Perceptions of environmental changes and Lethargic crab disease among crab harvesters in a Brazilian coastal community

Angélica Ms Firmo,Rômulo Rn Alves,Walter Lo Có,Raynner Rd Barboza,Mônica Mp Tognella

doi:10.1186/1746-4269-7-34

Abstract

BackgroundLethargic Crab Disease (LCD) has caused significant mortalities in the population of Ucides cordatus crabs in the Mucuri estuary in Bahia State, Brazil, and has brought social and economic problems to many crab-harvesting communities that depend on this natural resource. The present work examined the perceptions of members of a Brazilian crab harvesting community concerning environmental changes and the Lethargic Crab Disease.MethodsField work was undertaken during the period between January and April/2009, with weekly or biweekly field excursions during which open and semi-structured interviews were held with local residents in the municipality of Mucuri, Bahia State, Brazil. A total of 23 individuals were interviewed, all of whom had at least 20 years of crab-collecting experience in the study region. Key-informants (more experienced crab harvesters) were selected among the interviewees using the "native specialist" criterion.ResultsAccording to the collectors, LCD reached the Mucuri mangroves between 2004 and 2005, decimating almost all crab population in the area, and in 2007, 2008 and 2009 high mortalities of U. cordatus were again observed as a result of recurrences of this disease in the region. In addition to LCD, crabs were also suffering great stock reductions due to habitat degradation caused by deforestation, landfills, sewage effluents, domestic and industrial wastes and the introduction of exotic fish in the Mucuri River estuary. The harvesting community was found to have significant ecological knowledge about the functioning of mangrove swamp ecology, the biology of crabs, and the mass mortality that directly affected the economy of this community, and this information was largely in accordance with scientific knowledge.ConclusionsThe study of traditional knowledge makes it possible to better understand human interactions with the environment and aids in the elaboration of appropriate strategies for natural resource conservation.

Highlights

Lethargic Crab Disease (LCD) has caused significant mortalities in the population of Ucides cordatus crabs in the Mucuri estuary in Bahia State, Brazil, and has brought social and economic problems to many crabharvesting communities that depend on this natural resource
Perceptions of environmental changes When asked about their relationships with the mangrove forests, the interviewees reported being directly linked with those environments and they considered the estuary to be one of the most important features in their lives - especially since their economic survival was almost completely dependent on crab harvesting
When asked about how to best protect the mangrove forests and the mangrove land crabs, the interviewees gave different responses. Some replied that they would like to act as monitors to prohibit capture during the reproductive period, while others stated that people should stop destroying the mangrove forests and restore the environment, and avoid polluting the river estuary

Summary

Introduction

Lethargic Crab Disease (LCD) has caused significant mortalities in the population of Ucides cordatus crabs in the Mucuri estuary in Bahia State, Brazil, and has brought social and economic problems to many crabharvesting communities that depend on this natural resource. The present work examined the perceptions of members of a Brazilian crab harvesting community concerning environmental changes and the Lethargic Crab Disease. Brachyura crabs are a major economic resource for the coastal dwellers of northeastern. High predation pressure is exerted on U. cordatus by humans, who harvest this species for direct consumption [10] and principally for commercialization. The harvesting of U. cordatus has significant socioeconomic importance in northeastern Brazil and involves many local residents who benefit both directly and indirectly from commerce involving this species [7,11]

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