At the Council’s June 12, 2009 request, the ISRP began a review of the Shoshone-Bannock Tribes’ Columbia River Fish Accord proposal titled Salmon River Basin Nutrient Enhancement (2008-904-00). The proposed project seeks to partially mitigate for the dramatic decline of anadromous salmonids (and the associated reduction of available marine-derived nutrients to freshwater spawning and rearing habitat) by experimentally enriching nutrient limited upper Salmon River subbasin streams with carbon, nitrogen, and phosphorus using salmon carcass analogs.
On June 30, the ISRP released it preliminary review (ISRP 2009-26) finding that the research proposed could be of significant benefit to the development of salmon restoration plans for the Columbia Basin. The enhancement of nutrient availability and food web productivity has been widely promoted as an effective restoration strategy, but our understanding of ecosystem-level responses to nutrient addition is limited. This study will provide new information on the utility of salmon carcass analogs as a potential enhancement tool. However, the ISRP requested a response on a number of items. On November 3, the Council forwarded the Shoshone-Bannock Tribes’ point-by-point response to our concerns and a revised project narrative.
ISRP Recommendation: Meets Scientific Review Criteria (Qualified)
The ISRP believes this study will generate important information on this increasingly popular restoration technique. The project proponents responded adequately to most of the comments provided by the ISRP. However, some of the changes in the revised proposal were not described in enough detail for a scientific review. The ISRP recommends that the following items be considered before implementing the project and addressed by the proponents in future categorical or geographic reviews. No further responses to the ISRP are needed for this review iteration.
Qualification 1: Additional information on some of the methods are needed (see below), and power analysis on the fish response (parr and smolts, and smolts/spawner) should be included to provide some indication of the size of response that will be detectable.
Qualification 2: There is a lack of integration among some of the project components that should be addressed before beginning the study.
a) It remains unclear how the nutrient limitation assessment relates to the salmon carcass analog (SCA) treatments. There seems to be little value to understanding which nutrient is limiting primary production at a site if the only treatment option is the application of SCA. How will the nutrient limitation data inform treatment methodology?
b) The coarse particulate organic matter (CPOM) transport determination (really, leaf litter transport) does not seem to be related to the primary objective of the study, the effect of SCA addition on food web dynamics. The CPOM information would be valuable only if there is some hypothesized link between leaf litter transport rates and the manner in which SCA will impact food web dynamics.