Massive mortality of the giant freshwater mussel Anodontites trapesialis (Lamarck, 1819) (Bivalvia: Mycetopodidae) during a severe drought in a Neotropical reservoir

PASCHOAL LUCAS, R.; ANDRADE DOUGLAS; PIMPÃO DANIEL; TORRES SANTIAGO; DARRIGRAN GUSTAVO

ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS.

ACAD BRASILEIRA DE CIENCIAS

Lugar: Rio de Janeiro; Año: 2020 vol. 92 p. 1 - 13

0001-3765

In 2012, a severe drought struck the southeastern of Brazil compromising theParaná River Basin reservoirs. Here, we described how this climatic event promoteda massive mortality of the giant freshwater mussel Anodontites trapesialis in Furnasreservoir and reported the consequences of this phenomenon. In November 2012, threequarters of 100 m 2 were sampled in this reservoir, where 812 dead shells of A. trapesialiswere analyzed and measured (33 ˫ 133 mm). The species showed an aggregateddistribution with high density (: 1.0 - 5.5 ind/m 2). Despite the massive mortality detectedin f eld, it was possible to f nd living specimens in a small channel in the studied area,allowing the species to survive the water level f uctuations. Large adult individuals (100˫ 124 mm) were more affected by drought than juveniles, accounting for about 90% ofthe dead mussels analyzed. Two years after the massive mortality event, water levelwas not reestablished and a terrestrial succession (with elevations in the concentrationof organic matter and calcium in sediment) was observed in the studied area. Weverif ed that the damming associated with extreme climatic events affect negatively thepopulations of A. trapesialis and should be faced as a conservationist problem.