Independent Panel Supports Fish Agency Science

Ann HaydenAnn Hayden is a Senior Water Resource Analyst at EDF.

This recent independent review of the USFWS Biological Opinion (BO) for Delta smelt is worth a read. The study seems largely to have been released under the radar, and we only just became aware of it.

In general, the panel concluded that the science underpinning the BO is sound and credible. The review, requested by the Family Farm Alliance through the Information Quality Act, was completed in October by a panel of five independent scientists. It presents the panel’s responses to questions posed by FFA on the validity of the science of the BO’s Effects Analysis.

The panel addressed the following issues:

1. Export pumps and Delta smelt population—when asked if entrainment of Delta smelt at the pumps drives the smelt population, the panel responded that “entrainment-related mortality may account for a substantial proportion of the population in some years, thus supporting a contention that pumping may have an important ‘sporadic’ effect on delta smelt abundance, particularly during the past decade.”

2. Export pumps and the control of how water flows in the Delta—when asked if project operations control the hydrodynamics of the Delta, the panel concluded “project pumping is the primary force acting on the hydrodynamics of the Delta, based on the fact that the net flow direction has changed since the initiation of pumping. The direction of flow across the Delta is radically changed since project pumping induces Sacramento River flow to be directed toward the southwest to the pumps.”

3. The question of best available scientific data and Delta smelt impacts—when asked if the USFWS’s assertion that project operations exacerbate impacts on smelt is based on the best available scientific data, the panel responded that this “seems reasonable based on the findings and observations of numerous researchers in the Delta who have related shifts in habitat quantity (e.g., information on X2) and quality (e.g., food supply) to aspects of pumping operations. Intuitively, hydrodynamics define estuaries and drive many estuarine processes.”

4. Salinity as an indicator of Delta smelt habitat—when asked if the location of X2 (Delta salinity gradient) is scientifically defensible for identifying suitable Delta smelt habitat availability, the panel responded that they strongly concur with the USFWS’s use of X2 as an index for identifying Delta smelt abiotic habitat. The X2 index is extremely well supported as scientifically valid.”

We do agree with the panel that other factors affecting fish need to be addressed, such as the effects of invasive species and ammonia discharges from upstream sewage treatment plants. We are committed to continuing to work with water export agencies and others in the development of the Bay-Delta Conservation Plan as a way to comprehensively address all the stressors in the Delta to sustainably restore species.

The questions posed to this panel are likely to be similar to those soon to be answered by the National Academy of Science in its upcoming and highly publicized review of both the smelt and salmon Biological Opinions. At this stage, these findings confirm the significant impacts that pumping has had on fish in the Delta and the need for the BO’s to provide mitigation and keep species from the brink of extinction.