Effects of riffle length on the short-term movement of fishes among stream pools

Ayllón D, Almodóvar A, Nicola GG, Elvira B. Ontogenetic and spatial variations in brown trout habitat selection. Ecology of Freshwater Fish 2010: 19: 420–432. © 2010 John Wiley & Sons A/S Abstract – Habitat quality and quantity determine many biological processes and traits that directly affect the population dynamics of stream fishes. Understanding how habitat selection is adjusted to different ecological conditions is essential to improve predictive modelling of population dynamics. We describe brown trout Salmo trutta summer habitat selection patterns through univariate and multivariate habitat selection functions across defined river reach typologies. We sampled 44 sites and performed a principal component analysis that defined eight reach types differing in both local site and catchment‐scale physical features. We observed ontogenetic changes in habitat selection, as trout preferred deeper and slower flowing water as they increased in size. Likewise, selectivity for different types of structural habitat elements changed through ontogeny. Both patterns were consistent across reach types. Moreover, we detected spatial variations in habitat selection patterns within age‐classes among different reach types. Our results indicate that brown trout is a habitat generalist and suggest that spatial variations in habitat selection patterns are driven by physical and environmental factors operating at multiple spatial scales.

Section: Discussionsupporting

confidence: 88%

Ontogenetic and spatial variations in brown trout habitat selection

Ayllón

Almodóvar

Nicola

et al. 2010

“…3). Riffle length may also have played a role in limiting the short-term movement of brown trout by spatially isolating pools during periods of low (base) flow (Lonzarich et al 2000). The existence of extensive riffle areas within Section 3 may, therefore, have reinforced the temperature-driven tendency for reduced movement with the addition of a physical barrier.…”

Section: Discussionmentioning

confidence: 99%

Seasonal movement patterns of Credit River brown trout (Salmo trutta)

Zimmer¹,

Schreer

Power

2010

Zimmer M, Schreer JF, Power M. Seasonal movement patterns of Credit River brown trout (Salmo trutta). Ecology of Freshwater Fish 2010: 19: 290–299. © 2010 John Wiley & Sons A/S Abstract – Movement habits in riverine populations of brown trout vary among watersheds. Thus it is important to identify factors influencing differences in individual behaviour so as to improve the information resource base available for the design of river‐specific management strategies. Such information is particularly needed in the rapidly urbanising watersheds of eastern North America where relatively little is known about anthropogenic influences on brown trout populations. In this study, we examined the influence of water temperature on brown trout behaviour in the Credit River in south‐central Ontario, Canada with respect to seasonal movement patterns. Observed patterns of movement were also correlated with variations in river discharge and habitat quality. Forty‐three radio‐tagged, adult brown trout were tracked in a confined 39.8 km portion of the Credit River from 15 May 2002 to 28 July 2003. Fish were captured in three sections of the river that differed in distance downstream and habitat quality. Fish size had little impact on movement patterns. However, there was considerable variation in seasonal movement with upstream movements to summer positions, maintenance of summer positions, downstream and often extensive movements in fall. Also observed was maintenance of winter positions and repeated upstream movements in late spring‐early summer to previously used summer positions. The elaborate movement behaviour in the Credit River population was attributed to seasonal changes in thermal habitat quality. Fish tagged in less suitable thermal habitats moved significantly more than fish from more suitable thermal habitats.

“…Only 12% of 25 fishes moved out of the pools, where they had been marked during May through October. However, the study stream was small, with pools connected by shallow riffles that may have deterred movements by creek chubs (Lonzarich et al. 2000).…”

Section: Discussionmentioning

confidence: 99%

“…1998; Labbe & Fausch 2000). Less is known about the reasons for short‐distance movements, although researchers have suggested such movements allow fish to respond to changing resource conditions or predation risk (Fraser & Sise 1980; Gowan & Fausch 1996; Smithson & Johnston 1999; Lonzarich et al. 2000).…”

Section: Introductionmentioning

confidence: 99%

Movements of creek chubs, Semotilus atromaculatus, among habitat patches in a plains stream

Belica

Rahel

2007

– We studied summer movement patterns of creek chubs, Semotilus atromaculatus, in a low‐gradient, sand‐bottomed stream on the western plains of the United States. Creek chubs were highly associated with patches of cover consisting of wood or macrophytes. Movements among 37 patches in a 1.1‐km segment were assessed in a mark‐recapture study. Over 2‐week intervals, 44% of recaptured fish changed patches. Net distances moved ranged from 4 to 606 m, median distance moved was 49 m. Of fish recaptured repeatedly during the four sampling periods, most (65%) changed patches at least once, but few were consistently mobile. Inter‐patch distance was an important variable with a negative effect on creek chub movements. Inter‐patch cover was less important, but had a positive effect on movements. Frequent, short‐distance movements among habitat patches in summer are a component of the ecology of creek chubs and the spatial arrangement of patches, and intervening stream conditions appear to mediate those movements.