The populations of fish in tributaries of the River Eden on the Moor House National Nature Reserve, northern England
✍ Scribed by D.T. Crisp; P.R. Cubby
- Publisher
- Springer
- Year
- 1978
- Tongue
- English
- Weight
- 553 KB
- Volume
- 57
- Category
- Article
- ISSN
- 1573-5141
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✦ Synopsis
The population dynamics of trout (Salmo trutta L .) were studied in two high-altitude streams flowing westwards into the River Eden in northern England . The results from one (Knock Ore Gill), which is accessible to spawners from downstream, were compared with published data from an isolated population in a nearby stream which flows eastward into the River Tees . The Knock Ore Gill trout had a population density of 0.4-0.9 fish m -', a biomass of 12 .4 g M-2 , annual production of 12-14 g m_' year' and an instantaneous mortality rate of 0 .97 year-' . Comparable values from the Tees tributary were 0 .2, 3 .3, 2 .3 and o .66 respectively . The Knock Ore Gill population also contrasted with that of the Tees tributary in having reliable recruitment from year to year . These differences were related to differences in the chemistry and spate characteristics of the two streams and to the fact that immigrants from downstream were responsible for over 30% of the annual oviposition in Knock Ore Gill .