FWS rejects petition to list Longfin smelt population in Sacramento Delta
74 Fed. Reg. 16169 / Vol. 74, No. 67 / Thursday, April 9, 2009 / DEPARTMENT OF THE INTERIOR / Fish and Wildlife Service / 50 CFR Part 17 / Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List the San Francisco Bay-Delta Population of the Longfin Smelt (Spirinchus thaleichthys) as Endangered / Notice of 12–month petition finding.
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 12–month finding on a petition to list the San Francisco Bay-Delta population of the longfin smelt (Spirinchus thaleichthys) as endangered with critical habitat under the Endangered Species Act of 1973, as amended (Act). After a thorough review of all available scientific and commercial information, we find that the San Francisco Bay-Delta population of the longfin smelt does not meet our definition of a distinct population segment (DPS), as identified in our DPS policy (61 FR 4721, February 7, 1996). As a result, listing the species as a DPS is not warranted. However, we are initiating a status assessment of the longfin smelt, and we solicit information on the status of the species range wide.
The longfin smelt is a euryhaline (tolerant of variable salinities) pelagic (lives in open water) fish that inhabits various depths of the water column depending on the individual’s life stage. The historical and current range of the longfin smelt is from Alaska southward to the San Francisco Bay-Delta in California. According to the California Department of Fish and Game, the species is affected by regional water management, and an overall effect of high freshwater outflow through the Delta appears to be an increase in the amount and quality of nursery habitat, increased feeding opportunities, and reduced mortality for the longfin smelt.
KEITHINKING: After a very preliminary review of the petition to list the longfin smelt, FWS found that listing may be warranted. See May 2008 ESAblawg. Here, upon further review, FWS concluded that listing was not warranted, and more information was needed for the species, rangewide. In considering whether the longfin smelt populations in the Delta were a distinct population segment, FWS analyzed two major factors.
First, the DPS analysis considers whether the population is discrete, focusing on geographic isolation. (For example, Central Park squirrels are a discrete population.) FWS found that the longfin smelt populations in the Delta were not discrete because it is likely that they be able to swim elsewhere in the Pacific. In reaching this conclusion, FWS rejected the conflicted published opinion of University of California professor Peter B. Moyle, and FWS also acknowledged that “The distance that longfin smelt could swim or be transported from the San Francisco Bay-Delta is unknown.”
Second, the DPS analysis considers whether the population is significant, often focusing on genetics and morphology. (Central Park squirrels are not genetically or morphologically significant -- yet?) FWS concluded that “There is also no indication that longfin smelt differ morphologically between the San Francisco Bay-Delta population and other populations… Additional study should provide more information on the distribution of genetic variation within the species and determine if longfin smelt from different locations are intermixing.” However, FWS also recognized that “Because of its distinctive characteristics, the San Francisco Bay-Delta population of longfin smelt was once described as a species separate from more northern populations. (Moyle 2002, p. 235).”
In contrast, under state law, the California Department of Fish & Game recommended that Longfin smelt be classified as “threatened” and that additional protections were needed. As noted in prior ESAblawg postings, the Delta smelt is a huge source of ESA related conflicts with regional water managers, and the listing of the longfin smelt would further complicate problems for the Central Valley Project and State Water Project in the Sacramento region.
Yup. We're thinking the same thing. More litigation coming soon.
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Distinct Population Segment Analysis… Discreteness… Summary of Geographic Isolation... Although no physical barriers exist between the San Francisco Bay-Delta and estuarine habitat to the north, the distance that longfin smelt are able to travel out into the open ocean or northward along the coast to reach these areas is unknown… Based on the recent information that a portion of the San Francisco Bay-Delta population of longfin smelt are anadromous and able to swim into and out of the San Francisco Bay-Delta, it is likely that individuals have the ability to swim into and out of ocean currents and into and between estuaries, including estuaries outside of the San Francisco Bay-Delta estuary… therefore, Moyle’s (2002, p. 235) conclusion that longfin smelt in the San Francisco Bay-Delta being reproductively isolated is questionable.
Genetic Separation. Stanley et al. (1995, p. 395) found the San Francisco Bay-Delta population and Lake Washington populations of longfin smelt were significantly different in allele frequencies at several loci (gene locations). However, the authors also stated the overall genetic dissimilarity was within the range of other conspecific fish species (Stanley et al. 1995, p. 395) and concluded their research indicates longfin smelt from Lake Washington and the San Francisco Bay-Delta are conspecific (of the same species) despite the large geographic separation. We believe that this study is not well suited to address whether the San Francisco Bay-Delta longfin smelt population is markedly separated from other populations of longfin smelt (the criterion of the DPS policy) because only two locations were sampled. These two locations are ecologically different from one another and widely separated geographically.