Protected areas and frugivorous fish in tropical rivers: Small-scale fisheries, conservation and ecosystem services

Abstract

1. Frugivorous fish provide often conflicting ecosystem services of seed dispersaland food provisioning in tropical rivers. Fishing may reduce the size andabundance of frugivorous fish, thus affecting their potential as seed dispersers,which could affect the conservation of these fish and of floodplain forests. 2. he goal of this study was to assess the influence of co-managed protected areasin the form of extractive reserves (RESEX) and small-scale fisheries on frugivorousfish in the Tapaj os and Negro rivers, in the Brazilian Amazon. The study examinedwhether: (i) frugivorous fish are important for fisheries and selectively caught; and(ii) frugivorous fish abundance, size and fisheries catch per unit of effort arehigher inside the RESEX than outside. 3. The analyses included fisheries-dependent data (3,753 fish landings) andindependent data (12,730 sampled fish) collected in 16 fishing communities(eight for each river). In both rivers, frugivorous fish are among the 10 speciescaught the most and frugivorous biomass was proportionately higher in landingsthan in samplings, indicating fisheries selectivity towards these fishes. 4. n both rivers, catches of frugivorous fish were higher outside the RESEX thaninside. Catch per unit effort and the proportion of frugivores in the catch werehigher outside the RESEX in the Tapaj os River but did not vary between sitesinside and outside the RESEX in the Negro River. Frugivorous fish were largerinside the RESEX in the Negro, but smaller inside the RESEX in the Tapajos. 5. he results indicated that the ecosystem services of seed dispersal and foodsource provided by frugivorous fish are not in conflict in the tropical riversstudied. Therefore, these clearwater and blackwater rivers in the BrazilianAmazon show a balance between fisheries and conservation of frugivorous fish,which play an essential role in the functioning of tropical floodplain forestecosystems.