The Tui chub (Siphateles bicolor)[1] is a cyprinid fish native to western North America. Widespread in many areas, it is a highly adaptable fish that has historically been a staple food source for native peoples.
The Tui Chub's 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.[2] It is also found in the Pit River and Goose Lake of the upper Central Valley, California.
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. 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.[3] 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.[4]
Tui chubs are found in a variety of habitats, including small, fast-flowing streams, meandering rivers, springs, ponds, and lakes.[5] 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.
Tui chub diet is varied; young fish eat mostly invertebrates, adding plant material and especially algae as they mature. Diet also varies by location and available food sources. 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.[6]
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.[7] The female scatters her eggs randomly over a wide area, where they are then fertilized by several males. Eggs hatch between three and six days later; 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.[8] Females reach sexual maturity at two years old while males reach it at one.[9] Tui chubs are considered old once they surpass seven years and the oldest ever recorded was 33.[10]
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.[11] 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.[12] 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.[13] 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.[14]
The exact number of subspecies is not known; Sigler & Sigler estimate as high as 16. Agreed subspecies include: