El Nino caused collapse of the sabalo fishery (Prochilodus lineatus, Pisces : Prochilodontidae) in a South American river

EI Nino is well known to affect marine fishery. The Southern Oscillation, h owever, may also have a strong effect on riverine fish production in floodp lains via its effect on river discharge. In years with high river discharge s larger parts of the floodplain are inundated, increasing the surface area of suitable nursery grounds for young fish stock. In this way high river d ischarges are thought to have a positive effect on fish production, while l ow discharges are thought to have a negative effect. The collapse of the sa balo fishery in the Pilcomayo River in Bolivia, for instance, can be attrib uted to the 1990-1995 El Nino event and subsequent overexploitation of the fish stocks.