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Extrinsic and intrinsic factors influence daily activity of a Mediterranean cyprinid
Author(s) -
Martelo Joana,
Grossman Gary D.,
Filomena Magalhães M.
Publication year - 2013
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/eff.12027
Subject(s) - foraging , shoal , shoaling and schooling , ecology , mediterranean climate , benthic zone , biology , akaike information criterion , statistics , oceanography , mathematics , geology
Abstract Factors shaping individual behavior remain poorly understood for European cyprinids. We examined the effects of extrinsic (temperature and year) and intrinsic factors (body size and shoal size) on the daily activity of chub S qualius torgalensis , a critically endangered cyprinid found in the Torgal stream, Portugal. We quantified chub behaviors while snorkeling, using instantaneous sampling of focal individuals, in spring 2009 and 2010. We used Principal Component Analysis to describe individual behavior and assessed competing models relating individual behavior to explanatory variables using Akaike's Information Criterion. Year had a strong influence on chub behavior, with individuals spending more time drift foraging and orienting in 2009, whereas in 2010 they spent more time benthic foraging and cruising. Shoal size did not influence behaviors in 2009, but in 2010 individuals in small shoals foraged benthically and searched with greater frequency than those in large shoals. Individuals increased cruising and decreased searching as they grew in length, but the opposite trend was observed as temperature increased. Our results indicate that both extrinsic and intrinsic factors influence daily activity of chub, with individual behaviors varying between years, and depending upon shoal size, body size and temperature. This suggests that chub display high levels of individual behavioral flexibility, which may be important for fish inhabiting harsh and highly variable Mediterranean streams. Conservation efforts for this species will benefit by integrating behavioral information into management strategies.