Influences of ENSO and PDO phenomena on the local climate variability can drive extreme temperature and depth conditions in a Pampean shallow lake affecting fish communities

CAROLINA, VERA; MIRANDA LEANDRO, A.; CAROLINA, VERA; MIRANDA LEANDRO, A.; MARIANO, ELISIO; MARIANO, ELISIO

ENVIRONMENTAL BIOLOGY OF FISHES

SPRINGER

Lugar: Berlin; Año: 2018 vol. 101 p. 653 - 666

0378-1909

The aim of this study was to characterizeoccurrence of extreme temperature and depth conditionsaffecting fish community in a shallow lake as result oflocal climate variability, in turn influenced by the ENSOand PDO phenomena. Extreme depth and water temperatureevents (modeled from local weather conditions)were characterized from 1966 to 2012 to estimatechanges in Chascomús lake fish communities. TheENSO and PDO influences on the occurrence probabilityof these ecosystem changes were investigated. Foursignificant changes in Chascomús Lake fish assemblagewere identified during period assessed, as response toextreme temperature and depth events. Extreme highdepth conditions would have changed fish communityduring 1987 and 2002, leading to a configuration characterizedby the absence of the most emblematic fishspecies in Chascomús Lake, the pejerrey (Odontesthesbonariensis). On the other hand, extreme low watertemperatures would have promoted a fish communitycharacterized by the dominance of this last species during1966?1986, 1997?2001 and 2008?2013 periods.Furthermore, extreme shortening in pejerrey spawningseason was significantly related with decrease of itsrelative abundance. The occurrence probability of theextreme physical conditions modifying ChascomúsLake fish communities was significantly explained byENSO (by depth influences) and by PDO (by watertemperature influences). Thus, this study showed strongcorrelations between the ENSO and PDOinfluences andthe occurrence probability of the extreme physical conditionschanging fish community in Chascomús Lake.