Challenging convention: the winter ecology of brown trout (Salmo trutta ) in a productive and stable environment

Kemp, Paul S.; Vowles, Andrew S.; Sotherton, Nick; Roberts, Dylan; Acreman, Michael C.; Karageorgopoulos, Perikles. 2017 Challenging convention: the winter ecology of brown trout (Salmo trutta ) in a productive and stable environment. Freshwater Biology, 62 (1). 146-160. https://doi.org/10.1111/fwb.12858

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Official URL: http://dx.doi.org/10.1111/fwb.12858

Abstract/Summary

1. Understanding of the winter ecology of stream salmonids is biased by research conducted in northern temperate and boreal regions dominated by hard rock geology. Such systems are driven by highly dynamic surface-flow regimes and tend to be physically diverse, nutrient poor and influenced by ice. This study investigated how the behaviour of brown trout, Salmo trutta, inhabiting a stable groundwater-fed, productive and comparatively warm southern English chalk stream differs from that described for other systems, and how this is translated to performance, measured as growth. 2. Physical characteristics were mapped, and high-resolution temperature data collected using a spatial array of data loggers installed throughout the study reach during the winter. A combination of passive integrated transponder and radio telemetry was used to monitor distribution, density, and movement of trout. Micro-archival data storage tags inserted in some individuals provided information on temperature regimes experienced. Growth performance was calculated for recaptured fish. 3. Trout density was positively related to depth and there was no evidence that temperature influenced microhabitat selection. Three patterns of movement were observed. Over three-quarters of tracked fish exhibited high site fidelity and tended to remain in a single focal position throughout the study. Fourteen per cent of trout exploited more than one distinct location, while the remainder were detected at multiple locations and showed no preference for any one. 4. Trout exhibited regular daily activity patterns and highly periodic local movements at dusk and dawn and tended to experience positive growth performance during periods that included winter. 5. This study challenges the conventional view of salmonid winter ecology, which is biased towards populations that inhabit hard rock surface-flow dominated rivers that experience the influence of ice. Despite inhabiting a distinctly different winter habitat template than more commonly studied populations, trout occupying a hydrologically stable and productive chalk stream exhibited behaviours similar to those described for elsewhere, yet performed considerably better.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1111/fwb.12858
UKCEH and CEH Sections/Science Areas:	Acreman
ISSN:	0046-5070
Additional Keywords:	brown trout, chalk stream, habitat models, habitat template concept, salmonid, site fidelity
NORA Subject Terms:	Ecology and Environment Zoology
Date made live:	04 Apr 2017 14:59 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/516788

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1111/fwb.12858

UKCEH and CEH Sections/Science Areas:

Acreman

ISSN:

0046-5070

Additional Keywords:

brown trout, chalk stream, habitat models, habitat template concept, salmonid, site fidelity

NORA Subject Terms:

Ecology and Environment
Zoology