Climate change vulnerability of native and alien freshwater fishes of California: A systematic assessment approach

PLOS | May 22nd, 2013

Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a

Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a systematic assessment approach that incorporates expert knowledge was developed to determine status and future vulnerability to climate change of freshwater fishes in California, USA. The method uses expert knowledge, supported by literature reviews of status and biology of the fishes, to score ten metrics for both (1) current status of each species (baseline vulnerability to extinction) and (2) likely future impacts of climate change (vulnerability to extinction). Baseline and climate change vulnerability scores were derived for 121 native and 43 alien fish species. The two scores were highly correlated and were concordant among different scorers. Native species had both greater baseline and greater climate change vulnerability than did alien species. Fifty percent of California’s native fish fauna was assessed as having critical or high baseline vulnerability to extinction whereas all alien species were classified as being less or least vulnerable. For vulnerability to climate change, 82% of native species were classified as highly vulnerable, compared with only 19% for aliens. Predicted climate change effects on freshwater environments will dramatically change the fish fauna of California. Most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction. Fishes requiring cold water (,22uC) are particularly likely to go extinct. In contrast, most alien fishes will thrive, with some species increasing in abundance and range. However, a few alien species will likewise be negatively affected through loss of aquatic habitats during severe droughts and physiologically stressful conditions present in most waterways during summer. Our method has high utility for predicting vulnerability to climate change of diverse fish species. It should be useful for setting conservation priorities in many different regions.

Climate-driven aerobic habitat loss in the California Current System

American Association for the Advancement of Science (AAAS) | May 15th, 2020

Climate warming is expected to intensify hypoxia in the California Current System (CCS), threatening its diverse and productive marine ecosystem. We analyzed past region

Climate warming is expected to intensify hypoxia in the California Current System (CCS), threatening its diverse and productive marine ecosystem. We analyzed past regional variability and future changes in the Metabolic Index, a species-specific measure of the environment’s capacity to meet temperature-dependent organismal oxygen demand. Across the traits of diverse animals, exhibits strong seasonal to interdecadal variations throughout the CCS, implying that resident species already experience large fluctuations in available aerobic habitat. For a key CCS species, northern anchovy, the long-term biogeographic distribution and decadal fluctuations in abundance are both highly coherent with aerobic habitat volume. Ocean warming and oxygen loss by 2100 are projected to decrease below critical levels in 30 to 50% of anchovies’ present range, including complete loss of aerobic habitat—and thus likely extirpation—from the southern CCS. Aerobic habitat loss will vary widely across the traits of CCS taxa, disrupting ecological interactions throughout the region.

Climate-Smart Tools to Protect California’s Freshwater Biodiversity

Public Policy Institute of California (PPIC) | May 28th, 2024

California’s freshwater ecosystems—and the native plants and animals that rely on them—have been in decline for decades. Roughly half of California’s native fresh

California’s freshwater ecosystems—and the native plants and animals that rely on them—have been in decline for decades. Roughly half of California’s native freshwater species are highly vulnerable to extinction within this century. But efforts to protect and recover native species now face an additional serious threat: climate change, which is accelerating and compounding the impacts of past and current land and water management issues. Simply working harder, using the same insufficient approaches to conservation, is unlikely to be successful. New approaches, including some that are experimental or highly controversial, are urgently needed. Although California has recently made important strides in setting goals for salmon, the state lacks a comprehensive approach to protecting native biodiversity in the face of climate change. We have identified a portfolio of actions that can help California rise to this urgent challenge.

Climatic regulation of the neurotoxin domoic acid

National Academy of Sciences (NAS) | January 9th, 2017

Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers a

Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers and wildlife in coastal regions worldwide. Evidence of climatic regulation of domoic acid in shellfish over the past 20 y in the Northern California Current regime is shown. The timing of elevated domoic acid is strongly related to warm phases of the Pacific Decadal Oscillation and the Oceanic Niño Index, an indicator of El Niño events. Ocean conditions in the northeast Pacific that are associated with warm phases of these indices, including changes in prevailing currents and advection of anomalously warm water masses onto the continental shelf, are hypothesized to contribute to increases in this toxin. We present an applied domoic acid risk assessment model for the US West Coast based on combined climatic and local variables. Evidence of regional- to basin-scale controls on domoic acid has not previously been presented. Our findings have implications in coastal zones worldwide that are affected by this toxin and are particularly relevant given the increased frequency of anomalously warm ocean conditions.

Collateral Damage: A citizen’s guide to fish kills and habitat degradation at the state and federal water project pumps in the Delta

Bay Institute | March 1st, 2012

Large-scale fish kills and habitat destruction aren’t an unusual occurrence at the giant federal and state pumps that export water from the Sacramento-San Joaquin Delta

Large-scale fish kills and habitat destruction aren’t an unusual occurrence at the giant federal and state pumps that export water from the Sacramento-San Joaquin Delta to agribusinesses and cities in the southern half of the state. These events are business as usual. • Every day, between 870 and 61,000 fish – including from 200 to 42,000 native and endangered fishes – are “salvaged” at the pumps. Most die in the process. • On average, over 9 million fish – representing the twenty fish species considered in this report – are “salvaged” each year at the pumps. As many as 15 million fish of all species encountered are “salvaged” each year. • Up to 40% of the total population of the endangered delta smelt and 15% of the endangered winter-run population of Chinook salmon are killed at the pumps in some years. In the first half of 2011, over 8.6 million splittail were salvaged. • Salvage estimates drastically underestimate the problem. The numbers do not factor in the results of “indirect” mortality, as high levels of export pumping disrupt fish migration, shrink the amount of non-lethal habitat available to fish species, and remove vast amounts of biomass, including fish eggs and larvae too small to be screened at the pumps. • Export pumping causes the lower San Joaquin River to flow backwards most of the year and removes the equivalent of 170 railroad boxcars of water – and the accompanying fish, other organisms, and nutrients – from the Delta ecosystem every minute. • Large numbers of fish being entrained is a problem even for species that are not currently listed as “endangered.” Killing large numbers of fish year after year cuts off population growth in response to favorable conditions and can start the species on a downward path to extinction. As the species declines, the population impacts of entrainment become proportionately larger. • Entrainment is a real problem. But the same interests in the Delta export community who claim that it isn’t also back constructing expensive new conveyance facilities such as a peripheral canal or tunnel to solve the problem that they say doesn’t exist.

Comments of San Francisco Baykeeper et al re: Draft Staff Report on Sacramento/Delta Updates

San Francisco Baykeeper | January 19th, 2024

In the face of a growing and severe ecological crisis, the Board has spent the better part of two decades crafting updates to the Bay-Delta Plan to reasonably protect fi

In the face of a growing and severe ecological crisis, the Board has spent the better part of two decades crafting updates to the Bay-Delta Plan to reasonably protect fish and wildlife beneficial uses. These delayed and too often meager efforts have so far done nothing to reverse the catastrophic path we are on, despite the potential permanent loss of these beneficial uses. The Draft Staff Report’s proposed project and the Voluntary Agreement alternatives will not change our course.

Comments on and Protest of Temporary Urgency Change Petition Regarding Delta Water Quality

California State Water Resources Control Board (SWRCB) | February 17th, 2023

Committee for Delta Resources Improvement Working Paper Regarding the Sacramento-San Joaquin Delta/San Francisco Bay Estuary

Committee for Delta Resources Improvement | December 1st, 1986

Comparing and integrating fish surveys in the San Francisco Estuary: Why diverse long-term surveys are important

UnIversity of California, Davis (UC Davis) | June 30th, 2020

Compliance with D-1641 San Joaquin River October Flow Requirements

California State Water Resources Control Board (SWRCB) | October 9th, 2023