Ref ID : 5887
E. Martinez-Ansemil and N. Prat; Oligochaeta from profundal zones of Spanish reservoirs. Hydrobiologia 115:223-230, 1984
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The profundal benthic fauna of 63 Spanish reservoirs was studied during 1972-75. Samples were taken in the deepest part of each reservoir with a modified Van Veen grab. The fauna was dominated by tubificid worms and chironomids. Sixteen species of Oliochaeta were found, two of them new for the Spanish fauna (Potamothrix heuscheri and Haber pyrenaicus). This was the first time H. pyrenaicus was found since the species was described in 1974 from the Pyrenees. Four species were frequent in the reservoirs (Limnodrilus hoffmeisteri, Tubifex tubifex, L. claparedeianus and Dero digitata) but only the first two were abundant as mature individuals. Another interesting fact is the high abundance of immature animals in all samples, accounting for more than 80% of the total individuals examined. The geographical distribution of all species in Spain and their relationship with the typology of Spanish reservoirs are discussed. There seems to be a correlation between the trophic status of the reservoirs and the relative proportion of L. hoffmeisteri as compared to T. tubifex, the number of individuals of the first species increasing with water eutrophication.