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About the Species



Delta smelt

 

The delta smelt (Hypomesus transpacificus) is an endangered[1][2] slender-bodied smelt, about 5 to 7 cm (2.0 to 2.8 in) long, in the family Osmeridae. Endemic to the upper Sacramento-San Joaquin Estuary of California, it mainly inhabits the freshwater-saltwater mixing zone of the estuary, except during its spawning season, when it migrates upstream to fresh water following winter "first flush" flow events (around March to May).[3] It functions as an indicator species for the overall health of the Delta's ecosystem.[4] 

Because of its one-year lifecycle and relatively low fecundity, it is very susceptible to changes in the environmental conditions of its native habitat.[5] Efforts to protect the endangered fish from further decline have  focused on limiting or modifying the large-scale pumping activities of  state and federal water projects at the southern end of the estuary,  thereby limiting water available to farming. However, these efforts have  not prevented the species from becoming functionally extinct in the  wild.[6] 


Taxonomy and evolution

The delta smelt is one of five currently recognized species within the genus Hypomesus, which is part of the larger smelt family, Osmeridae. The abbreviated distribution of Hypomesus species along  both the east and west sides of the Pacific Ocean suggests that their  common ancestor had a range that would have crossed the Pacific.  Researchers have hypothesized that climatic changes may have reduced the  range of the ancestral species during cooling periods, which would have  created a reproductive barrier, allowing speciation to occur.[7] Although the low number of species in the genus and high levels of homoplasy have frustrated attempts to determine whether the northern Pacific H. olidus or H. nipponensis are the basal species of Hypomesus,[7] the most recent speciation event in Hypomesus is known to have been between the two native east Pacific species, H. pretiosus and H. transpacificus.  This is plausibly due to a geographic isolation of a widespread eastern  Pacific ancestor, of which some members were isolated in a freshwater  basin in western California, possibly in the lakes that would have been  located in the southern San Joaquin Valley during the Pleistocene epoch.[7] 


Habitat

The delta smelt is endemic to the Sacramento–San Joaquin River Delta in California, where it is distributed from the Suisun Bay upstream through the delta in Contra Costa, Sacramento, San Joaquin, and Solano Counties.  The delta smelt is a pelagic (lives in the open water column away from the bottom) and euryhaline species (tolerant of a wide salinity range). It has been collected from  estuarine waters with salinities up to 14 parts per thousand. 

Historically, delta smelt were distributed from San Pablo Bay  upstream to Sacramento on the Sacramento River and Mossdale on the San  Joaquin River, which varied seasonally and with freshwater outflow.[11] Today, large areas of historic delta smelt habitat and designated  critical habitat have become unsuitable for some life history stages of  the species, though key environmental characteristics (e.g. temperature,  salinity, water depth) of these areas have not changed.[12][13] Delta smelt disappeared from the southern portion of their historic  habitat in the late 1970s, which coincides with substantial increases in  the amounts of water exported from the delta. Water export operations  likely have a great effect on the distribution, abundance, and genetic  diversity of delta smelt.[14] 


Lifecycle

The delta smelt is semelparous,  living one year and dying after its first spawning.  Their spawning  occurs in spring in river channels and tidally influenced backwater  sloughs upstream of the mixing zone where salt water meets fresh water.   The Sacramento and San Joaquin Rivers then transport the delta smelt  larvae downstream to the mixing zone, normally located in the Suisun  Bay.  Young delta smelt then feed and grow in the mixing zone before  starting their upstream spawning migration in late fall or early winter. 

The delta smelt is preyed upon by larger fish, especially striped bass and largemouth bass, which are introduced species in the Sacramento-San Joaquin Delta.[15] 


Endangered status

Historically,  delta smelt were relatively abundant in the upper Sacramento-San  Joaquin Estuary, with populations declining dramatically in the 1980s.[16] They were listed as threatened by both federal and state governments in  1993, and sustained record-low abundance indices, prompted their  listing as endangered under the California Endangered Species Act in  2010.[17][18] Critical habitat was listed for delta smelt on December 19, 1994.[19] 

Delta smelt are threatened with extinction due to anthropogenic  alterations to their ecosystem, including urbanization, non-native  species, water diversions, contaminants, and the conversion of complex  tidal habitats to leveed channels.[20] A survey in April 2015 found only one individual delta smelt. Although  the fish is almost extinct in the wild,  extant populations remain in a  captive-breeding program at UC Davis and in a fish hatchery operated by the U.S. Fish and Wildlife Service near Shasta Dam.[6] 


Court protection

In 2005, the U.S. Fish and Wildlife Service (FWS) issued a biological opinion that the Central Valley Project and the California State Water Project were not having an adverse effect on the recovery of the delta smelt.[21]  The Natural Resources Defense Council sued, and in 2007, Fresno U.S. District Court Judge Oliver Wanger found the biological opinion  was arbitrary and capricious and ordered protections for the delta smelt while the document was redone.[22] 

In 2008, at the close of the court's deadline, the FWS issued a new biological opinion.[23] This time, the FWS came to the opposite of its earlier conclusion,  finding the water projects were jeopardizing the continued existence of  the delta smelt.[24]  When six new plaintiffs sued, Judge Wanger preliminarily ordered the  FWS to give him weekly justifications of delta flow restrictions and  appointed four scientists as his own expert witnesses.[25]  After haranguing FWS expert witnesses as “zealots”,[26] in December 2010 Judge Wanger, again, found the FWS BioOp was arbitrary  and capricious and, again, ordered the FWS to complete a new one.[27] 

In 2014, a divided panel of the Ninth Circuit Court of Appeals reversed Judge Wanger.[28]  While the new biological opinion  was “a ponderous, chaotic document,  overwhelming in size”, it was found not arbitrary and capricious.[29]  The Ninth Circuit affirmed that the water projects were jeopardizing the existence of the delta smelt, and given TVA v. Hill's command that endangered species must be saved "whatever the cost", Circuit Judge Jay Bybee opined that California could only use the smelts' water after receiving an exemption from the God Squad.[30]  In January 2015 the U.S. Supreme Court declined review without comment.[31] 

The smelt is unpopular among farmers, with a common complaint  being that 200,000 acres of farmland have been left fallow due to "four  buckets of minnows".[32]  Although allegations have been made that this protection has hurt  California's agricultural sector, with the devastation of hundreds of  thousands of acres of farmland and the loss of tens of thousands of jobs  in the Central Valley,[33] a 2009 UC Davis study estimated that job losses due to smelt protection were closer to 5,000.[34] An additional 16,000 job losses in the Central Valley were attributed to the drought California had been experiencing in recent years.[citation needed]


References

  • NatureServe (2014). "Hypomesus transpacificus". IUCN Red List of Threatened Species. 2014. Retrieved 24 Aug 2016.{{cite iucn}}: error: malformed |id= identifier (help) Listed as Critically Endangered (CR A2bce ver 3.1) 
  • "Delta Smelt". U.S. Fish & Wildlife Service. 2013. Retrieved 6 February 2014. 
  • Sommer,  T. et al. 2011. The spawning migration of delta smelt in the Upper San  Francisco Estuary. San Francisco Estuary and Watershed Science: 9(2). 
  • "Delta Smelt". Center for Biological Diversity. Retrieved 10 May 2015. 
  • Moyle, PB. 2002. Inland fishes of California. University of California Press, Berkeley. 
  • Krieger, Lisa M. (15 April 2015). "California drought: Delta smelt survey finds a single fish, heightening debate over water supply". San Jose Mercury News. Retrieved 9 May 2015. 
  • Evolutionary and biogeographical patterns within the smelt genus Hypomesus in the North Pacific Ocean. Journal of Biogeography. 2008;35:48–64. doi:10.1111/j.1365-2699.2007.01782.x. 
  • McAllister DE.  A revision of the smelt family, Osmeridae. National Museum of Canada Bulletin. 1963;191:29–31. 
  • Sweetnam DA.  Field identification of delta smelt and wakasagi. Interagency Ecological Program for the Sacramento-San Joaquin Estuary Newsletter. 1995;(Spring):1–3. 
  • Molecular resolution of the systematics of a problematic group of  fishes (Teleostei: Osmeridae) and evidence for morphological homoplasy. Molecular Phylogenetics and Evolution. 2009;50:163–178. doi:10.1016/j.ympev.2008.10.021. PMID 19015040. 
  • Radtke,  LD (1966) Distribution of smelt, juvenile sturgeon and starry flounder  in the Sacramento-San Joaquin Delta. In: Fish bulletin. California  Department of Fish and Game, Sacramento, pp 115–129 
  • CDFG  (2003) Comment letter on the five-year status review of the delta  smelt. California Department of Fish and Game, California, p 6 
  • Miller J, Swanson C, Poole KS (2006) Emergency petition to list the delta smelt (Hypomesus transpacificus)  as an endangered species under the Endangered Species Act. Center for  Biological Diversity, Bay Institute, & Natural Resources Defense  Council. 
  • Bennett,  WA (2005) Critical assessment of the delta smelt population in the San  Francisco Estuary, California. San Francisco Estuary Watershed Sci 3:1–71. 
  • Raymond Bark; Brent Bridges; Dr. Mark D. Bowen (2008). "2008 Tracy Research Study: Plan Predator Impacts on Salvage Rates of Juvenile Chinook salmon and Delta Smelt". Archived from the original on June 29, 2010. Retrieved 2009-06-26. 
  • Newman  KB (2008) Sample design-based methodology for estimating delta smelt  abundance. San Francisco Estuary Watershed Sci 6:1–18. 
  • CDFG  (2010) State & federally listed endangered & threatened animals  of California. California Department of Fish & Game,State of  California, The Natural Resources Agency, California. 
  • Federal Register 58:12863; March 5, 1993 
  • Federal Register 59:65256 
  • Nichols FH, Cloern JE, Luoma SN, Peterson DH (1986) The modification of an estuary. Science 231:567–573. 
  • "Federal Judge Throws Out Biological Opinion for Threatened Delta Smelt". 2007-05-25. 
  • Natural Resources Defense Council v. Kempthorne, 506 F. Supp. 2d 322 (E.D. Cal. 2007). 
  • http://www.fws.gov/sfbaydelta/cvp-swp/cvp-swp.cfm 
  • Jenkins, Matt (10 December 2010). "California's Tangled Water Politics". High Country News. 42 (22). Retrieved 22 May 2015. 
  • "The Consolidated Delta Smelt Cases | California Water Law Journal". 
  • "Judge's comments in Delta smelt case raised eyebrows". 2011-09-28. 
  • San Luis & Delta-Mendota Water Auth. v. Salazar, 760 F. Supp. 2d 855, 863 (E.D. Cal. 2010). 
  • http://www.pacificlegal.org/releases/10-1-14-Stewart-and-Jasper-1-1347 citing San Luis & Delta-Mendota Water Authority v. Jewell, 747 F.3d 581 (9th Cir. 2014). 
  • Id., see oral argument video at [1]. 
  • San Luis & Delta-Mendota Water Authority v. Jewell, 747 F.3d 581 (9th Cir. 2014) citing Eric M. Yuknis, Note, Would a “God Squad” Exemption under the Endangered Species Act Solve the California Water Crisis?, 38 B.C. Envtl. Aff. L. Rev. 567 (2011). 
  • "State Water Contractors v. Jewell". 
  • Cooke, Charles C. W. (27 January 2014). "Green Drought, For the sake of the smelt, California farmland lies fallow". The National Review. Retrieved 22 May 2015. 
  • ABC KFSN-TV "Water Shortage in the Central Valley" 

  1. Howitt, R., Josue Medellin-Azuara, Duncan MacEwan. "Measuring  the Employment Impact of Water Reductions" Department of Agriculture  and Resource Economics and Center for Watershed Sciences, UC Davis,  September 2009 


External links

  • The State Water Project

        San Francisco Bay watershed 

  • Hydrography
  • Ecology
  • List of tributaries
  • List of lakes


Subdivisions 

Major San Francisco Bay Suisun Bay San Pablo Bay Minor Golden Gate Grizzly Bay Richardson Bay San Rafael Bay Richmond Inner Harbor San Leandro Bay Former Yerba Buena Cove Mission Bay Waterways Rivers San Joaquin Sacramento Napa Guadalupe Petaluma Creeks (discharging into the Bay) Alameda Baxter Cerrito Codornices Coyote (Santa Clara) Coyote (Marin) San Leandro San Lorenzo Schoolhouse Temescal Sausal Redwood San Mateo Sonoma Corte Madera Arroyo Corte Madera del Presidio San Rafael Miller Novato Tolay San Francisquito Pacheco Alhambra Adobe Rodeo Refugio Pinole Garrity Rheem Karlson San Pablo Castro Wildcat Fluvius Innominatus Marin (Alameda County) Strawberry Easton Mission Creek Reservoirs Calaveras Reservoir Lafayette Reservoir Straits and estuaries Clifton Court Forebay Carquinez Strait Oakland Estuary Raccoon Strait Sacramento–San Joaquin River Delta Stockton Deepwater Shipping Channel Watersheds Laguna Creek Watershed Guadalupe watershed 


Parks and protected areas 

  • Don Edwards National Wildlife Refuge
  • San Pablo Bay National Wildlife Refuge
  • Eden Landing Ecological Reserve
  • Hayward Regional Shoreline
  • Hayward Shoreline Interpretive Center
  • Crown Memorial State Beach
  • McLaughlin Eastshore State Park
  • Emeryville Crescent State Marine Reserve
  • Point Isabel Regional Shoreline
  • César Chávez Park
  • Brooks Island Regional Preserve
  • Point Pinole Regional Shoreline
  • Antioch Dunes National Wildlife Refuge
  • Coyote Point Recreation Area
  • Middle Harbor Shoreline Park
  • National Estuarine Research Reserve
  • China Camp State Park
  • San Francisco Maritime National Historical Park
  • SF Bay Trail
  • Oyster Bay Regional Shoreline
  • Big Break Regional Shoreline
  • Palo Alto Baylands Nature Preserve


Major islands Alameda Alcatraz Angel Treasure Island Yerba Buena Minor Brooks Bair Bay Farm Belvedere Brother Castro Rocks Coast Guard Greco Hooks Island Mare Red Rock The Sisters Marin Islands Roe Ryer Seal Islands Peninsulas/infill Albany Bulb Point Isabel Foster City Fleming Point Hunters Point Steamboat Point Potrero Point 


Wetlands 

  • Baylands
  • Chelsea
  • Cordelia
  • Crissy Field
  • Hoffman
  • Meeker
  • Mowry
  • Napa Sonoma
  • Point Molate
  • Salt ponds
  • Seal
  • Stege
  • Suisun
  • Westpoint


Bridges

 San Francisco–Oakland Eastern span replacement Richmond–San Rafael San Mateo–Hayward Dumbarton Golden Gate Benicia–Martinez Antioch Carquinez Leimert Park Street Fruitvale High Street Bay Farm Island Tubes Posey/Webster Street Transbay Ferries 

  • Angel Island–Tiburon Ferry
  • Blue & Gold Fleet
  • Golden Gate Ferry
  • San Francisco Bay Ferry (WETA)


Ports and marinas 

  • Port of San Francisco
  • Port of Oakland
  • Port of Richmond
  • Hunters Point Naval Shipyard
  • Mare Island Naval Shipyard
  • Port of Redwood City
  • Berkeley Marina
  • Oyster Point Marina/Park
  • Clipper Yacht Harbor
  • Westpoint Harbor
  • Foster City Marina (proposed)


Other History

 Delta and Dawn Discovery Site Humphrey the Whale San Leandro Oyster Beds Richmond Shipyards U.S. Army Corps of Engineers Bay Model Harold Gilliam Marincello Ecology Golden Gate Biosphere Reserve Cosco Busan oil spill Thicktail chub 


Environmental organizations

 Conservation and Development Commission The Watershed Project Save The Bay Citizens for East Shore Parks Friends of Five Creeks Urban Creeks Council 1971 oil spill Greenbelt Alliance The Bay Institute Reber Plan San Francisco Baykeeper San Francisco Estuary and Watershed Science Estuary Partnership 


Transportation 

Ridgway's rail/California clapper rail Water Trail Transportation in the San Francisco Bay Area  


Categories: 

  • IUCN Red List critically endangered species
  • Hypomesus
  • Sacramento–San Joaquin River Delta
  • Endemic fauna of California
  • Environmental controversies
  • Fish described in 1963

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