Analysis of artisanal fisheries in two reservoirs of the upper Paraná River basin (Southeastern Brazil)

Abstract

We compared the artisanal fisheries, in terms of catch strategies, productivity, and gross per capita income, at two reservoirs: the Barra Bonita (an eutrophic reservoir with some introduced species), and the Jurumirim (an oligotrophic reservoir, with no introduced species). Published data and structured interviews with fishers were used to evaluate fishing activity, fish biomass, and the financial performance of the fisheries. In the Barra Bonita Reservoir we analysed data from 745 fishing trips, from which 86,691.9 kg of fish were landed, with a mean CPUE of 62.4 kg/fisher ), which constituted 24.5% of the biomass caught. Ordination analysis (PCA) indicated that there was a difference in composition between the fishing reservoirs and ANCOVA showed that there was a significant difference in fish production between the reservoirs. A Student's t-test showed that fishers in the Barra Bonita Reservoir had a significantly higher gross per capita income than those from the Jurumirim Reservoir. Although the Barra Bonita Reservoir has a higher fish production and the fishers earn a higher gross per capita income, we recommend the Jurumirim Reservoir as a model for artisanal fishery management because fishing activity in this reservoir is viable in the long term and such a model would promote conservation and sustainability. This contrasts with the Barra Bonita Reservoir, in which the fishery is not viable in the long term, due to environmental problems caused by artificial eutrophication and the introduction of alien species. It is also noted that in many countries, management of fisheries based on exotic species has not been viable in the long term.Nós comparamos a pesca artesanal, em termo de estratégia de captura, produtividade e renda per capita bruta em dois reservatórios: Barra Bonita (reservatório eutrófico e com espécies introduzidas) e Jurumirim (reservatório oligotrófico e sem espécies introduzidas). Dados publicados e entrevistas estruturadas mensais com os pescadores sobre a atividade de pesca, quilo pescado e rendimento financeiro, foram usados para as análises. ), que representou 24,5% da biomassa pescada. Uma análise de ordenação (PCA) indicou diferença na composição pesqueira entre os reservatórios e uma ANCOVA indicou diferença na produção pesqueira entre os reservatórios. Teste t de Student foi significativo e os pescadores do reservatório de Barra Bonita tiveram maior renda per capita bruta. Embora o reservatório de Barra Bonita tenha tido maior produção pesqueira e os pescadores maior renda, recomendamos o reservatório de Jurumirim como modelo para gestão de pesca artesanal nos reservatório, pois a atividade mostrou ser viável em longo prazo bem como ecologicamente correto. Isto contrasta como o reservatório de Barra Bonita, em que a pesca não é viável em longo prazo, devido a problemas ambientais provocados pela eutrofização artificial e pela introdução de espécie. Observou-se que em muitos países, o manejo da pesca com espécies exóticas, não tem sido viável em longo prazo.

Fish diversity in the cascade of reservoirs along the Paranapanema River, southeast Brazil

“…Reservoirs located downstream were more invaded (i.e., species richness and abundance), supporting previous studies that reported high invasion rates (Garcia et al, 2018) or strong impacts (Orsi, Britton, 2014;. Jurumirim reservoir was the less invaded and, consequently, has been considered a model for sustainable artisanal fisheries (Novaes, Carvalho, 2013), because fishing activities are based on native species, with higher prices, and may be sustained in the long term. The current scenario in the cascade of impoundments, therefore, demands immediate management actions to control populations (e.g., selective fishing) and to prevent new introductions (e.g., education, inspection), mainly because impoundments are vulnerable to new introductions (e.g., Espinola et al, 2010;Franco et al, 2018).…”

Fish fauna from the Paranapanema River basin, Brazil

“…Despite the significant richness of fish species known, the region of the Paranapanema River has the highest population density in Brazil (ANA 2016) as a result of electricity production, agribusiness, industry, and water supply (Novaes & Carvalho 2013) occurring in the area. Additionally, it is also used as a source of livelihood for riverside communities (Agostinho et al 2007b(Agostinho et al , 2016.…”

O que dizem as pesquisas acadêmicas sobre os impactos das hidrelétricas na pesca artesanal?

“…Outro tema importante abordado em parte dos estudos foi sobre introdução / manutenção de espécies exóticas nos reservatórios e seus efeitos nas espécies nativas (AGOSTINHO et al, 2004;CARVALHO, 2011A;CARVALHO, 2011B;CARVALHO, 2013;SCHORK et al, 2013;DAVID et al, 2016;SANTA-FÉ et al, 2016 , 1998;BAIRD et al, 2004;TOS et al, 2009;DORIA et al, 2012;HEGG et al, 2015;DUPONCHELLE et al, 2016;SIDDONS et al, 2017). No caso de Tucuruí, os grandes bagres migradores podem ter sido os mais prejudicados com a interrupção do fluxo migratório promovido pela barragem (GARAVELLO et al, 2010).…”