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The Delta Fish Decline: What Does It Mean for Public Policy?

by Mike Connor

Delta pelagic fish populations have been crashing for several decades. Since the millennium, that decline may have taken a turn for the worse, though there is some disagreement among statisticians as to whether the pace of the recent decline is truly worse, or simply statistical noise in the long-term decline of the Delta smelt, striped bass, and longfin smelt. Op-ed commentators have responded to the decline by criticizing CALFED for not being able to resolve this problem after spending untold millions of dollars on research and monitoring, while failing to develop any public agreement on indicators of Delta health and attainable goals that all parties can accept.

This fall has seen two important scientific summaries of the problem: an analysis and work plan developed by the Interagency Ecological Program and a review of that analysis and plan by outside reviewers brought together by the CALFED Science Program. The perspective of the outside reviewers was refreshing-in essence, they were puzzled over why there was such a focus on the trends of the last five years when the system has been declining since the beginning of good data records. This debate about whether the Delta fish crash is getting worse points to an important public policy failing-we do not have a generally understood agreement for what level of Delta fish abundance is attainable, desirable, and acceptable to all parties.

The second important finding of the internal analysis and external review is the extent to which fairly obvious losses of fish-getting stuck on the debris screens (impingement), being collected and transported to other parts of the Delta (salvage), or being sucked into the water supply system (entrainment)-are not well quantified. While the complex biological factors that influence the health of Delta fish populations may never be well understood, the costs of understanding and remediating the effects of fish impingement, salvage, and entrainment seem small compared to the consequences of the multi-billion-dollar water conveyance decisions we are making.

Surprisingly, the analysis found that we don't have very good information about the impingement and entrainment effects of other large Delta water pumping projects, such as the use of cooling water for Bay-Delta power plants. Section 316 of the Clean Water Act requires that cooling water withdrawals and discharges must be protective of local fish populations. In other parts of the country, power plants have been required to use evaporative, air-cooled, and hybrid cooling towers to reduce cooling water use by 95% or more, and fine wedge wire intake screening and/or aquatic filter barriers to prevent fish impingement and to minimize the entrainment of early life stages of fish. These issues have received much less public discussion in the Bay Area. The effects of impingement and entrainment should be relatively easy to understand, quantify, and extrapolate as to their effects on Delta fish populations compared to all of the other subtle ecological threats (e.g., contaminants, nutrients, invasive species) to the Bay. It's time for these assessments to be made, peer reviewed, and presented to the general public.

The California Bay-Delta Authority is charged with determining by 2007 whether the re-routing of water through the Delta is working or whether other solutions are necessary. For such a significant decision, it is surprising how little is known about the framework for making the decision. What ecological functions must be maintained in order for through-Delta transport to be considered a success by all the stakeholders? Are there other criteria for success? What data will be used? What is the process for conducting and reviewing the analysis? It's time for the different CALFED parties to state what their expectations are. Most good decision making requires that the decision criteria be developed before the decision is made. Otherwise, there will naturally be suspicion that the decision was made first, and the criteria adjusted to fit the politics.

Mike Connor is Executive Director of S.F. Estuary Institute.

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