Habitat Selection and Intercohort Competition of Juvenile Sea-Trout Salmo trutta
- 1 January 1977
- Vol. 29 (1) , 112-117
- https://doi.org/10.2307/3543300
Abstract
By artificially changing the population density, the habitat preference of I+ sea-trout S. trutta L. with respect to different biotopes was studied by electro-fishing in a closed area of a small stream. The trout seemed to prefer pools or rocky substrates to shallow, smooth-bottom riffles. Marking experiments supported the hypothesis of "owner''s advantage" in the competition for space between resident and introduced fish, and revealed a marked stationarity in spite of possible experimental disturbances. There were significant differences between the mean lengths of I+ trout in the different biotopes, the deeper biotopes having the largest means. A few older trout showed a similar pattern. There were significant differences between the relative density of O+ trout in the different biotopes, the largest densities occuring in shallow, smooth-bottom riffles with low density of older trout. Stream tank experiments showed a tendency for competitive segregation between O+ and I+ trout, the latter being dominant and prefering pools to riffles. Field data of O+ and I+ density showed a biennial fluctuation with alternating peaks for O+ and I+ for a period of 5 consecutive years. Intercohort interaction, favored by drought, was a probable cause.This publication has 0 references indexed in Scilit: