Population Status and Characteristics of Macrhybopsis Gelida, Platygobio gracilis and Rhinichthys cataractae in the Missouri River Basin

<p>Few sturgeon chub (Macrhybopsis gelida: Cyprinidae) have been collected in the last decade, therefore their status, habitat selection and morphology were investigated at 172 previous collection sites. Data on two ecologically similar species, Platygobio gracilis and Rhinichthys cataractae, were also collected. Macrhvbopsis gelida were collected at 28 sites on the Powder River (n = 158) in Wyoming and Montana, and at one site on the Yellowstone River (n = 1) in Montana. Age-I, Age-II and Age-III M. gelida were collected. Specimens were 37 to 95 mm in total length. Macrhvbopsis gelida were ripe in mid-June, at water temperatures of 18.3-22. 2°C, and produced about 5, 000 eggs. Sites where M. gelida were collected in the Powder River typically had flows > 0.35 m/sec and substrates with ≥ 40% gravel/rubble. Percent species composition of M, gelida at riffle sites on the Powder River declined from 28% in 1979-80 to about 3% in 1989-90 . Morphometric characters of M. gelida were similar throughout the Powder River, except for head width, snout length and body depth. Counts of M. gelida anal, dorsal, pelvic and pectoral fin rays; lateral line scales; and scale rows above and below the lateral line were significantly (P ≤ 0.05) different among three sections of the Powder River. No M. gelida x M. aestivalis hybrids were found. Platygobio gracilis (n = 8, 889) and R. cataractae (n = 2,857) were more widely distributed and more abundant than M. gelida and distinct habitat associations were not identified. Morphometric characters of£. Gracilis and R. cataractae with significant (P ≤ 0.05) differences among rivers were: anal and dorsal fin base lengths; pelvic, pectoral and dorsal fin lengths; caudal peduncle depth; eye diameter; head length and width; snout length; and body depth. Platygobio gracilis and R. cataractae from the Little Missouri River in North and South Dakota had longer anal and dorsal fin bases; longer pelvic, pectoral and dorsal fins; longer heads and snouts; and deeper caudal peduncles than specimens from other streams in the Missouri River Basin. Meristic characters of E. gracilis and R. cataractae with significant (P ≤ 0.05) differences among rivers were: anal, dorsal, pelvic and pectoral fin rays; lateral line scales; and scale rows above and below the lateral line. No subspecies of£. gracilis or R. cataractae were identified, however, R. cataractae showed the greatest tendency for subspeciation.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis - Open Access

Discipline thesis:degree_discipline

Wildlife and Fisheries Science

Year

1992

Author dc:creator

• Werdon, Selena J.

Contributors dc:contributor

• Charles R. Berry

• Aquaculture and Fisheries
• Natural Resources and Conservation

Statement dc:rights

• Copyright © 1992 Selena J. Werdon. All rights reserved.

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/600

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-1600