Davies, Ronald W.Thompson, Gerald E.2005-07-192005-07-19197582480919http://hdl.handle.net/1880/15091Bibliography: p. 111-116.The ecology of mountain whitefish (Prosopium williamsoni) in the Sheep River, Alberta, was studied to determine its life history which was used as a basis for management recommendations. The study has elucidated the complex movements undertaken by the mountain whitefish, characterized by spring feeding, summer feeding, prespawning, spawning and post-spawning (overwintering) movements. A definite downstream prespawning and spawning movement has been shown with some fish moving in excess of 60 km in a two-week period . The spring feeding, summer feeding and post-spawning movements were identified but not quantified. There were indications that segments of the population of mountain whitefish in the Sheep River were non-migrant and do not undertake any movements in their adult lives. Some adults tagged in a particular location were repeatedly captured in exactly the same location over a period up to one year later. However, the majority of mountain whitefish appeared to be migratory and they moved downstream out of the upper Sheep River in September and October during prespawning, spawning and post-spawning movements. This resulted in an almost complete depopulation of the mountain whitefish population by adults in the upper Sheep River. They moved back into the upper Sheep River around the first of July. A movement to the upper Sheep River by non-adult mountain whitefish in October after the adults had moved downstream was indicated but not quantified. Recruitment to the population in the upper Sheep River took place at 2+ and 3+ years of age. It is possible that recruitment could take place at l+ or even O+ years of age, except a weir across the Sheep River at Turner Valley prevented these two year classes from moving upstream in September and October. A need to provide a fish passage facility at the weir was indicated. The diets of mountain whitefish consisted primarily of dipterans, ephemeropterans, trichopterans and terrestrial invertebrates. Growth is rapid except in the older age classes of 7+ and 8+. No mountain whitefish older than 8+ were collected in the Sheep River. The male mountain whitefish first matured at 3+ years of age while the females first matured at 4+ years of age. In the upper Sheep River, spawning took place in shallow, fast, midstream areas. The number of spawning fish on each spawning site was small (two to 20 fish per site). Spawning started in late September and continued to late October. The majority of spawning occurred between October 4 to October 10, 1973. The spawning substrate in the upper Sheep River was rock and rubble. Spawning took place in the lower Sheep River but the spawning sites ~re not identified. There were indications, however, that the number of spawning fish on probable spawning sites in the lower Shee~ River was large (approximately 500 fish).xv, 122 leaves : ill. ; 30 cm.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.QL 638 S2 T54 1974 MicroficheWhitefishesmaster thesis10.11575/PRISM/10948QL 638 S2 T54 1974 Microfiche