Habitat Choice by Atlantic Salmon Parr in Relation to Turbulence at a Reach Scale

Abstract

Abstract.-The variables commonly used to describe the physical habitat of Atlantic salmon Salmo salar parr are average velocity, water depth, and substrate. A variety of micro-and mesohabitat models have been developed using these variables to assess habitat quality. However, Atlantic salmon parr live in highly turbulent streams and rivers in which intense fluctuations of water velocity occur. Laboratory experiments have shown that turbulence affects the behavior and energetics of fish. Nevertheless, habitat use in relation to the strong temporal variability of velocity in natural environments has rarely been studied. In this study, Atlantic salmon parr habitat was examined in relation to turbulence in the Patapédia River, Quebec. Rather than taking the usual approach of surveying a large population at one point in time, we used an intensive radiotelemetry tracking survey that focused on the habitat use of a few individual fish over an extended period. We analyzed habitat use in relation to several dynamic hydraulic variables. Our results revealed that under naturally turbulent conditions, the parr displayed high individual variability in their habitat use. Such heterogeneous use of habitat suggests that individuals are not constrained to a single habitat type. Furthermore, no differences were observed in habitat use among the four daily periods (dawn, day, dusk, and night) for individual parr.

The Ipos Framework: Linking Fish Swimming Performance in Altered Flows From Laboratory Experiments to Rivers

“…The morphological and hydrodynamic complexity of natural rivers provides challenges and opportunities for fish, including the avoidance and utilisation of turbulence associated with vortical flows. Swimming mechanics and fish physiology have mainly been observed for laboratory flume studies in which vortices are experimentally generated, for example, around a cylinder (for a review, see Liao, ), but field studies quantifying behavioural responses to turbulence are quickly emerging (Enders et al , ; Cotel et al , ; Enders et al , ).…”

Assessing hydrodynamic space use of brown trout, Salmo trutta, in a complex flow environment: a return to first principles.

“…Second, attempts to quantify habitat use by fish in the field typically produce mixed results (e.g. Heggenes et al, 1991;Facey and Grossman, 1992;Jowett and Richardson, 1995;Mäki-Petäys et al, 1997;Cotel et al, 2006;Enders et al, 2009). This is not surprising because space use is influenced by multiple confounding variables impossible to control in situ (e.g.…”

Characterization of hydraulic suitability of Chinese sturgeon (Acipenser sinensis) spawning habitat in the Yangtze River

“…The study shows that only the reach downstream of the Gezhouba Dam meets the spawning requirements for this species of fish. Kozarek et al (2007), Moir and Pasternack (2008) and Enders et al (2009) reported that many efforts have been made to protect and restore river habitats for brown trout (Salmo trutta), Chinook salmon (Salvelinus fontinalis), Atlantic salmon (Salmo salar) and other aquatic animals around the world. Conventional large-scale surveys and historical data on aquatic habitats often are used in these restoration and protection efforts.…”