9425 - Laserfiche WebLink

Home Browse Search

'J 1 1 J 1 1 falcate (rays 9[8-10]), originating slightly posterior to the pelvic fins (rays 8-9[7-9]); anal fin strongly falcate with fin rays 9[7-10]; caudal ~duncle slender, but not approaching the pencil-thin narrowness of G. elegans; and, caudal fin (rays 19[19-20]) deeply forked with somewhat rounded lobes. Other physical characteristics include a strongly decurved lateral line (scales 75-85[70- 96]); arobust pharyngeal arch with teeth usually 2, 5-4, 2; gill rakers 11-14 and I2-15 in the l~ and 2'~ arches, respectively; and, vertebrae 46[43-48]. Adults are usually dusky green to bluish gray dorsally and silver to white below, and may grow to 500 mm total length (TL). More commonly, adult roundtail chubs are 200-300 mm TL. Sexual dimorphism develops during the breeding season. Males possess breeding tubercles uniformly distributed over their bodies, whereas female tubercles are limited to their heads, opercula and caudal regions (Muth et al. 1985). The genital orifice protrudes to a greater degree in ripe females than in ripe males (Neve 1976, Bestgen 1985). Both males and females typically exhibit orange-red coloration on the ventrolateral surface and on all fins except the dorsal (Vanicek and Kramer 1969, Neve 1976, Bestgen 1985, Muth et al. 1985); Bestgen (1985) noted that fish readily expressing gametes were the most tuberculate. Life-history Habitat. Roundtail chubs occur predominantly in pool-riffle habitats of CRB streams and rivers. Adults favor slow-moving, deep pools with access to feeding areas and cover such as large rocks, undercut banks, and woody debris (Barber and Hinckley 1966, Vanicek and Kramer 1969, Hinckley 1973, McAda et al. 1980, Lanigan and Berry 19$1, Valdez et al. 1982b, Bestgen 1985, Bestgen and Propst 1989, Rinne 1992, Barrett and Maughan 1995, Sigler and Sigler 1996, Brouder et al. 2000, Bryan and Robinson 2000, Beyers et al. 2001, Voeltz 2002). Roundtail chubs have also been found in reservoirs shortly after impoundment, but they do nat persist there (Olson i 967, Hinckley 1973, Wiley 1978, Schmidt et al. 1979, Schmidt and Brayton 19$1). Uncharacteristically, roundtail chubs are common in several lakes of the upper Crreen Final Re~rt September 2002 18