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Presentation TitleEstimating spatial dynamics and population abundance of upper Fraser watershed fluvial bull trout (Salvelinus confluentus).
Presenting Author NameRachel Chudnow
Presenting Author AffiliationUniversity of British Columbia
Presenting Author EmailEmail hidden; Javascript is required.
Presentation Number6
Unit MeetingWestern Division/WA-BC Chapter
SymposiumThe future of Bull Trout conservation and management across Its range
General TopicSalmonids, freshwater, movement modelling, telemetry
Type of PresentationOral

Effective management of bull trout’s (Salvelinus confluentus) migratory life histories requires consideration of the spatial dynamics of meta-populations, factors which have significant ramifications for the scale and effectiveness of management actions for a species thought to face a triple threat of vulnerability to exploitation (i.e., adult aggregation, slow growth and late maturity, and aggressive feeding). Spatial information to inform management decision-making is physically difficult to collect as individuals are distributed across large areas. The addition of spatial information in modelling also presents significant trade-offs between inclusion of additional model complexity and the inferences that can be drawn from these analyses. While mark-recapture and telemetry are common field techniques used to assess movement patterns and vital population rates (e.g. abundance and mortality), more complicated models to estimate key population variables are often not applied. Here we develop a multi-state spatial capture-recapture model for fluvial bull trout in the upper Fraser watershed (UFW) of British Columbia. UFW bull trout are key predators on salmon smolts from various nursery lakes and form the basis of an important recreational fishery in the region. Data for this analysis come from a five-year tagging study which employed a combination of mark-recapture, radio telemetry, and genetic assignment data. The analysis will demonstrate this modelling approach’s ability to provide robust estimates of spatial distribution, recapture rates, and population abundance while providing a unique opportunity to further develop this modelling approach for a highly migratory riverine species of conservation concern within a complex, nonlinear stream network. Thus, growing the limited body of research exploring the importance of the UFW to bull trout in the region. Results of this analysis will inform management decision-making for recreational fishing opportunities for the species both within the UFW, as well as through its implications for management of bull trout across the species range.