Ecosystem indicators of a small-scale fisheries with limited data in madeira river (Brazil)

Abstract

This work presents an indicators-based analysis of a small-scale fishery operating in the middle Madeira River (Brazil), a tributary of Amazon River. We used landing species (kg) recorded daily by the Porto Velho fishermen’s colony from 1990 to 2009, with total length recorded in five selected years. The species were classified by trophic level, and the Fishing-in-Balance, L index, and size class distributions were calculated. In addition, differences in yearly total landings (kg) were correlated with the Madeira river water level (cm). The average annual catch was 566.5 tonnes (± 193.6), with significant variation between the years not correlated to the river water level. The ecosystem indicators showed a stable tendency, with oscillations in the latter years reflecting an increased catch of higher trophic level and larger species. Fisheries managers in data-limited regions should consider these indicators for fish stock analyses to be low cost, practical, and easy to calculate.