200714100 - Bull Trout Effective Population Size in Isolated Populations

Sponsor: Columbia River Fisheries Program Office

Budgets: FY07: $302,000 | FY08: $238,000 | FY09: $253,000

Short description: Estimate population abundance, effective population size and within/among population genetic variability in isolated populations to provide empirical data toward defining minimum viable population size and restoration and recovery of bull trout.

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Final Council recommendation (Nov 2006)

Funding category: Expense

Recommended budgets: FY07: $0 | FY08: $0 | FY09: $0


ISRP final recommendation: Not fundable


The authors attempt to develop an approach for a very restricted area that will have broad applicability throughout the basin; however, it is not clear how results obtained in this study will necessarily have broad applicability in the basin. The project will only describe movement and habitats in a limited area. Making the larger, region-wide inference that these habitats and movements are requirements for bull trout does not seem justified. The sponsors do not demonstrate how their data will be used to infer what bull trout requirements are. It is not clear that management has many options to act on the information gained to make substantial improvements in bull trout recovery. It is not clear what will be done differently based on the information gained. The effective population sizes of 50 to prevent inbreeding and 500 for long-term sustainability are commonly used in the literature, but are not established theoretically or empirically in conservation biology. The minimum genetically effective population sizes for short and long-term persistence remain speculative. Sponsors indicate that the goal of the work is to provide empirical data toward defining minimum viable population objectives for restoration and recovery of bull trout. The task is to estimate effective population size from demographic and genetic data. The step from these estimates to making the decision on defining minimum population sizes is inadequate. The second step, using management tools to address increasing effective population size in populations where it would be deemed too low is absent from the background. The detail on evaluating bull trout movements is adequate, but the detail on determining the abundance of bull trout is not adequate. Several alternative methods are identified but none has yet been selected. No criteria are given for how this selection will take place. Preliminary fieldwork should have been performed so this could have been addressed in this proposal. No purpose is identified for evaluating within and between genetic variability for this project. What is the purpose of these estimates? What will they be used for? More information is needed on the methods to estimate effective population size. Particularly, how will a standardized variance in reproductive success be estimated? In the habitat analysis - how will a weak and strong bull trout population be defined? Is a habitat comparison between the locations where strong and weak populations found really a valid method to determine habitat requirements? This proposal has a need for a map of the study area in order to describe the potential problems created for the bull trout populations by the irrigation canal and to help the reader follow the study design. This is evident throughout the proposal.

State/province recommendation: Not fundable

Review group: OSPIT - Blue Mountain

Recommended budgets: FY07: (n/a) | FY08: (n/a) | FY09: (n/a)