The Effects of Salmon Fisheries on Southern Resident Killer Whales

National Marine Fisheries Service (NMFS) | November 30th, 2012

The Endangered Species Act (ESA) and Claims of Property Rights “Takings”

Congressional Research Service (CRS) | January 7th, 2013

The federal Endangered Species Act (ESA) has long been one of the major flash points in debates over government interference with property rights. This report outlines th

The federal Endangered Species Act (ESA) has long been one of the major flash points in debates over government interference with property rights. This report outlines the ESA provisions most relevant to the act’s impacts on private property and surveys the major ESA-relevant principles of Fifth Amendment takings law. The Takings Clause of the Fifth Amendment promises “just compensation” when government actions “take” property. The report then summarizes the court decisions on whether particular government actions (or inaction) based on the ESA “take” private property under the Fifth Amendment. The cases to date address several kinds of ESA impacts on private property: (1) restrictions on land uses that might adversely affect species listed as endangered or threatened, and mitigation conditions to offset the impacts of development; (2) administrative delays; (3) reductions in water delivery or allowable water diversion to preserve lake levels or instream flows needed by listed fish (currently the most active area of ESA takings litigation); (4) restrictions on the defensive measures a property owner may take to protect his/her property from listed animals; and (5) restrictions on commercial dealings in listed species. To date, only one of the 18 ESA-based takings cases disclosed by research, Tulare Lake Basin Water Storage District v. United States, has found a taking. However, two cases, Casitas Municipal Water District v. United States and Klamath Irrigation District v. United States, have yet to be finally resolved and may or may not result in holdings that takings occurred.

The Influence of Zooplankton Availability on Delta Smelt Condition and Foraging Across Habitat Contexts

Publisher not available | December 19th, 2025

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dep

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dependent effects can help optimize and target management efforts. In this analysis, we investigate how environmental and food-web conditions interactively affect condition and foraging of Delta Smelt (Hypomesus transpacificus), an endangered fish endemic to the San Francisco Estuary (the estuary). Food limitation, in terms of pelagic zooplankton availability, is considered a main factor that contributes to the decline in Delta Smelt abundance. Our overarching objective was to examine whether the effect of zooplankton on Delta Smelt depended on habitat context. Specifically, we hypothesized that zooplankton would less positively effect Delta Smelt condition—as measured by hepatosomatic index (HSI)—and foraging success in areas with nearby tidal wetlands, because these adjacent habitats may provide access to prey items from the epibenthos and fringing vegetation. In contrast, in regions with limited proximity to wetlands, we hypothesized that Delta Smelt would rely more on pelagic prey, which would manifest as a more positive effect of zooplankton on body condition and foraging success for Delta Smelt. Using models that accounted for habitat in multiple ways, we found little evidence that zooplankton and habitat interactively influenced Delta Smelt condition or gut fullness. Rather, the influence of zooplankton on HSI and gut fullness was generally positive across habitat contexts. Given the well-documented food limitation in the estuary, promoting the availability of pelagic zooplankton is a rational, albeit complex, management aim. Furthermore, our results suggest that efforts to increase zooplankton would broadly benefit Delta Smelt across a wide range of habitat contexts.

The San Francisco Bay-Delta Agreement: Principles for Agreement on Bay-Delta Standards Between the State of California and the Federal Government

California State Water Resources Control Board (SWRCB) | December 15th, 1994

The Science Charade in Species Conservation

Supreme Court Economic Review | September 2nd, 2017

The Endangered Species Act (ESA) is among the nation’s most important and powerful environmental laws. It is also a source of great conflict and controversy.  The list

The Endangered Species Act (ESA) is among the nation’s most important and powerful environmental laws. It is also a source of great conflict and controversy.  The listing of individual species, the designation of critical habitat and the implementation of conservation measures often prompt fierce legal and political battles. In these conflicts, activists on all sides claim that “sound science” supports their respective positions, and scoff at the “junk science” relied upon by the other side. The U.S. Fish & Wildlife Service fails to rely upon the best science, critics claim.  If it did, they charge, it would adopt policies more to their liking.  The debate over the use of science under the ESA is part of the “science charade” that clouds substantive policy debate about species conservation.3 What typically divides competing interest groups is not a devotion to science, but sharply divergent policy preferences dressed up in scientific garb. The political debate over the use of science under the ESA tends to obscure the dividing line between science and policy and undermines the development of more effective and equitable conservation strategies. Further, efforts to reform the ESA by mandating additional scientific procedures or increasing judicial scrutiny of the use of science by federal agencies will do little to address the ESA’s underlying problems or make species conservation efforts more effective.  Scientific research is necessary to inform species conservation decisions. But species conservation is not – and cannot be – a wholly scientific exercise. Judgments about what constitutes a distinct species or how to evaluate incomplete scientific data necessarily draw upon normative premises. More significantly, policy decisions about what sorts of conservation measures should be adopted are not scientific at all. Whether habitat loss will reduce the likelihood that a given species or population will survive in the wild may be a scientific question, but what measures should be adopted to conserve such habitat, and at what cost, is a normative policy judgment. Science can – indeed, must – inform such inquiries, but science cannot tell us what to do. Engaging in the “science charade,” either by pretending that ESA implementation may be guided by scientific judgment alone or by claiming that reforms of how science is used is unlikely to improve species conservation. To the contrary, efforts to constrain or control the use of science in ESA listing decisions or enhance judicial review of agency scientific determinations will undermine the quality and reliability of ESA science and lead to less effective conservation policy.  Whatever ails the ESA, a failure to incorporate adequate science is not the cause of the disease. As this Article explains, efforts to augment the amount or type of science used in ESA decision-making, whether through additional procedural mandates or altered standards of judicial review, will not address the conflicts that afflict species conservation policy. In some cases, such measures could further undermine the ESA’s ability to conserve species.  Part I of the Article gives a brief overview of the ESA, its operation, and the scientific requirements written into the Act. Part II describes the “science charade,” through which policymakers and others pretend that policy judgments are purely scientific questions, and the legal and political incentives that ensure this artifice persists. Part III details how the ESA’s structure generates political pressure on the use of science and encourages the science charade in species conservation. Part IV explains why various “sound science” reforms will not address these problems, and Part V outlines alternative policy reforms. 

The Scientist and Engineer in Court

American Geophysical Union (AGU) | January 1st, 1983

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 8. The gavel goes down, the witness is called and sworn in: "Will y

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 8. The gavel goes down, the witness is called and sworn in: "Will you tell the truth, the whole truth, and nothing but the truth, so help you God?" Every court day scientists and engineers take this oath, yet few know the duties of an expert witness and fewer still know the procedures in a lawsuit. Unprepared for the courtroom, they watch a drama unfold without benefit of the plot (Ball, 1975). Courtrooms swirl with costume and ceremony. Jury, judge, and spectators assume roles: audience, director, trier of the facts. And the lawyers! Lawyers are the key dramatis personae. Protagonist and antagonist confront one another as lawyers argue their clients cases in the courtroom. They object endlessly. They cross-examine opposing witnesses mercilessly. They speak an opaque jargon of "laches," "remittitur" and "stare decisis." They speak Latin: "ab initio," "in pari causa," "lex loci actus." They speak old French: "estoppel," "fee simple," "voire dire." And they speak law-speak: "abuse of discretion," "clearly erroneous," "malice aforethought" (Mellinkoff, 1963). They call contrary versions of the same story true. They plead for understanding and compassion. They mix independent variables called "facts" and a dependent variable called "law" into an argumentative gruel for court consumption. Then it's over, and the judge delivers his or her opinion. One lawyer calls it the decision of the decade, a magnificent example of benign, reasoned law. The other darkly threatens to appeal all the way to the Supreme Court, if necessary, to relieve an onerous and oppressive injustice. All of this is fascinating theatre, but to the unprepared scientist or engineer, the drama has none of the charm and all of the clarity of a Japanese "Noh" play.

The Status of Rainbow Trout (Oncorhynchus mykiss) in the Stanislaus River Summary report of 2015 snorkel surveys

Delta Stewardship Council (Delta Council) | August 1st, 2016

The Use of Smolt Survival Estimates to Quantify the Effects of Habitat Changes on Salmonid Stocks in the Sacramento-San Joaquin Rivers, California

Canada Department of Fisheries and Oceans (DFO) | July 1st, 1989

Thermal performance in juvenile hatchery Oncorhynchus tshawytscha: aerobic scope tests over a range of environmental temperatures

U.S. Environmental Protection Agency (EPA) | March 15th, 2016

In heavily-altered ecosystems, anthropogenic factors coupled with global climate change have drastically changed available habitats for many native fishes (Cloe

In heavily-altered ecosystems, anthropogenic factors coupled with global climate change have drastically changed available habitats for many native fishes (Cloern and Jassby 2012, Moyle et al. 2013). Water projects such as large hydropower dams have altered flow and temperature regimes (Poff et al. 1997, Bunn and Arthington 2002, Marchetti and Moyle 2001), and reduced or degraded native spawning and rearing habitats (Sheer and Steel 2006, Pelicice and Agostinho 2008), while global climate change has resulted in warmer overall river temperatures (Cloern and Jassby, 2012). As ecologically relevant environmental variables like temperature have shifted, fish populations have subsequently declined (Cloern and Jassby, 2012; Hanak et al., 2015). Native California fishes have been disproportionately affected by these changes, and precipitous population declines have been observed for several species, some of which are listed under the Endangered Species Act (ESA) (Moyle et al. 2013). Despite documented correlations between fish declines and changes in environmental variables such as temperatur e (Moyle and Leidy, 1992; Moyle et al. 2010; Quiñones and Moyle 2014), there has been a profound lack of data available on the actual physiological and/or behavioral mechanisms driving fish population declines. Physiological performance data, such as information on aerobic scope, may help provide mechanistic explanations for both how and why fish population declines are occurring. Furthermore, as populations decline and management becomes more crucial for population persistence, thermal limits, optimal thermal ranges, and data on how key physiological processes, such as metabolic rate, change in response to environmental variables becomes more important. Therefore, the objectives of our study were to quantify the aerobic scope of juvenile Chinook salmon ( Oncorhynchus tshawytscha) acclimated to two different rearing temperatures (14 or 20 °C) and tested over a temperature range of 12-26°C.

Towards the Protection, Restoration, and Enhancement of the Delta Ecosystem: A Synthesis. Appendix A: Summary of Existing Habitat and Species-Specific Plans, Strategies, and Management Approaches

Delta Stewardship Council (Delta Council) | March 15th, 2018