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Behavioural strategies for species co‐existence during environmental extremes: competition between trout and salmon parr during dewatering
Author(s) -
Stradmeyer L.,
Höjesjö J.,
Armstrong J.,
Griffiths S.
Publication year - 2003
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2003.216ak.x
Subject(s) - riffle , biology , competition (biology) , sympatry , ecology , rainbow trout , trout , habitat , fishery , niche , salmonidae , brown trout , range (aeronautics) , fish <actinopterygii> , materials science , composite material
Competition between species of animals can be predicted to be intense under extreme environmental conditions during which niche overlap increases. Fluvial aquatic systems fluctuate naturally across a broad range of time‐scales. Land management activities impose further extreme fluctuations, particularly when water is abstracted for irrigation during summer. This study focused on the interaction between Atlantic salmon and brown trout parr during acute dewatering events. Brown trout are known to compete strongly for pool habitat whereas salmon can coexist by using riffle areas during normal flows. It is not known, however, how competition between the species affects their behavioural responses to extreme low flows when riffle areas decrease. Replicated groups of salmon were held in allopatry and sympatry with trout in sections of a large indoor stream, each of which was landscaped into riffles and pools. Space use and behaviours of the fish were recorded by direct visual observations and a network of Passive Integrated Transponder detectors. Here we report the response of the fish to dewatering and consider the system as a model for natural and forced responses of communities to environmental extremes.