Fishery regulamentation or ethnoknowledge? The dilemma of the management of the mapará fisheries on the lower Tocantins river in northern Brazil

The fishery of mapará (Hypophthalmus marginatus) is of great economic importance in the Amazon region. Despite this, it is observed that the current norms of management disagree with the ethnoknowledge of fishermen of the Tocantins river. Therefore, there are many seizures and fines in the Tocantins Low region. This work appeared as a demand of the fishermen of the region and had as purpose to test the pertinence of the fishing legislation on the capture of the species and to provide subsidies for the adaptation of the norms to the local reality. For this, a mapará fishery was taken on the Pindobal Grande river, in the municipality of Igarapé-Miri, in the state of Pará. A sample of the captured individuals was collected, and identification, sexing and biometry were done. Fishing was described, and the sex ratio tested with the Chi-Square test and the mean length differences between the sexes with the Student's t-test. The results were compared with current legislation and literature data. The captured mapará individuals were mostly above 30 cm, as determined by legislation. It is concluded that, despite using a network that is prohibited, the capture of the species in the region acts selectively, due to the ethno-cognition and the fisherman's action ("taleiro"). Therefore, it is necessary that the legislation be revised, seeking the reconciliation between the conservation of ecosystems, the traditional knowledge and the socioeconomic development of the region.