In response to NOAA Fisheries’ May 5, 2017 request, the Independent Scientific Advisory Board (ISAB) reviewed a report titled Interior Columbia Basin Life-Cycle Modeling (May 23, 2017 draft; LCM report). The life-cycle modeling is part of a proposed adaptive management strategy for evaluating alternative salmonid recovery actions in the Columbia River Basin. The LCM report builds on previous reports, which were reviewed most recently by the ISAB in 2013 (ISAB 2013-5). The report describes ongoing efforts to model the numerous factors affecting salmon and steelhead in the Columbia River Basin. Life-cycle modeling remains a significant challenge because of the complexity of the wide-ranging life histories of these fish and the many locations where fish are affected by human activities and the changing environment.
The ISAB is impressed with the growth and progress of the life-cycle modeling effort and the inclusion of investigators from several other agencies and organizations. The current LCM report has been expanded to include several areas recommended by the ISAB in earlier reviews, including new chapters describing methods for incorporating habitat variables, potential effects of toxics, and efforts to develop communication with managers. However, several components such as ocean, toxics, and communication are at early stages of development, and as acknowledged by NOAA Fisheries, non-native species are not covered. Because the various components are at differing stages of development, the report would be strengthened by descriptions and supporting illustrations of how the parts will be integrated or interact.
Models are always a tradeoff between realism and simplicity. In particular, many of the models in the LCM report do not include all sources of variation. Consequently, the models can be used for ranking scenarios, but their predicted results may not be accurate. The ISAB believes that going forward the authors of the LCM report need to clearly define scenarios to be tested, describe the assumptions in the model and the implications if those assumptions are incorrect, and provide measures of uncertainty and variability in model output. Additionally, models need to be validated by comparing outputs to real-world data. Many of the models presented in the LCM report rely on long term datasets, which highlights the value of the ongoing monitoring and evaluation needed to parametrize and validate models. Perhaps most important, modelers must provide a timeline for when and how the fully developed model will be ready to address specific management needs. In summary, the ISAB believes that the LCM report would benefit from a “roadmap” for how the life-cycle models will serve policymakers and managers for which they are being developed.
The ISAB acknowledges the technical nature of its review of the LCM report and that the primary audiences are the LCM report authors and recovery and restoration practitioners who will use the model outputs in planning exercises. That said, the individual chapter reviews include sections on model goals and key findings, often thought-provoking, which should be of interest to a broad audience. To help summarize three key aspects of the models, the ISAB created a table (see Executive Summary), which contains the ISAB's collective understanding of 1) species/ESU addressed, 2) key questions asked, and 3) outputs that could be useful to decision makers and managers.