Application of ecohydrological criteria for the management of fisheries in the middle Paran River (Argentina) during extreme low water levels

Since 2019, there has been a long-duration low water event that has no previous records in the floodplain of the Parana River. This event highlights the lack of backgrounds and a lack of information on the socio-economic and ecohydrological impacts, as well as the difficulty of implementing relevant management measures to address this hydrological condition. This scenario has triggered several environmental and socio-economic conflicts associated with fishing activity. However, a conventional fisheries management approach with merely hydrological criteria is still carried out. This decoupling between the hydrological reality and the intensity of the fishing activity poses a threat to fish resources. The objective of this study was to discuss the application of ecohydrological criteria to advance the understanding of fish assemblage responses to the dynamics of hydrological processes in order to apply it to the management of the Parana River fisheries, particularly in scenarios of extraordinary low water levels. We conclude that available knowledge does not include a comprehension of the effects of prolonged low water level on commercial fish assemblage recruitment and structure during prolonged low water levels, and there is not enough knowledge to establish criteria to define the sustainable management of fishery resources.