Presentation on theme: "Evolutionarily Significant Units and the U.S. Endangered Species Act Michael J Ford Northwest Fisheries Science Center Seattle, Washington."— Presentation transcript:
Evolutionarily Significant Units and the U.S. Endangered Species Act Michael J Ford Northwest Fisheries Science Center Seattle, Washington
Motivation behind ESU policy: U.S. Endangered Species Act allows listing of “distinct population segments” Series of ESA petitions in early 1990’s == need to define what a DPS is for Pacific salmon 1991 NMFS policy says a DPS == an ESU
Definition of an ESU: Population or group of populations that is 1) Substantially reproductively isolated, and 2) Is an important component of the evolutionary legacy of the species Waples (1991)
Application of ESU policy : Response to specific petitions Snake River sockeye, chinook, steelhead Lower Columbia River coho Sacramento River winter chinook
Application of ESU policy : Coastwide status reviews chinook coho chum pink sockeye steelhead cutthroat trout
Types of data used to identify ESUs Reproductive isolation –genetic variation –geography –tagging data Evolutionary legacy –life history and morphological variation –environmental and ecology features –degree of genetic differentiation
Example: genetic data chinook status review: available at
Example: life history data chinook status review: available at
Example: distribution data Coho status review: s/tm24/tm24.htm
Example of environmental data Coho status review:
Results for 4 species: coho steelhead chumchinook ESUs listed
Some criticisms of the policy... (summarized from Waples 1995: AFS Symposium 17) Defining distinct populations under the ESA is legal/policy decision, not a biological one (Rohlf 1994) Response: The ESA is about avoiding extinction, which is a biological process
Some criticisms of the policy... The ESA states talks about esthetic, recreational, educational, and historical values, but the ESU policy does not take these into account Response: Good reasons for conservation in general, not necessarily good for determining which units to conserve. Values change; extinction is forever.
Some criticisms of the policy... The ESUs are too small, and do not contain enough variation or abundance for viability (Mundy et al. 1995) Response: ESU evaluations based on inferences about historical levels of isolation on evolutionary time scales. Most ESUs contain many populations and considerable life history variation.
Some criticisms of the policy... The ESU concept is too subjective. Other ESU concepts can be applied more objectively. Response: Professional judgement is required to weigh widely varying data. Any strictly objective criteria would themselves be arbitrary and subjectively drawn.
Continuing controversies... Hatchery fish and the ESA Anadromous/resident fish issues Images from University of Washington image bank
Hatcheries and ESA Interim policy on artificial propagation: Federal Register, Vol. 58, No. 63, April 5, 1993, p ESU status and recovery will be based on natural fish Hatcheries can be used as conservation tool Hatchery fish can be part of an ESU Hatchery stocks will only be listed if essential for recovery
"NMFS' proposed policy refuses to include all the salmon in order to keep ESA counts artificially low and the listing validated. It is time to end the environmental hysterics fueled by junk science at the heart of these salmon listings"
Alsea Valley Alliance v. Evans, 2001 U.S. Dist. LEXIS (D. Ore.) (Sept. 10, 2001). Sept 10, Judge Hogan sets aside Oregon coast coho listing Ruled that NMFS erred in hatchery policy: ESA does not allow listing of parts of an ESU Listing reestablished pending appeal by environmental group NMFS reevaluating its hatchery policy
Resident trout issues In areas of overlap, resident and anadromous trout are genetically similar and are considered part of same ESU River A River B R A R A R A R A observed not observed
Listing decisions have been based on status of anadromous parts of ESU only source: Kostow (ODFW) 2003
Summary Over 10 years of ESA activity resulting in identification of ~50 ESUs and listing of ~25 ESA leaves a lot of discretion to agency on how to implement law Decisions subject to a lot of biological and legal scrutiny, and biology and law do not always mix well Ultimate success -- recovery -- still in future