Efeito da pesca comercial e esportiva sobre os “troféus” de tucunaré-açu (Cichla temensis, Humboldt, 1821) em um trecho do médio Rio Negro, Barcelos-Amazonas

Abstract

In the middle of the Negro River, commercial fishing and sporting activities have peacock bass as a common target. However, exploitation of the stock of this species occurs in a disorderly manner and information on how these activities occur in the region is scarce. Especially about sport fishing, which is one of the least studied fishing activities. Thus, this unprecedented study evaluates the stock of Cichla temensis in a stretch of the middle Rio Negro, where commercial and sport fishing activities occur with greater intensity. Data collection was carried out by applying semi-structured questionnaires to commercial and sport fishermen. The weight and total length of individuals caught by sport fishing were also measured. For the characterization of sport fishing, the average time of the season was recorded, which was six months, when tourism and fishing companies operate in five different modalities. The hotel-boat mode proved to be the most used by operators, as well as the oldest. For locomotion in fisheries, semi flattened canoes equipped with a 30HP engine are more used. 22 rivers were used for sport fishing, for preferential capture of the species Cichla temensis. The population analysis showed that the average total size of the speckled peacock bass tends to decrease with increasing fishing intensity. In the Generalized Linear Model performed for commercial fishing, it was possible to notice that all the predictive variables show a negative influence on the average total length, average weight and income of the fisheries, while in the GLM of sport fishing only the number of fishermen showed to exert such influence. The simulation model predicted that when fishing mortality is equal to natural mortality, there may be a reduction of 19.75 - 88.47% in the number of trophies entering the population. Even low exploitations would cause trophies to decline. The results presented here can be used for mixed management between commercial and sport fishing activities in the middle Negro River, since aspects that provide information on the scope of action, target species and stock status are known.