1986, ISBN: 9781234458812

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 80 pages. Original publisher: Washington, DC: National Ecology Center, Division of Wildlife and Contaminant Res… More...

RareBooksClub. Paperback. New. This item is printed on demand. Paperback. 80 pages. Original publisher: Washington, DC: National Ecology Center, Division of Wildlife and Contaminant Research, Research and Development, Fish and Wildlife Service, U. S. Dept. of the Interior, 1986 OCLC Number: (OCoLC)297224554 Subject: Brown trout. Excerpt: . . . incidence of straying has been confirmed ( Stuart 1953; Tilzey 1977 ). They generally move upstream in the fall to spawn or, in the case of lakes and reservoirs, into tributary streams. Females build nests or redds in the spawning gravel and demersal eggs are deposited and covered with gravel. After the spawning period, nests are left unguarded ( Greeley 1932; Breder and Rosen 1966 ). While brown trout usually spawn in running water, Borgeson ( 1966 ) reported successful spawni ng of brown trout over seepage areas of lakes. Adequate spawning habitat to support abundant trout populations appears to be 5 of the total trout habitat utilized in a river system, or an area equal to about 3 of the surface area of a lake. Brown trout are spawners wi th apparent 1at i tudi na 1 di fferences in fall time of onset. Spawning migrations appear to be triggered by decreasing day 1ength, increased 1ate flows, or drops in water temperature to 9 C fall ( Stuart 1953, 1957; Frost and Brown 1967; Ri eser and Wesche 1977 ), though these events are usually concurrent. In California, however, Staley ( 1966 ) reported that spawning often occurs when stream flows are low. Anadromy Anadromous brown trout breed in freshwater and, after a period of fresh-water residence, the young return to the sea to grow and mature. The young fish spend one to two growing seasons at sea and then return to their natal rivers in the fall to spawn. Like stee1head trout, many brown trout adults survive to spawn again. There are records of individuals spawning up to 12 times ( Mills 1971 ). Adult brown trout feed during the spawning run. In anadromous populations of brown trout, smo1tification results in changes in behavior and physio. . . This item ships from La Vergne,TN., RareBooksClub<