delta smelt
Hypomesus transpacificus McAllister, 1963
Accepted species in Catalogue of Life’s 11 September 2026 base release. This preserves the source classification and available supporting data; it is not a completed species monograph.
Open encyclopedia reference
The delta smelt (Hypomesus transpacificus) is an endangered 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). It functions as an indicator species for the overall health of the Delta's ecosystem. Delta Smelt are usually found at temperatures of less than 25 °C and prefer temperatures of around 20 °C. They are euryhaline but occur mostly at salinities of 0–7 practical salinity units. Because of its one-year lifecycle and relatively low fecundity, it is very susceptible to changes in the environmental conditions of its native habitat. It is listed as a federally threatened species under the Endangered Species Act of 1973.
Wikipedia contributors, Delta smelt; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T02:54:06.457969+00:00. This reference remains separate from the taxonomic record.
Identity & source status
- Scientific name
- Hypomesus transpacificus McAllister, 1963
- Name authority
- McAllister, 1963
- Common name
- delta smelt
- Rank
- species
- Accepted status
- accepted
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Teleostei
- Order
- Osmeriformes
- Family
- Osmeridae
- Genus
- Hypomesus
- Extinction status
- Not supplied by this source
Source habitat flags: Marine: no · Freshwater: yes · Terrestrial: no. These do not form a complete habitat description.
Classification family tree
Nested taxonomic groups from the source. This is not a direct-ancestor chain, a dated evolutionary tree or a phylogenetic reconstruction.
- domainEukaryota (Chatton, 1925) Whittaker & Margulis, 1978
- kingdomAnimalia
- phylumChordata
- subphylumVertebrata
- infraphylumGnathostomata
- parvphylumOsteichthyes
- gigaclassActinopterygii
- superclassActinopteri
- classTeleostei
- orderOsmeriformes
- suborderOsmeroidei
- familyOsmeridae Regan, 1913
- genusHypomesus Gill, 1862
- speciesHypomesus transpacificus McAllister, 1963
Close classified relatives
These entries share the source’s genus, Hypomesus. They are not necessarily the closest relatives established by molecular evidence.
| Species | Classification | Source status |
|---|---|---|
| Japanese smeltHypomesus nipponensis McAllister, 1963 | OsmeridaeChordata | Accepted speciesExtinction status not supplied |
| surf smeltHypomesus pretiosus (Girard, 1854) | OsmeridaeChordata | Accepted speciesExtinction status not supplied |
| Shishamo marine smeltHypomesus japonicus (Brevoort, 1856) | OsmeridaeChordata | Accepted speciesExtinction status not supplied |
| osmeridae pond smeltHypomesus olidus (Pallas, 1814) | OsmeridaeChordata | Accepted speciesExtinction status not supplied |
Names & synonyms
Names explicitly linked to this accepted taxon in the source. Synonymy can change with revision.
| Recorded name | Source status |
|---|---|
| Hypomesus transpacificus transpacificus McAllister, 1963 McAllister, 1963 | synonym |
Source literature & publication evidence
References attached to this source record, including nomenclatural citations where supplied. This is a selected bibliography; abbreviated citations remain in the source’s form.
- McAlliter, D. E. (1963). A revision of the smelt family, Osmeridae. Biological Series, No. 71. Bulletin. National Museum of Canada No. 191: 1–53. Source fields: Taxon.tsv dwc:namePublishedIn, Taxon.tsv dcterms:references
Origins, evidence & remaining research
Name authority and publication references document nomenclature where the source supplies it. They do not establish evolutionary origins or the earliest fossil occurrence.
Specimen-level evidence, morphology, ecological research, phylogenetic studies, a comprehensive bibliography and a located literary passage have not yet been compiled for this record. A suitable sourced image remains to be added.
Dataset citation & attribution
This exact taxon in ChecklistBank · Catalogue of Life 2026-09-11
Catalogue of Life 2026-09-11; dataset 316321; doi:10.48580/dgz5n. https://creativecommons.org/licenses/by/4.0/ . Retrieved 5 October 2026.
Stable key: col:3NXDF. Classification follows source parent identifiers. English common names may vary by region.