Umpqua River and tributaries, Coos River, Coquille River and tributaries, and Salmon River. Spring Oregon Coast Chinook have been extirpated from several of these rivers; other rivers support tiny but dwindling populations. The North Umpqua River is home to the only significant spring Oregon Coast Chinook population; it sees returns of 2,500 to 16,000 spawners annually.
NMFS Evolutionarily Significant Unit Policy
The ESA defines a “species” eligible for listing under the ESA to include:
. . .any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature. 16 U.S.C. § 1533(16). However, the ESA does not define the term ‘distinct population segment.’
In 1991, NMFS developed the ESU Policy, which provides that a population or collection of populations of Pacific salmonids must meet two criteria to qualify as an ESU:
•The population must be substantially reproductively isolated from other nonspecific population units; and
•The population must represent an important component in the evolutionary legacy of the species.
In 1998, NMFS delineated the Oregon Coast Chinook ESU, which included both spring- and fall-run Chinook. At that time, NMFS decided not to list Oregon Coast Chinook under the ESA.
According to petitioners, new evidence shows that spring Oregon Coast Chinook qualify as a separate ESU and are thus eligible for listing under the ESA distinct from fall Oregon Coast Chinook. It has been presumed that spring- and fall-run Oregon Coast Chinook were genetically similar, but petitioners assert that several recent studies on the “. . .genomic basis for premature migration in salmonids demonstrate[ ] significant genetic differences underlie the phenotypic distinctions.”
In other words, spring Oregon Coast Chinook run earlier because they are genetically different from Chinook that run in the fall. As petitioners explain:
A main benefit of the spring-run phenotype is that it allows access to exclusive temporal and/or spatial habitat that is partially or wholly inaccessible, or in some cases, less suited to fall-run Chinook salmon….A profound benefit to the species (as well as to the fisheries and ecological relationships that depend on the species) is the spreading of ecological risk by increased spatial diversity, behavioral and life history diversity, productivity, and population size afforded by the presence of the spring run form.
The ESA Listing Process
If NMFS agrees with petitioners that spring Oregon Coast Chinook should now be considered a distinct ESU, the ESU will be potentially eligible for listing under the ESA. When considering whether a species or subspecies, including an ESU, is endangered or threatened, NMFS must consider:
•The present or threatened destruction, modification, or curtailment of its habitat or range;
•Overutilization for commercial, recreational, scientific, or educational purposes;
•Disease or predation;
•The inadequacy of existing regulatory mechanisms; or
•Other natural or manmade factors affecting its continued existence. 16 U.S.C. § 1533(a)(l).
The species shall be listed where the best available data indicates that the species is endangered or threatened because of any one or more of these factors. 50 C.F.R. § 424.11(c). Petitioners addressed all five factors in varying detail, but this article will focus on habitat destruction and the threat of human-caused hybridization between spring- and fall-run Chinook.
Habitat Destruction and Degradation
Petitioners assert spring Oregon Coast Chinook are threatened by habitat destruction caused by logging, dams and irrigation diversions, climate change, and other human activities. Logging and related road construction reduces stream shade, increases fine sediment levels, reduces instream large wood, and alters watershed hydrogeology, leading to sedimentation and warming that decrease salmonid access to the deep, cold pools they require for summer holding. Removal of water for irrigation and climate change also contribute to stream warming.
Lack of physical access to historic habitat is another threat to the spring Oregon Coast Chinook. There are nine dams and reservoirs in the North Umpqua River, and passage barriers exist on the South Umpqua and other waterways within the spring Oregon Coast Chinook’s historic range. The 77-foot Soda Springs Dam is the first barrier to passage on the North Umpqua. It was relicensed for 35 years in 2001 amid a decades-long battle between PacifiCorp and environmental groups. As required by the relicensing agreement, fish passage was completed in 2012, but a large coalition of advocacy groups continue to call for removal of the Soda Springs Dam.
Artificial Propagation and Hybridization
Petitioners identify artificial propagation (hatcheries) as another anthropogenic factor endangering the spring Oregon Coast Chinook. Intentional or inadvertent hybridization of spring- and fall-run coastal Chinook in hatcheries is a newly documented phenomenon that petitioners assert presents “a major, imminent man-made threat to the spring run population.” As petitioners explain, hybridization likely harms both spring-and fall-run Chinook by producing:
. . .intermediate phenotypes that typically migrate later than the indigenous spring-run fish, but earlier than the fall run. Such intermediate phenotypes are almost certainly maladapted to long-term survival in natural habitats, consistent with their absence from indigenous wild Chinook salmon populations.
In other words, summer-run Chinook do not naturally occur, and there is probably a reason for that.
Conclusion and Implications
Petitioners request the National Marine Fisheries Service designate critical habitat for spring Oregon Coast Chinook, to include “all known and potential freshwater spawning and rearing areas, migratory routes, estuarine habitats, riparian habitats and buffers, and essential near-shore ocean habitats.” Such designation, should it come to pass, could have far-reaching implications for Oregon’s forest products, agriculture, and fishing industries. Final resolution may be several years in the offing, but the first test of petitioners’ claims will be NFMS’ decision whether to initiate a status review.
