According to the National Marine Fisheries Service (NMFS, NOAA Fisheries) a population must satisfy two criteria to be considered an ESU: (1) it must be substantially reproductively isolated from other conspecific population units; and (2) it must represent an important component in the evolutionary legacy of a species. 69 Fed. Reg. at 31355.
Unfortunately there is no unambiguous scientific yardstick which provides a threshold value for how genetically “unique” or “evolutionarily significant” a population or set of populations must be. Thus, the concept of an ESU can be used to arbitrarily list under the Endangered Species Act (ESA) a population or a set of populations in a relatively small geographic area, even if other populations of the same species or subspecies are thriving. In other words, ESUs allow government agencies to list species under the Endangered Species Act that are not actually threatened or endangered. Biologically it is perfectly natural for populations to expand and contract over time. It is also natural for some populations of a species to disappear while new ones are formed elsewhere. Through the ambiguity of ESUs, federal and state agencies are increasingly taking advantage of the public’s good intentions and/or ignorance to unjustly infringe on private property rights. For instance, by designating an ESU on the margins, or even beyond the margins of a species’s range the government can force people off their land while funneling millions of dollars into phony “restoration” projects. In these areas of naturally incompatible habitat, the species may not survive well for natural reasons that are not the result of “habitat degradation” as is frequently touted. Often politicians, political activists, and un-scientists will compare current population numbers to population trends of recent decades when the species was artificially propagated on a large scale. Listing fish under the ESA usually restricts hatchery operations even more, giving the impression that the species continues to experience a precipitous decline due to worsening “habitat degradation.” Rarely is any empirical evidence of habitat degradation actually given. Government beauracrats and un-scientists seldom visit these areas to verify claims of habitat degradation for themselves, apparently preferring the comfort of their offices. These ESUs are designed to effectively be a permanantly “endangered species.” Never mind that the species as a whole is actually thriving. Once the ESU is listed under the ESA, restoration efforts almost always focus on “habitat restoration” when in fact environmental quality of the area may already be impeccable. Since, by definition, species do not survive well on the margins of their range for natural reasons, listing such an ESU creates an insurmountable burden on taxpayers and especially on local residents. A perfect example of such a situation is the Central California Coast Coho Salmon ESU (see below).
Furthermore, the construct of an ESU may be illegal. According to Russell C. Brooks with the Pacific Legal Foundation:
Congress stated that the purpose of the ESA is
to provide a means whereby the ecosystems upon which endangered species and threatened species depend may be conserved, [and] to provide a program for the conservation of such endangered species and threatened species.
16 V.S.C. § 1531(b).
However, rather than following Congress’s stated ESA purpose, NMFS decided to redefine the ESA purpose as one related to conservation biology. Indeed, NMFS states that “the major goal of the Act is to conserve the genetic diversity of species and the ecosystems they inhabit.” See NOAA Technical Memorandum NMFS F/NWC (Waples 1991). Yet, the phrase “conserving the genetic diversity of a species” is not in the ESA’s language, and NMFS has no authority to change the law where Congress has not expressly allowed it to do so.
As a result of NMFS’s redefinition of the ESA’s purpose, NMFS has violated the ESA’s express terms by creating a new classification of species concerning only Pacific salmon and steelhead – the ESU. Congress was careful to specifically define the “distinct population segment of a species” (DPS) as a population segment that “interbreeds when mature.” 16 U.S.C. § 1532(16). Accordingly, Congress’s definition represents a clear limitation of the population unit that may be considered for listing under the ESA.
However, NMFS’s ESU creation does not comport with Congress’s species definition and, moreover, its salmon and steelhead ESUs contradict internally its own ESU creation. NMFS created the ESU classification in place of Congress’s DPS classification in order to include many more salmon and steelhead populations in its listings. In an effort to expand genetic diversity, NMFS is using its ESU construct to combine noninterbreeding populations with similar genetics and list them as a single unit. (See Waples 1995). For example, the Puget Sound chinook salmon ESU has almost two dozen populations, most of which do not interbreed-underscoring the fallacy of the ESU classification. In sum, if an ESU like the Puget Sound chinook ESU has several individual, genetically similar populations that do not interbreed, then any one population within the ESU is not distinct from another. Thus, a listing of the ESU is clearly unjustified because both of Congress’s “distinct” and “interbreeding” criteria for a DPS are missing.
NMFS’s error is that it made unauthorized changes to essential ESA terms and classifications by mere policy memoranda and applied it to salmon and steelhead populations that plainly do not meet the ESA classification of extinction risk. By law, if NMFS is to list a population under the ESA, it must qualify as a species, subspecies, or distinct population segment of a species. NMFS’s proposed salmon and steel head ESU listings do not meet this requirement. NMFS has created illegal listings of arbitrary salmon and steelhead populations under the ESA simply by redefining its authority to list population units that do not quality as DPSs.