. The Canadian field-naturalist. 160 The Canadian Field-Naturalist Vol. 102. Figure 3. Collection records of H. x-punctata in Ontario. is minimal and instream vegetation is restricted to encrusting and filamentous algae. Water tempera- tures ranged from 18 to 25°C in July (Holm and Grossman 1986), 21 to24°Cin August (Parker and McKee 1987) and 12 to 15°C in October (Holm and Grossman 1986). Elsewhere in North America, Gravel Ghub have been reported as inhabiting clear to moderately turbid streams with permanent flow and well- defined sand, gravel or rocky riffles where the current keeps the ri
. The Canadian field-naturalist. 160 The Canadian Field-Naturalist Vol. 102. Figure 3. Collection records of H. x-punctata in Ontario. is minimal and instream vegetation is restricted to encrusting and filamentous algae. Water tempera- tures ranged from 18 to 25°C in July (Holm and Grossman 1986), 21 to24°Cin August (Parker and McKee 1987) and 12 to 15°C in October (Holm and Grossman 1986). Elsewhere in North America, Gravel Ghub have been reported as inhabiting clear to moderately turbid streams with permanent flow and well- defined sand, gravel or rocky riffles where the current keeps the river bottom free of unconsoli- dated silts and clays (Pflieger 1975; Trautman 1981). Trautman (1981) reported that the species avoided areas with macrophytes, larger species of algae and aquatic mosses. Presumably these areas would show silt accumulation. Moore and Paden (1950) described the preferred micro-habitat of the Gravel Ghub as small cavities beneath rocks in riffle areas where the current is reduced. General Biology Nothing is known of the biology of Gravel Ghub in Ganada and little has been reported on this species for American populations {see Becker 1983). Specimens from the North Thames River were 52-57 mm long and, based on data for specimens from Ohio (Trautman 1981), it is probable that the Ontario specimens were adults. Spawning is reported to occur in early spring on swift gravelly riffles in Kansas (Gross 1967). The food probably consists of epibenthic insects (Parker and McKee 1980). Davis and Miller (1967) found that the taste buds on the Gravel Ghub's barbels were extremely large suggesting that this species feeds by probing under rocks and into crevices with its sensitive snout. Limiting Factors The habitat requirements of the species are narrow and populations are confined to areas where there is sufficient current to keep the bottom free of silt {see Becker 1983). The species is susceptible to turbidity and siltation (Becker 1983). Increased siltatio
Size: 1934px × 1293px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorottawafieldnaturalistsclub, bookcentury1900, bookcolle
