Analyisis of Genetic Variation in the Olympic Mudminnow (Novumbra hubbsi) Final Report

DeHaan, Patrick; Adams, Brice; Hawkins, Denise; Tabor, Roger; Thompson, Brad

The Olympic mudminnow (Novumbra hubbsi) is endemic to western Washington and inhabits wetland areas and low-gradient streams in the Chehalis River Basin, Puget Sound, and along the Olympic Coast. Available habitat has declined substantially and Olympic mudminnow are considered a state sensitive species and an increasing priority for conservation. Although information exists regarding the species life history and distribution, information regarding the status and long-term viability of populations, the boundaries that define populations and conservation units, and the level of gene flow among populations is much more limited. Genetic data has become increasingly useful for conservation planning and could provide important information for Olympic mudminnow; however, limited genetic data currently exists. In this study we developed a suite of microsatellite DNA markers specifically for Olympic mudminnow and we used these markers to genotype over 1,000 individuals collected from 23 locations distributed throughout the species range. We found that the level of genetic variation within collections varied considerably, but overall, most locations did not appear to be at risk of any detrimental effects associated with low genetic variation. We observed the greatest amount of genetic variation with collections from the Chehalis River Basin, which can be atributed to the fact that the Chehalis River was a glacial refugium for Olympic mudminnow. Overall there was a relatively high degree of genetic variation among collections ... and nearly all collection locations represented a genetically distinct population. Exceptions were multiple collections made within the Green Cove and Hopkins Ditch drainages, each of which represented a single population. Genetic relationships among populations appear to have been largely influenced by the glacial history of western Washington and the species limited dispersal ability and history of isolation in coastal areas. Prior to this study, the origins of Olympic mudminnow in eastern Puget Sound (native populations vs. undocumented introductions) were unknown. Our data indicate that these populations represent undocumented introductions of mudminnow from an unknown site or sites on the southern Olympic Coast. Information presented in this study will be useful for informing the conservation planning process for Olympic mudminnow and form the basis for future genetic monitoring efforts.

Analyisis of Genetic Variation in the Olympic Mudminnow (Novumbra hubbsi) Final Report

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