Threadfin shad

{{Short description|Species of fish}} {{Speciesbox | image = Dorosoma petenense.jpeg | status = LC | status_system = IUCN3.1 | status_ref=<ref name="IUCN">{{cite iucn|author1=NatureServe|author2=Vega-Cendejas, M.|name-list-style=amp|year=2019|title=''Dorosoma petenense''|article-number=e.T191211A102895028|doi=10.2305/IUCN.UK.2019-2.RLTS.T191211A102895028.en|access-date=3 December 2023}}</ref> | taxon = Dorosoma petenense | authority = (Günther, 1867) |synonyms=*''Chatoessus mexicanus'' Günther, 1868 *''Dorosoma petenense'' subsp. ''vanhyningi'' (Weed, 1925) *''Meletta petenensis'' Günther, 1867 *''Signalosa atchafalayae'' Evermann & Kendall, 1898 *''Signalosa atchafalayae'' subsp. ''vanhyningi'' Weed, 1925 *''Signalosa mexicana'' Günther, 1868 *''Signalosa mexicana'' subsp. ''campi'' Weed, 1925 |synonyms_ref=<ref name="Günther">{{GBIF|taxon=''Dorosoma petenense'' (Günther, 1867)|id=2413553|access-date=3 December 2023}}</ref> }}

The '''threadfin shad''' ('''''Dorosoma petenense''''') is a small pelagic freshwater forage fish common in lakes, large streams and reservoirs of the Southeastern United States. Like the American gizzard shad, the threadfin shad has an elongated dorsal fin, but unlike the gizzard shad, its mouth is more terminal without a projecting upper jaw. The fins of threadfin shad often have a yellowish color, especially the caudal fin. The back is grey to blue with a dark spot on the shoulder. ''D. petenense'' is more often found in moving water, and is rarely found deep in the water column. It occurs in large schools, sometimes with gizzard shad, and can be seen on the surface at dawn and dusk. The threadfin shad may reach lengths of {{cvt|8|in|abbr=on}}, but only rarely. This fish is very sensitive to changes in temperature and dissolved oxygen, and die-offs are frequent in late summer and fall, especially when water temperature drops to 42 °F. The threadfin shad is a favorite food for many game fishes, including striped bass, largemouth bass, smallmouth bass, and catfish. This fish is widely introduced throughout the United States as a forage for game fish.

==Description== Adult shad grow to a maximum size of {{convert|7|-|8|in|cm}}, but most specimens are about {{convert|1|in|cm}} long.<ref name="ref1"/><ref name="ref4"/> They have yellowish fins.<ref name="ref4"/>

==Geographic distribution== The threadfin shad is native to the U.S., west of the eastern Appalachian Mountains, through the Mississippi basin all along the Gulf of Mexico down to Belize. This species tends to do best in large lakes and rivers. The construction of dams has created more reservoirs, providing more water bodies for the shad to inhabit. This has expanded the home range of the fish, as has the rise in temperatures in northern lakes.<ref name="ref3">Green, B. W., et al. (2010). [https://www.ars.usda.gov/research/publications/publication/?seqNo115=224888 Threadfin shad impacts phytoplankton and zooplankton community structures in channel catfish ponds.] ''Aquaculture Research'' 41:e524-e536.</ref>

Threadfin shad have been introduced outside of their original as a supplemental forage.<ref name="ref4"/> Populations have become established on the American West Coast from Oregon south to San Diego Bay and the Gulf of California.<ref name="Günther"/>

==Ecology== The threadfin lives a pelagic life in natural lakes, reservoirs, and large streams.<ref name="IUCN"/><ref name="ref1"/> In addition to freshwater habitats, it also inhabits brackish waters such as estuaries and lagoons. It prefers areas with limited vegetation. It is found to a depth of {{convert|50|m|ft}}, and moves between deep water during the day and shallow areas at night.<ref name="IUCN"/>

The young and adults feed on a variety of planktonic organisms and organic debris. Many researchers believe{{citation needed|date=September 2019}} that threadfin shad often compete for plankton with young-of-the-year predator species, especially largemouth bass.<ref name="ref4">Higginbotham, B. [http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-1864/SRAC-140.pdf Forage Species: Range, Description, and Life History.] Oklahoma State University. Oklahoma Cooperative Extension Service.</ref> Threadfin shad is a very important food source for many game fish such as the largemouth bass. It has little known competition, but one species known to have a similar lifestyle is the gizzard shad (''Dorosoma cepedianum'').<ref name="ref1">{{cite book|first1=Maurice F.|last1=Mettee|first2=Patrick E.|last2=O'Neill|first3=J. Malcolm|last3=Pierson|title=Fishes of Alabama and the Mobile Basin|location=Birmingham, Alabama|publisher=Oxmoor House, Inc.|year=1996|isbn=0848714857}}{{page needed|date=May 2014}}</ref>

==Life history== The shad spawns in the spring when the water temperature is in the upper 60s (°F).<ref name="ref2">{{cite journal |last1=Schmitz |first1=Eugene H. |first2=Claude D. |last2=Baker |year=1969 |title=Digestive anatomy of the gizzard shad, ''Dorosoma cepedianum'', and the threadfin shad, ''D. petenense'' |journal=Journal of Transactions of the American Microscopical Society |volume=88 |issue=4 |pages=525–46 |doi=10.2307/3224247 |jstor=3224247}}</ref> Threadfin shad are a pelagic (open water) schooling species that is typically found in large numbers. The shad spawn occurs in the spring and early summer with a secondary spawn often occurring in the early fall. Spawning usually occurs early in the morning on available vegetation. The eggs adhere to submerged and floating objects. Females lay from 2,000 to 24,000 eggs. The young reach reproductive adulthood at one year of age. Life expectancy seldom exceeds 2 to 3 years.<ref name="ref4"/>

==Current management== Many populations of threadfin shad have been introduced by humans to the far north, resulting in large die-offs in the winter when water temperatures fall below 42 °F. This die-off affects both humans and wildlife. A tide of dead fish floats ashore, creating a strong odor unpleasant to humans. The die-off also gives some bird species an unnatural feeding habit, as well. The species should not be transplanted into water bodies that drop below 42 °F.<ref name="ref5">{{cite journal |last1=Green |first1=Bartholomew |last2=Perschbacher |first2=Peter |last3=Ludwig |first3=Gerald |year=2009 |title=Effect of Using Threadfin Shad as Forage for Channel Catfish Fed Daily or Every Third Day |journal=North American Journal of Aquaculture |volume=71 |issue=1 |pages=46–51 |doi=10.1577/A07-098.1|bibcode=2009NAJA...71...46G |url=https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=3466&context=usdaarsfacpub |url-access=subscription }}</ref><ref name=john>{{cite journal |last1=Johnson |first1=James E. |year=1971 |title=Maturity and Fecundity of Threadfin Shad, Dorosoma petenense (Günther), in Central Arizona Reservoirs |journal=Transactions of the American Fisheries Society |volume=100 |issue=1 |pages=74–85 |doi=10.1577/1548-8659(1971)100<74:MAFOTS>2.0.CO;2|bibcode=1971TrAFS.100...74J }}</ref> This species is not endangered and has relatively healthy populations.

==References== {{Commons category|Dorosoma petenense}} {{Reflist}}

Category:Dorosoma Category:Fish of North America Category:Fish described in 1867 Category:Taxa named by Albert Günther Category:Freshwater fish of North America