River regulation and fish communities in the Murray-Darling river system, Australia

摘要: Fish communities from four catchments in the Murray—Darling river system were analysed relation to climate, hydrology and regulation. Using annual proportional flow deviation as a measure of regulation, Paroo River catchment was assessed unregulated, Darling mildly regulated Murrumbidgee Murray highly regulated. A total 11010 fish, representing nine native three alien species, caught during high low seasons catchments. Native such golden perch Macquaria ambigua (Percichthyidae), bony herring Nematalosa erebi (Clupeidae) spangled Leiopotherapon unicolor (Teraponidae), dominated fish catchments, but mostly carp, Cyprinus carpio (Cyprinidae), also abundant. Both species more abundant these after flooding, there little change composition between at level. Carp There significant trend for reduced diversity increasingly regulation may alter relative abundance by desynchronizing environmental cycles reproductive species. Ordination abundances showed discrete that reflect geographical separation Differences are related opportunities dispersal, tolerances dominant modifying effects lakes exhibited less seasonal variation than riverine within same catchment, indicating greater stability compared with unregulated reaches. Management resources needs include catchment-specific strategies current State basin-wide management programmes.