Tui chub

During the Pleistocene, Tui chub lived in the Great Basin’s large pluvial lakes. As time passed, these lakes diminished, and different populations became isolated. {{Cite journal |last1=McClanahan |first1=Lon L. |last2=Feldmeth |first2=C. Robert |last3=Jones |first3=Jeff |last4=Soltz |first4=David L. |date=1986 |title=Energetics, Salinity and Temperature Tolerance in the Mohave Tui Chub, Gila bicolor mohavensis |url=https://www.jstor.org/stable/1444886 |journal=Copeia |volume=1986 |issue=1 |pages=45–52 |doi=10.2307/1444886 |jstor=1444886 |issn=0045-8511|url-access=subscription }} The Tui Chub's modern range includes the Lahontan and Central system of the Great Basin, as well as the Owens, Truckee, Carson, Quinn, Humboldt, Columbia Klamath, and Mojave Rivers.{{Cite journal |last1=Raymond |first1=Anan W. |last2=Sobel |first2=Elizabeth |date=1990 |title=The Use of Tui Chub as Food by Indians of the Western Great Basin |url=https://www.jstor.org/stable/27825400 |journal=Journal of California and Great Basin Anthropology |volume=12 |issue=1 |pages=2–18 |jstor=27825400 |issn=0191-3557}} It is also found in the Pit River and Goose Lake of the upper Central Valley, California. They can have a strong presence where they are found such as in Pyramid Lake where they are the most abundant species of fish present.{{Cite journal |last1=Galat |first1=David L. |last2=Vucinich |first2=Nancy |date=July 1983 |title=Food Partitioning between Young of the Year of Two Sympatric Tui Chub Morphs |url=http://doi.wiley.com/10.1577/1548-8659(1983)1122.0.CO;2 |journal=Transactions of the American Fisheries Society |language=en |volume=112 |issue=4 |pages=486–497 |doi=10.1577/1548-8659(1983)112<486:FPBYOT>2.0.CO;2 |bibcode=1983TrAFS.112..486G |issn=0002-8487|url-access=subscription }}

They have historically been abundant enough in the western Great Basin to provide a valuable food source to native peoples living there.

The range of the Tui chub has been controversial in the past with it being debated where exactly this species is native to. There is strong evidence indicating the species is native to Nevada and southern Oregon. It was once thought to be native to Idaho, but that is no longer considered accurate. Data obtained through natural history and the discovery of Tui chub bones in the Columbia River Basin in Washington provides evidence that the Tui chub is also native to the Columbia River Basin region.{{Cite journal |last1=Lubinski |first1=Patrick M. |last2=Scholz |first2=Allan T. |date=2021-05-21 |title=Tui Chub (Siphateles bicolor) are Native to the Columbia River Basin in Washington State |url=https://bioone.org/journals/northwest-science/volume-94/issue-3-4/046.094.0303/Tui-Chub-Siphateles-bicolor-are-Native-to-the-Columbia-River/10.3955/046.094.0303.full |journal=Northwest Science |volume=94 |issue=3–4 |doi=10.3955/046.094.0303 |issn=0029-344X|url-access=subscription }}

The form and appearance of the Tui chub is variable; many were originally described as different species by J. O. Snyder, but have since been reduced to subspecies. Their body shape comes in two forms: either more slender or more plump.{{Cite journal |last=Kimsey |first=J. B. |date=1954 |title=The life history of the tui chub, Siphateles bicolor (Girard), from Eagle Lake, California |journal=California Fish and Game |volume=40 |issue=4 |pages=395–410}} In general, mature individuals are characterized by a deep olive above and white below, with a smooth variation in shading along the sides, and a brassy reflection. The fish has broad scales and a relatively large head compared to body.{{Cite web |title=California Fish Species - California Fish Website |url=https://calfish.ucdavis.edu/species/?ds=698&uid=78 |access-date=2023-10-24 |website=calfish.ucdavis.edu}} Fins are olive and sometimes tinted with red. The pectoral fins are far forward and low on the body. Length has been recorded at up to 45 centimeters (18 inches); however, 20–25cm is typical for an adult.{{Cite journal |last1=Raymond |first1=Anan W. |last2=Sobel |first2=Elizabeth |date=1990 |title=The Use of Tui Chub as Food by Indians of the Western Great Basin |url=https://www.jstor.org/stable/27825400 |journal=Journal of California and Great Basin Anthropology |volume=12 |issue=1 |pages=2–18 |jstor=27825400 |issn=0191-3557}} They do not display sexual dimorphism, indicating that the females and males look the same.{{Cite journal |last1=Baker |first1=Henry K. |last2=Hankins |first2=Danielle C. |last3=Shurin |first3=Jonathan B. |date=October 2021 |title=Introgressive hybridization erodes morphological divergence between lentic and lotic habitats in an endangered minnow |journal=Ecology and Evolution |language=en |volume=11 |issue=19 |pages=13593–13600 |doi=10.1002/ece3.8086 |issn=2045-7758 |pmc=8495819 |pmid=34646492|bibcode=2021EcoEv..1113593B }}

Tui chubs are found in a variety of habitats, including small, fast-flowing streams, meandering rivers, springs, ponds, and lakes.{{Cite web |title=California Fish Species - California Fish Website |url=https://calfish.ucdavis.edu/species/?ds=698&uid=78 |access-date=2023-10-25 |website=calfish.ucdavis.edu}} Their adaptability allows them to live in both high cold lakes, such as Lake Tahoe, and warmer desert streams. Their optimal range for water temperature lies between 15 and 30°C but they can survive in 2 to 36°C conditions. Although they are suited for wide range of environments, they are typically found in slow water with abundant vegetation.

In lake habitats such as Walker Lake, Tui chub are heavily preyed upon. They are a key prey item for the Lahontan Cutthroat trout in Walker Lake. Additionally, Tui chub are preyed upon by fish-eating birds. {{Cite journal |last=Cooper |first=James J. |date=1985 |title=Age, Growth, and Food Habits of Tui Chub, Gila Bicolor, in Walker Lake, Nevada |url=http://www.jstor.org/stable/41712181 |journal=The Great Basin Naturalist |volume=45 |issue=4 |pages=784–788 |jstor=41712181 |issn=0017-3614}}

Tui chub diet is varied; young fish eat mostly invertebrates, adding plant material and especially algae as they mature. Young fish almost immediately begin feeding.Diet also varies by location and available food sources. For example, in some regions zooplankton are a fundamental and essential food item for maturing Tui chub. These fish can be categorized as opportunistic omnivores in their feeding habits. While zooplankton is essential in juveniles, some subspecies of Tui chub may differ in diet as adults. For example, Siphateles bicolor obesa relies more on eating aquatic macroinvertebrates as they mature compared to the Siphateles bicolor pectinifer which becomes an obligate planktivore in adulthood. Both subspecies mentioned can be found in the same lakes, yet their feeding habits differ. Eating habits can be determined by the fineness of the gill rakers. Fine-rakered forms in Pyramid Lake feed more on plankton in open water, while coarse-rakered forms, which live near the bottom eat more plants and algae. The largest individuals will eat other fish also.{{Cite web |title=California Fish Species - California Fish Website |url=https://calfish.ucdavis.edu/species/?ds=698&uid=78 |access-date=2023-10-25 |website=calfish.ucdavis.edu}} There is evidence of benthic feeding in Tui chub.

Spawning may occur between late April and early August, depending on water temperature. In Pyramid Lake the peak season is June; males move inshore first, then congregate around arriving females in shallow water, preferring areas with a sandy substrate and heavy vegetation.{{Cite web |title=California Fish Species - California Fish Website |url=https://calfish.ucdavis.edu/species/?ds=698&uid=78 |access-date=2023-10-25 |website=calfish.ucdavis.edu}} The female scatters her eggs randomly over a wide area, where they are then fertilized by several males. In some populations, a chub’s first spawning has been reported to occur in the spring of the fish’s third year. During spawning, the Tui chub’s coloration will intensify in both males and females. Eggs hatch between three and six days after fertilization; however, the embryos do not mature uniformly, leading to multiple spawning periods. The hatchlings feed in a pelagic state and grow rapidly in their first summer, attaining lengths of 22 to 42mm. In the subsequent summers they gain 20 to 55mm until they reach a mature adult size of 20 to 40cm.{{Cite journal |last1=Raymond |first1=Anan W. |last2=Sobel |first2=Elizabeth |date=1990 |title=The Use of Tui Chub as Food by Indians of the Western Great Basin |url=https://www.jstor.org/stable/27825400 |journal=Journal of California and Great Basin Anthropology |volume=12 |issue=1 |pages=2–18 |jstor=27825400 |issn=0191-3557}} Females reach sexual maturity at two years old while males reach it at one.{{Cite web |title=ECOS: Species Profile |url=https://ecos.fws.gov/ecp/species/7289 |access-date=2023-10-25 |website=ecos.fws.gov}} Tui chubs are considered old once they surpass seven years and the oldest ever recorded was 33.{{Cite web |title=California Fish Species - California Fish Website |url=https://calfish.ucdavis.edu/species/?ds=698&uid=78 |access-date=2023-10-25 |website=calfish.ucdavis.edu}} In lake habitats, it is common for Tui chub to live between five and six years with fish aged greater than six being more rare.

Archeological evidence reveals that the Tui chub was an important food source for the native people of the Western Great Basin, namely the Northern Paiute. Dip and gill nets were the preferred methods for harvesting fish; however, baited trotlines, basket traps, and weirs were often used for small-scale fishing.{{Cite journal |last=Delacorte |first=Michael G. |date=2015 |title=Some Thoughts on Great Basin Fisheries |url=https://www.jstor.org/stable/45155438 |journal=Journal of California and Great Basin Anthropology |volume=35 |issue=1 |pages=29–51 |jstor=45155438 |issn=0191-3557}} Ethnographic reports indicate that the Northern Paiute fished on a large scale with gill nets. They used tule floats, willow sticks, and stone weights to suspend the unattended nets in shallow water for up to a few days. Tui chub were a staple in the indigenous diet because they are abundant and available year round, especially from April to August. During this 5 month period, the natives were provided with an almost inexhaustible stock. Fresh, small fish were swallowed whole while large fish were filleted.{{Cite journal |last1=Raymond |first1=Anan W. |last2=Sobel |first2=Elizabeth |date=1990 |title=The Use of Tui Chub as Food by Indians of the Western Great Basin |url=https://www.jstor.org/stable/27825400 |journal=Journal of California and Great Basin Anthropology |volume=12 |issue=1 |pages=2–18 |jstor=27825400 |issn=0191-3557}} The remaining fish were dried and stored for later consumption. After examining bone fragments from several caches of fish, researchers determined that the natives had a preference for small chub.{{Cite journal |last=Delacorte |first=Michael G. |date=2015 |title=Some Thoughts on Great Basin Fisheries |url=https://www.jstor.org/stable/45155438 |journal=Journal of California and Great Basin Anthropology |volume=35 |issue=1 |pages=29–51 |jstor=45155438 |issn=0191-3557}} Many speculate that this arose from the desire to acquire calories efficiently. At larger sizes, the bone structure of the Tui Chub makes it difficult to separate edible portions. However, at small sizes, the bones are small enough to be ingested. Through careful observation of the Tui chub's behavior and environment, the tribes of the Western Great Basin were able to capitalize on this vital food source.{{Cite journal |last=Delacorte |first=Michael G. |date=2015 |title=Some Thoughts on Great Basin Fisheries |url=https://www.jstor.org/stable/45155438 |journal=Journal of California and Great Basin Anthropology |volume=35 |issue=1 |pages=29–51 |jstor=45155438 |issn=0191-3557}}

As the pluvial lakes of the Pleistocene diminished over time, Tui chub populations became more isolated. This isolation ultimately led to the formation of many subspecies of Tui chub.

File:Mohave tui chub.jpg

File:Owens Tui Chub.jpg

The exact number of subspecies is not known; Sigler & Sigler estimate as high as 16. It has been claimed by some that almost all Nevada, Oregon, and California isolated drainages contain a distinct subspecies of Tui chub. Agreed subspecies include:

• Siphateles bicolor bicolor
• Siphateles bicolor isolata
• Siphateles bicolor mohavensis
• Siphateles bicolor obesa
• Siphateles bicolor pectinifer
• Siphateles bicolor snyderi

There are various ways in which these many subspecies differ. To tell apart, for example, Siphateles bicolor obesa from Siphateles bicolor pectinifer, one can count the number of gill rakers; this distinguishing factor is more obvious for fish greater than 25 mm in length and is especially clear in Tui chub greater than 50 mm in length. This factor indicates similarity in diets for young Tui chub of both subspecies. Additionally, these subspecies differ in that the Siphateles bicolor pectinifer adults’ mouths are more oblique, and they have more concave head shapes.

In terms of conservation, the Tui chub is in a unique position due to the abundant subspecies mentioned above. The various subspecies may vary in their conservation status. For example, The High Rock Springs tui chub (Gila bicolor ssp) is now considered extinct.{{Cite journal |last1=Jelks |first1=Howard L. |last2=Walsh |first2=Stephen J. |last3=Burkhead |first3=Noel M. |last4=Contreras-Balderas |first4=Salvador |last5=Diaz-Pardo |first5=Edmundo |last6=Hendrickson |first6=Dean A. |last7=Lyons |first7=John |last8=Mandrak |first8=Nicholas E. |last9=McCormick |first9=Frank |last10=Nelson |first10=Joseph S. |last11=Platania |first11=Steven P. |last12=Porter |first12=Brady A. |last13=Renaud |first13=Claude B. |last14=Schmitter-Soto |first14=Juan Jacobo |last15=Taylor |first15=Eric B. |date=August 2008 |title=Conservation Status of Imperiled North American Freshwater and Diadromous Fishes |url=https://afspubs.onlinelibrary.wiley.com/doi/10.1577/1548-8446-33.8.372 |journal=Fisheries |language=en |volume=33 |issue=8 |pages=372–407 |doi=10.1577/1548-8446-33.8.372 |bibcode=2008Fish...33..372J |issn=0363-2415|url-access=subscription }} Other subspecies have had opposing conservation stories, having once been considered extinct but then re-classified; one such case is the Independence Valley Tui Chub.

The conservation status of some of the subspecies above is as follows as of 2008:

• Siphateles bicolor isolata – Endangered
• Siphateles bicolor mohavensis – Endangered
• Siphateles bicolor snyderi – Endangered

One major threat to some subspecies of Tui chub is other subspecies of Tui chub. Introgressive hybridization occurs when there is interbreeding between different species or subspecies; it is a major threat to some species of Tui chub due to it erasing the distinct genetic diversity between populations. A concrete example of this is found in the introgressive hybridization of the Owens Tui Chub (Siphateles bicolor snyderi) and the Lahontan Tui Chub (Siphateles bicolor obesa); breeding and the creation of hybrids with the Lahontan Tui Chub has led to the Owens Tui Chub being categorized as endangered. In these populations, there are intermediate body shapes that reflect this hybridization. The implications of this specific example for the Tui chub species at large indicate less variation for which divergent natural selection is able to act upon.

The subspecies the Mohave Tui chub (Siphateles bicolor mohavenis) also faces the threat of introgressive hybridization, in this case with the arroyo chub(Gila orcutti). This ultimately led to the Mohave Tui chub being eliminated entirely from the Mohave River system. One additional challenge for this species is that relative to other desert living fish, it is not as able to tolerate high temperatures. Its thermal scope is 30 degrees Celsius. They are not able to function in a large thermal range; they are broadly more well-adapted for open water. Mohave Tui chub also are not able to osmoregulate as effectively as other species, leading to a narrow range of salinities it can realistically tolerate. These factors make this endangered subspecies more vulnerable to extinction.

Tui chub conservation is layered in that not only due its many subspecies they have extreme variety in their conservation statuses and stories but also in that Tui chub have also historically been invasive. In Diamond Lake, Oregon, Tui chub’s presence led to a significant decline in water quality and negatively impacted trout populations.{{Cite journal |last1=Eilers |first1=J. M. |last2=Truemper |first2=H. A. |last3=Jackson |first3=L. S. |last4=Eilers |first4=B. J. |last5=Loomis |first5=D. W. |date=September 2011 |title=Eradication of an invasive cyprinid ( Gila bicolor ) to achieve water quality goals in Diamond Lake, Oregon (USA) |url=http://www.tandfonline.com/doi/abs/10.1080/07438141.2011.590269 |journal=Lake and Reservoir Management |language=en |volume=27 |issue=3 |pages=194–204 |doi=10.1080/07438141.2011.590269 |bibcode=2011LRMan..27..194E |issn=1040-2381}} Their impact on trout is that they have a significant overlap in diet, leading to competition between the two species.{{Cite journal |last1=Meeuwig |first1=Michael H. |last2=Bailey |first2=Elizabeth J. |last3=Clements |first3=Shaun P. |last4=Hodgson |first4=Brett L. |date=October 2022 |title=Inferred Trophic Characteristics and Ecological Roles of Native and Nonnative Fishes in Odell Lake, Oregon |url=https://afspubs.onlinelibrary.wiley.com/doi/10.1002/nafm.10822 |journal=North American Journal of Fisheries Management |language=en |volume=42 |issue=5 |pages=1301–1323 |doi=10.1002/nafm.10822 |bibcode=2022NAJFM..42.1301M |issn=0275-5947|url-access=subscription }} Once Tui chub were no longer in Diamond Lake, water quality improved drastically.

{{Reflist}}

• C.M.Hogan, Marc Papineau et al., Development of a dynamic water quality simulation model for the Truckee River, Earth Metrics Inc., Environmental Protection Agency Technology Series Washington D.C. (1987)
• William F. Sigler and John W. Sigler, Fishes of the Great Basin (Reno: University of Nevada Press, 1987), pp. 166–170
• {{FishBase|genus=Siphateles|species=bicolor|year=2006|month=March}}

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Category:Chubs (fish)

Category:Siphateles

Category:Fish described in 1856

Category:Taxa named by Charles Frédéric Girard

Category:Fish of the Western United States

Category:Fish of the Pacific Ocean

Category:Fish of North America

Category:Fauna of the Mojave Desert

Category:Fauna of the Great Basin

Category:Fauna of the Sierra Nevada (United States)