Genetic characteristics of coastal cutthroat trout inhabiting an urban watershed

• Published in: Environmental biology of fishes Vol. 101; no. 5; pp. 799 - 811
• Main Authors: Bohling, Justin H., Whitesel, Timothy A., Brown, Melissa
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.05.2018; Springer Nature B.V
• Subjects: Anadromous species; Animal Systematics/Taxonomy/Biogeography; Aquatic ecosystems; Biomedical and Life Sciences; Conservation areas; Dispersal; Ecosystems; Environment; Fish; Freshwater; Freshwater & Marine Ecology; Freshwater fish; Genetic analysis; Genetic diversity; Genetic structure; Genetic variation; Genotypes; Human influences; Inland water environment; Life Sciences; Metropolitan areas; Microsatellites; Nature Conservation; Oncorhynchus clarkii clarkii; Population genetics; Population number; Population structure; Populations; Rivers; Salmon; Tributaries; Trout; Urban areas; Urban environments; Urban populations; Urban watersheds; Zoology; Willamette River; Metapopulation; Population genetics; Dispersal; Urban ecology
• ISSN: 0378-1909; 1573-5133
• DOI: 10.1007/s10641-018-0739-x

Watersheds in urban areas are often heavily degraded due to human activity, which can have negative impacts on freshwater fishes. Monitoring the genetic characteristics of urban populations can provide insights into the impact of development on aquatic ecosystems. We performed a genetic analysis of coastal cutthroat trout ( Oncorhynchus clarkii clarkii ) inhabiting urban tributaries in Portland, OR. By analyzing nuclear microsatellite genotypes, we were able to assess population structure, genetic diversity, and effective population size for six locations across two tributaries on opposite sides of the Willamette River. Genetic diversity was generally equivalent across all sampling locations, although populations from smaller tributaries higher in the stream network had lower levels. Levels of effective population size were low but within expected ranges for small salmonid populations. As anticipated, smaller populations had higher levels of inter-individual relatedness. The primary genetic structure divided populations on opposite sides of the Willamette River, although there was evidence of dispersal between the two groups. Our results suggest that cutthroat trout inhabiting metropolitan areas are not necessarily genetically impoverished and may exhibit characteristics typical of populations in more ‘natural’ environments. Understanding how fish, especially anadromous species, respond to urban environments is essential to evaluating the value of these areas for conservation planning.