Conflicts between river dolphins (Cetacea: Odontoceti) and fisheries in the Central Amazon: a path toward tragedy?

Luiz Cláudio Pinto De Sá Alves,Artur Andriolo,Camilah Antunes Zappes

doi:10.1590/s1984-46702012000500005

Luiz Cláudio Pinto De Sá Alves, Artur Andriolo + Show 1 more

Open Access

https://doi.org/10.1590/s1984-46702012000500005

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Abstract

Dolphin interactions with fishermen have increased significantly and pose potential risks to the boto, Inia geoffrensis (Blainville, 1817), and the tucuxi, Sotalia fluviatilis (Gervais & Deville, 1853). The main objective of the present paper was to describe the existing conflicts between river dolphins and fishermen in the municipality of Manacapuru region. Sixteen fishermen were interviewed in Manacapuru, state of Amazonas, Brazil who described a situation of ongoing conflict that may be unsustainable. Two merchants from Manacapuru made unconfirmed reports on a boto carcass trade. Data collection for this study occurred between April 20th and April 25th, 2009, but the first author had been conducting research on river dolphins and fisheries in Manacapuru and nearby cities since the beginning of 2008, in order to gain the trust of the fishermen interviewed. The hunting and deliberate killing of the species is probably more threatening to botos than their incidental capture in fishing gears in the Manacapuru region. This practice may result from the fact that dolphins are prone to damaging fishing equipment, and stealing (and possibly damaging) fish from the nets. They are portrayed negatively in numerous myths and superstitions of traditional Amazonian folklore, making them extremely undesired or even hated, seen as pests, and used in the piracatinga, Calophysus macropterus (Lichtenstein, 1819) fishery as bait. For tucuxis, incidental capture still represents the major threat to their conservation in the region evaluated here.

Highlights

Conflicts between aquatic mammals and human activities have increased dramatically in recent years
The increased pressures from the fisheries in the Central Amazon in recent decades has greatly heightened the potential for river dolphin/fishery interactions; this in turn could adversely affect the status of the dolphins, through higher rates of incidental mortality in fishing gear, through direct competition for certain fish species (DA SILVA & BEST 1996), and more recently through the use of boto carcasses as bait during fishery activities (DA SILVA et al 2011)
In the Central Amazon, the accidental capture of I. geoffrensis for the carcass commercialization has become a social, cultural, and economical problem that could very likely reduce the populations of these animals

Summary

Introduction

Conflicts between aquatic mammals and human activities have increased dramatically in recent years. DA SILVA & BEST (1996) stated that all dolphin catches were probably incidental, and that only a very small number of carcasses were used for commercial purposes in the Central Amazon This situation has changed substantially, and the indiscriminate killing of dolphins in the Brazilian Amazon is frequent, adding up to incidental mortality and direct competition as an important factor that might adversely affect the situation of the dolphins. In 1997, conservation issues concerning cetaceans in Brazilian waters were improved, in particular through the institutionalization of the National Aquatic Mammal Research, Conservation, and Management Center (CMA/ IBAMA – Administrative Rule IBAMA 143-N/98) In this context, it is important to discuss the negative interactions that involve cetaceans and fishery activities in the country

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