Da base para o topo : teias tróficas e cenários de esforço pesqueiro para as baías de Chacororé e Sinhá-Mariana no Pantanal mato-grossense

Abstract

Fishing is an essential activity in Neotropical regions. In the Pantanal, this activity holds economic and social importance. The implementation of measures to restrict fishing has been taking place for decades in the Pantanal. In 2024, Law No. 12.434/2024 was approved and implemented, prohibiting fishing of 12 fish species in the Pantanal region of Mato Grosso, under the argument of overfishing. However, the lack of data demonstrating the presence of the protected species may compromise the effectiveness of this law. The objective of this study was to create trophic web models and simulate different fishing effort scenarios for commercially targeted fish species in the Chacororé and Sinhá-Mariana bays, located in the Pantanal of Mato Grosso. The fishing effort simulations were carried out over a 30-year prediction period, considering five years of fishing prohibition followed by 25 years of fishing being allowed. The models were developed using the software Ecopath With Ecosim, a tool used for fisheries management.The evaluated ecosystem attributes indicate that the systems operate in a bottom-up manner and are not very resilient, despite being productive. The models identified Hemisorubim platyrhynchos, Salminus brasiliensis, Pseudoplatystoma corruscans, Hoplias malabaricus, Serrasalmus spp., Plagioscion ternetzi, and Acestrorhynchus pantaneiro as key species in the bays. The fishing effort simulations showed that the maximum biomass increase under the fishing ban scenario was 1%, while the maximum biomass reduction under fishing pressure was 0.6%. In other words, the biomass variation between the two scenarios is minimal. These results suggest that fishing effort would need to be considerably higher than current levels to result in overfishing of the commercial target species considered in the simulations. Therefore, the law may be of limited effectiveness for the systems studied.