Ocean acidification impairs olfactory discrimination and homing ability of a marine fish

National Academy of Sciences (NAS) | February 2nd, 2009

The persistence of most coastal marine species depends on larvae finding suitable adult habitat at the end of an offshore dispersive stage that can last weeks or

The persistence of most coastal marine species depends on larvae finding suitable adult habitat at the end of an offshore dispersive stage that can last weeks or months. We tested the effects that ocean acidification from elevated levels of atmospheric carbon dioxide (CO2) could have on the ability of larvae to detect olfactory cues from adult habitats. Larval clownfish reared in control sea- water (pH 8.15) discriminated between a range of cues that could help them locate reef habitat and suitable settlement sites. This discriminatory ability was disrupted when larvae were reared in conditions simulating CO2-induced ocean acidification. Larvae be- came strongly attracted to olfactory stimuli they normally avoided when reared at levels of ocean pH that could occur ca. 2100 (pH 7.8) and they no longer responded to any olfactory cues when reared at pH levels (pH 7.6) that might be attained later next century on a business-as-usual carbon-dioxide emissions trajectory. If acidifi- cation continues unabated, the impairment of sensory ability will reduce population sustainability of many marine species, with potentially profound consequences for marine diversity.

Ocean Climate Indicators: A Monitoring Inventory and Plan for Tracking Climate Change in the North-central California Coast and Ocean Region

Gulf of the Farallones National Marine Sanctuary Advisory Council | August 14th, 2014

The impacts of climate change, defined as increasing atmospheric and oceanic carbon dioxide and associated increases in average global temperature and oceanic a

The impacts of climate change, defined as increasing atmospheric and oceanic carbon dioxide and associated increases in average global temperature and oceanic acidity, have been observed both globally and on regional scales, such as in the North-central California coast and ocean, a region that extends from Point Arena to Point Año Nuevo and includes the Pacific coastline of the San Francisco Bay Area. Because of the high economic and ecological value of the region’s marine environment, the Gulf of the Farallones National Marine Sanctuary (GFNMS) and other agencies and organizations have recognized the need to evaluate and plan for climate change impacts.

One-quarter of freshwater fauna threatened with extinction

Nature Portfolio (Springer Nature) | January 8th, 2025

Optimizing the dammed: Water supply losses and fish habitat gains from dam removal in California

Journal of Environmental Management (Elsevier) | April 1st, 2014

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic an

Dams provide water supply, flood protection, and hydropower generation benefits, but also harm native species by altering the natural flow regime and degrading aquatic and riparian habitat. Restoring some rivers reaches to free-flowing conditions may restore substantial environmental benefits, but at some economic cost. This study uses a systems analysis approach to preliminarily evaluate removing rim dams in California's Central Valley to highlight promising habitat and unpromising economic use tradeoffs for water supply and hydropower. CALVIN, an economic-engineering optimization model, is used to evaluate water storage and scarcity from removing dams. A warm and dry climate model for a 30-year period centered at 2085, and a population growth scenario for year 2050 water demands represent future conditions. Tradeoffs between hydropower generation and water scarcity to urban, agricultural, and instream flow requirements were compared with additional river kilometers of habitat accessible to anadromous fish species following dam removal. Results show that existing infrastructure is most beneficial if operated as a system (ignoring many current institutional constraints). Removing all rim dams is not beneficial for California, but a subset of existing dams are potentially promising candidates for removal from an optimized water supply and free-flowing river perspective. Removing individual dams decreases statewide delivered water by 0–2282 million cubic meters and provides access to 0 to 3200 km of salmonid habitat upstream of dams. The method described here can help prioritize dam removal, although more detailed, project-specific studies also are needed. Similarly, improving environmental protection can come at substantially lower economic cost, when evaluated and operated as a system.

Outmigration survival of wild Chinook salmon smolts through the Sacramento River during historic drought and high water conditions

Environmental Biology of Fishes (Springer) | January 27th, 2020

Pacific Coast Federation of Fishermen’s Associations et al v. Wilbur Ross et al

U.S. District Court, Northern District of California | December 12th, 2019

Pacific Salmon and Steelhead Trout: Managing Under the Endangered Species Act

Congressional Research Service (CRS) | November 30th, 2012

Along the Pacific Coast, 28 distinct population segments of Pacific salmon and steelhead trout are listed as either endangered or threatened under the Endangered Species

Along the Pacific Coast, 28 distinct population segments of Pacific salmon and steelhead trout are listed as either endangered or threatened under the Endangered Species Act (ESA), with three additional populations identified as “species of concern.” While no species of anadromous trout or salmon is in danger of near-term extinction, individual population segments within these species have declined substantially or have even been extirpated. The American Fisheries Society considers at least 214 Pacific Coast anadromous fish populations to be “at risk,” while at least 106 other historically abundant populations have already become extinct. Human activities—logging, grazing, mining, agriculture, urban development, and consumptive water use—can degrade aquatic habitat. Silt can cover streambed gravel, smothering fish eggs. Poorly constructed roads often increase siltation in streams where adult salmon spawn and young salmon rear. Removal of stream-side trees and shade frequently leads to higher water temperatures. Grazing cattle remove stream-side vegetation and exacerbate stream bank erosion. Urbanization typically brings stream channelization and filled wetlands, altering food supplies and nursery habitat. Habitat alterations can lead to increased salmonid predation by marine mammals, birds, and other fish. Dams for hydropower, flood control, and irrigation substantially alter aquatic habitat and can have significant impacts on anadromous fish. In addition, natural phenomena stress fish populations and contribute to their variable abundance. Current management efforts aim to restore the abundance of ESA-listed native northeast Pacific salmonids to historic, sustainable population levels. The National Marine Fisheries Service (NMFS, also popularly referred to as “NOAA Fisheries”) in the Department of Commerce implements the ESA for anadromous salmonids. When a federal activity may harm an ESA-listed salmonid, the ESA requires the federal agency to consult with NMFS to determine whether the activity is likely to jeopardize the survival and recovery of the species or adversely modify its critical habitat. Prior to the listing of salmonid “evolutionarily significant units” (ESUs) under the ESA, the Northwest Power and Conservation Council took the lead in the Columbia River Basin under the 1980 Pacific Northwest Electric Power Planning and Conservation Act, by attempting to protect salmon and their habitat while also providing inexpensive electric power to the region. Under this effort, federal agencies and public utilities have spent hundreds of millions of dollars on technical improvements for dams, habitat enhancement, and water purchases to improve salmon survival. Recent years have seen an increased interest by state governments and tribal councils in developing comprehensive salmon management efforts. This report summarizes the reasons for ESA listings and outlines efforts to protect ESA-listed species.

Passage and Flow Considered Anew: Wild Salmon Restoration Via Hyrdo Relicensing

University of Montana | May 24th, 2016

Patterns in the use of a restored California floodplain by native and alien fishes

University of California, Davis (UC Davis) | July 7th, 2007

Fishes were sampled on the restored floodplain of the Cosumnes River in Central California in order to determine patterns of floodplain use. The floodplain was sampled fo

Fishes were sampled on the restored floodplain of the Cosumnes River in Central California in order to determine patterns of floodplain use. The floodplain was sampled for seven years (1998-2002, 2004-2005) during the winter-spring flooding season. The fishes fell into five groups: (1) floodplain spawners, (2) river spawners, (3) floodplain foragers, (4) floodplain pond fishes, and (5) inadvertent users. Eight of the 18 abundant species were natives, while the rest were aliens. There was a consistent pattern of floodplain use, modified by timing and extent of flooding. The first fishes to appear were floodplain foragers, inadvertent users, and juvenile Chinook salmon (river spawners). Next were floodplain spawners, principally Sacramento splittail and common carp. At the end of the season, in ponds of residual water, non-native annual fishes, mainly inland silverside and western mosquitofish, became abundant. Adult spawners left when inflow decreased; their juveniles persisted as long as flood pulses kept water levels up and temperatures low. Juvenile splittail and carp quickly grew large enough to dominate floodplain fish samples, along with smaller numbers of juvenile Sacramento sucker and pikeminnow (river spawners). Such juveniles left the Relatively few fishes that used the floodplain for spawning or rearing became stranded, except late season alien fishes. Most alien fishes had resident populations in adjacent river, sloughs, and ditches and were not dependent on the floodplain for persistence. This indicates that Central Valley floodplains managed to favor native fishes should have the following characteristics: (1) extensive early season flooding, (2) complete drainage by the end of the flooding season, (3) few areas with permanent water, (4) a mosaic of physical habitats, (5) regular annual flooding but with high variability in flood regime.

Patterns of Freshwater Species Richness, Endemism, and Vulnerability in California

PLOS | July 6th, 2015