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Ontogenetic Microhabitat Shifts in the Bullhead, Cottus gobio L.,in a Fast Flowing Stream
Author(s) -
Legalle Milène,
Mastrorillo Sylvain,
Santoul Frédéric,
Céréghino Régis
Publication year - 2005
Publication title -
international review of hydrobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 1434-2944
DOI - 10.1002/iroh.200410781
Subject(s) - cottus , abiotic component , habitat , ecology , streams , cottidae , environmental science , current (fluid) , ontogeny , range (aeronautics) , biology , hydrology (agriculture) , geology , fishery , sculpin , fish <actinopterygii> , oceanography , computer network , materials science , computer science , composite material , genetics , geotechnical engineering
We investigated differences in microhabitat preference curves for bullheads, Cottus gobio L., of different size‐classes during low flow periods, and evaluated the influence of such differences on habitat use through Weighted Usable Area (WUA) predictions in relation to river flow in a piedmont stream in Southwest France. Water depth, current velocity, and substratum composition were used to calculate proportional use values for each size‐class (SC), and to quantify size‐specific microhabitat preferences. Bullhead used non‐cohesive and coarse mineral particles (pebbles, cobbles, boulders), but there was a spatial segregation of individuals from different size classes (SC1–SC4). Smaller bullhead (SC1, total length <60 mm) took refuge under cobbles, significantly preferred shallower areas, and were less prone to select high current velocities than larger bullhead (SC 2 to 4, >60 mm), the latter occurring below (or under) the largest particles, where current velocity is weakened and sand accumulates. SC1 bullhead had a more restricted range for each habitat descriptors, and were thus likely to require a more specific habitat type than other bullhead. The maximum WUA values and the related preferred discharges (0.15–0.75 m 3 s –1 ) depended on the considered size‐class. Our results suggest that ontogenetic niche shifts may play a role in the structure and dynamics of populations, by adjusting species' requirements to the spatial and temporal dynamics of environmental conditions, including abiotic and biotic conditions. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)