Executive Summary
In a recent letter from the Northwest Power and Conservation Council (hereinafter the Council) to the Independent Science Advisory Board (ISAB), the Council posed two questions to be reviewed by economists.
The first question is:
What information is needed to assess the economic impacts to natural resources in the Basin should Northern Pike spread throughout the anadromous and non-anadromous zones? If such information exists, can you estimate the economic impacts of the spread of Northern Pike?
Estimating the economic costs of the spread of Northern Pike (Esox Lucius) (hereinafter NP) throughout the Columbia River Basin (CRB) would involve a large-scale, ecological-economic modeling exercise. Such a study is beyond the scope of this report. Instead, we describe the scope of economic and ecological modeling that would be necessary to estimate the range of possible medium- and long-run consequences of an expanded NP invasion according to best practices for economic analysis. The main points from our review include:
- Evaluating the consequences of an expanded NP invasion would require understanding multiple potential outcomes of interactions among species once NP spread to the anadromous zones and currently uninvaded non-anadromous zones of the CRB.
- Parallel to (and integrated with) the ecological research required, a social science research effort would be needed to estimate the social and individual behavioral responses to, and the resulting costs arising from, an expanded NP invasion.
- Some useful information is available now or may be obtained/estimated in the near-term (e.g., potential costs associated with modifying hydro-operations, activity that may potentially be used to partially compensate for a net increase in predation on native species of concern).
- A fully-developed model integrating biological and socioeconomic processes will also focus on quantifying uncertainty, including uncertainty over how the population dynamics in the model will influence estimated costs over time.
The second question from the Council to be reviewed by economists is:
For the related ISAB question regarding level of Northern Pike suppression needed (question 5, above), can you calculate the costs associated with that?
Here “question 5” refers to the following question for ISAB:
In consideration of ISRP 2018-3 regarding Northern Pike, do we know what level of suppression (exploitation) through gill net removal, angler removal or other methods is needed to reduce the population in Lake Roosevelt to a level sufficient to reduce risk of emigration from the lake or risk to other focal management species?
In a recent report (ISAB 2019), the ISAB responded to question 5. ISAB was unable to determine either:
- The level of Lake Roosevelt northern pike suppression "sufficient to reduce risk of emigration from the lake"; or
- The level of Lake Roosevelt northern pike suppression "sufficient to reduce [...] risk to other focal management species"
Given that ISAB is unable to provide the quantitative targets requested by the Council, we approach the second economic question by describing the information needed to produce a cost estimate for a hypothetical management program that meets best practices for economic analysis. Our observations include:
- A multi-species spatial population model for Lake Roosevelt (LR) that includes NP and NP prey species is required to estimate long-term costs of suppression.
- Some costs may be drawn from recent LR suppression effort and planning. However, these are not adequate to provide a useful upper or lower bound on the range of expected costs of suppression in LR.
- Monitoring and research are likely to remain components of NP suppression in LR. Both activities should be included in an overall cost estimate.
Our hope is that this report will be read as an invitation for investment in interdisciplinary research on human-natural systems in the CRB, and in particular the economics and ecology of invasive species control. Substantial evidence suggests that NP may prove to be a costly invader in the CRB that is unlikely to be eradicated. Unfortunately, it is also unlikely to be the last harmful aquatic invader introduced to the region. Investment in quantitative decision support tools now, with input from economists and natural scientists, may facilitate rapid assessment and informed prioritization of management resources in the future.
Lastly, we do not attempt to draw conclusions regarding the economic merits of any particular method of suppression or level of funding for NP management in the CRB.
