Common name: Delta Smelt
available through www.itis.gov
Identification: Moyle (1976); Page and Burr (1991).
Size: 20 cm.
Native Range: Endemic to Sacramento-San Joaquin delta region of central California (Page and Burr 1991).
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Hypomesus transpacificus are found here.
Table last updated 9/24/2021
† Populations may not be currently present.
Ecology: Delta Smelt are small, euryhaline fish primarily occuring in shallow, low-salinity regions of the San Francisco Estuary. Delta Smelt are planktivorous, primarily feeding on planktonic crustaceans. Spawning takes place in spring to early summer in sloughs of the upper estuary (Moyle 2002).
Means of Introduction: Intentionally stocked as forage (Sigler and Sigler 1987).
Status: Extirpated by 1996 (Sigler and Sigler 1996).
Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.
References: (click for full references)
Moyle, P.B. 1976. Inland fishes of California. University of California Press, Berkeley, CA.
Moyle, P.B. 2002. Inland fishes of California. 2nd edition. University of California Press, Berkeley, CA.
Page, L.M., and B.M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. The Peterson Field Guide Series, volume 42. Houghton Mifflin Company, Boston, MA.
Sigler, W.F., and J.W. Sigler. 1987. Fishes of the Great Basin: a natural history. University of Nevad Press, Reno, NV.
Sigler, W.F., and J.W. Sigler. 1996. Fishes of Utah: a natural history. University of Utah Press, Salt Lake City, UT.
Pam Fuller, and Matt Neilson
Revision Date: 12/2/2011
Peer Review Date: 12/2/2011
Pam Fuller, and Matt Neilson, 2021, Hypomesus transpacificus McAllister, 1963: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=795, Revision Date: 12/2/2011, Peer Review Date: 12/2/2011, Access Date: 9/24/2021
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.