Effect of hydropeaking on migrations and home range of adult Barbel (Barbus barbus} in the river Meuse

摘要

The non-navigable part of the River Meuse, forming the border between Belgium and the Netherlands, is 60 to 100 metres wide and has an average slope of 0.45 mkirr~(-1). The river has been modified by gravel extraction, bank stabilization, summer dykesand flow modifications. To document fish use of this system, fourteen adult and female (Fork Length: 47.5-57 cm) barbel (Barbus barbus) were radio tagged (40 MHz): 5 in May 2001, 3 in October 2001 and 6 in April 2002. From May 2001 till September 2002 fishes were localized weekly throughout the year and daily in April and May to identify spawning grounds and investigate seasonal migrations and home range. In winter, when flows ranged from 250 to 2 800 m~2s~(-1), barbel were found in the main river bedat all times. No downstream migrations to sheltered parts of the river were observed. In spring, both upstream (0.2 km) and downstream (up to 2.6 km) migrations to spawning grounds were observed. Individual barbel, in the mouth of a tributary, showed different migrations towards spawning areas and holding locations under low flow conditions. Migrations in summer and autumn were directed by changes in flow and habitat suitability. The home ranges of the barbel ranged from 1.05 to 27.3 km and differed significantly in size for different parts of the river. Resident habitat suitability is determined by discharge, water depth, water current and bottom structure. Total home ranges of barbel, occupying a highly structured part in the river with continuous availability of suitable habitat for spawning, resting and foraging were significantly smaller (1490 m) than those for barbel initially caught in areas with less habitat diversity (12.5 km).