A caça comercial de jacarés no baixo rio Purus e suas implicações no manejo sustentável na Reserva Piagaçu-Purus, Amazônia Central

Abstract

This study valuated the caimans hunting with hook practiced in the Low Purus river at the Sustainable Development Reserve (RDS) Piagaçu-Purus, Central Amazon. This activity is realized by the riveriner aim the caiman meat production in salt-dry to supply the interstates trade. The knowledge scenery about the hunting of caiman with hook was put in public since 2003, however, not much is know about this catch effects on the caiman hunting productivity and its catch length. Aim to valuate the effect of this catch, were accompanied 31 caiman hunting with hook in the period of February to October 2008. Multiple Linear Regressions and Simple Linear Regression Analyzes were applied to model the caiman catch production and size. The mass of meat produced by the hunting were modeling in function of the river water level, community distance and hunting effort using hook. Were caught 124 caimans, where: 53 with suspense hook and 71 with the hook armed under land. The modeling of the size of hook and to water deep explained 48% of caiman length variance, while the modeling that used the height of hook parameter above the water surface and water deep explain 38% of this variance. The Simple Linear Regression was utilized to modeling the caiman length caught in function of distance hook traped under land from the interface water-land, showing a variance of 60% for the sample size. The hunting effect presented in this study indicates the intensive hunting pressure on the caiman population, confirmed through produced caiman meat decreasing near to hunters communities. Confirmed through Multiple Linear Regression values expressed for 70% of variance for this production. Was observed too that the caiman hunting are proportionally inverse to the river water level. The Caiman crocodilus caught length present higher abundance of individual above 70cm of snout-vent length. This indicate that the hunting method guard the replacement individuals to maintain the caiman population. While the Melanosuchus niger specie had the higher abundance of caught individual sub adult, noting the reduction of big adults. The absence of this caiman length class sustain the hypothesis that the individual lenght structure of M. niger population are probably affected by the intense hunting pressure. The results presented can be utilized to subsides the public policy for assert the sustainable management of caiman in the Amazon States, Brazil.