Use of three types of stream-margin habitat by age-0 brown trout late in the growing season

Abstract

The use of stream-margin habitat by age-0 salmonids has been studied, but differences in use among various types of habitat along stream margins has not been addressed . We described the nighttime use of habitat features by age-0 brown trout (Salmo trutta) among three types of stream-margin habitat late in the growing season (AugustSeptember) and assessed the extent to which use of habitat features within each type differed over the sampling period . Differences in water depths, water velocities, distances from shore, and substrate at the locations of fish along the margins of pools, the margins of riffles, and in backwaters were studied . Variation in habitat use also was observed during the study period as fish increased in length . Our observations are important considerations when developing habitat suitability criteria for assessment of instream-flow needs of age-0 brown trout .

Influence of water quality, habitat and species richness on brown trout populations

“…For 0+ trout this may relate to the greater proportion of stream bank to interior habitat in narrow streams than in broader streams. Marginal habitats with shallow and slow-flowing areas are suitable habitats for trout fry (Heggenes, 1988;Moore & Gregory, 1988;LaVoie & Hubert, 1996). Stream margins with complex habitat structure may permit visual isolation among territorial individuals and thereby allow more individuals to coexist (Chapman, 1966;LeCren, 1973).…”

“…Further, alteration of physical habitat through canalization changes depth and substratum composition in stream beds, which in turn may impact spawning and rearing habitat for brown trout negatively. This is because brown trout need gravel streambeds for successful spawning, and intact marginal habitats with shallow, slow-flowing areas as nursery grounds for fry (LaVoie & Hubert, 1996;Rubin & Glimsäter, 1996).…”

Habitat De La Truite Commune (Salmo Trutta L.) Pendant La Période Juvénile en Ruisseau : Préférences, Mouvements, Variations Journalières Et Saisonnières.

“…Une fois la taille de 50 mm (LF) atteinte, ils semblent abandonner progressivement les habitats de bordure la nuit (LAVOIE et HUBERT, 1996), et la hauteur d'eau devient un paramètre essentiel du placement des juvéniles. Cet aspect a été étudié dans la suite du travail par le biais d'inventaires en milieu naturel.…”

“…(Figure 6, B). C'est dans les faciès courants de type radier que l'on trouve les plus fortes densités d'alevins, mais les berges des faciès plus profonds peuvent également être utilisées (LAVOIE et HUBERT, 1996).…”