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The Serra Spanish mackerel fishery , no sul do Brasil: o aumento nos desembarques de um recurso de alto nivel trofico
In fisheries, the phenomenon known as fishing down food webs is supposed to be a consequence of overfishing, which would be reflected in a reduction in the trophic level of landings. In such scenarios, the resilience of carnivorous, top predator species is particularly affected, making these resourc...
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Published in: | Brazilian journal of biology 2023-01, Vol.83 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | In fisheries, the phenomenon known as fishing down food webs is supposed to be a consequence of overfishing, which would be reflected in a reduction in the trophic level of landings. In such scenarios, the resilience of carnivorous, top predator species is particularly affected, making these resources the first to be depleted. The Serra Spanish mackerel, Scomberomorus brasiliensis, exemplifies a predator resource historically targeted by artisanal fisheries on the Brazilian coast. The present work analyzes landings in three periods within a 50-year timescale on the Parana coast, Southern Brazil, aiming to evaluate whether historical production has supposedly declined. Simultaneously, the diet was analyzed to confirm carnivorous habits and evaluate the trophic level in this region. Surprisingly, the results show that from the 1970's to 2019 Serra Spanish mackerel production grew relatively to other resources, as well as in individual values. The trophic level was calculated as 4.238, similar to other Scomberomorus species, consisting of a case where landings increase over time, despite the high trophic level and large body size of the resource. The results agree with a recent global assessment that has demystified a necessary correlation between high trophic level and overexploitation, but possible factors acting on the present findings are discussed. Keywords: fishing, overfishing, diet, Scombridae, Brazil. Na pesca, o fenomeno fishing down food webs, ou 'pescando teias troficas abaixo', expressa a reducao do nivel trofico na composicao das capturas, e tem origem tradicionalmente atribuida a sobrepesca. Sob intenso extrativismo, a resiliencia das especies carnivoras, predadoras de topo, e particularmente afetada, sendo seus estoques os primeiros a entrarem em deplecao. A cavala, ou serra, ou sororoca, Scomberomorus brasiliensis, e exemplo de recurso predador historicamente alvo da pesca artesanal, de pequena escala, na costa brasileira. O presente trabalho analisa os valores de desembarque do recurso em tres periodos ao longo de 50 anos na costa paranaense, sul do Brasil, com objetivo de avaliar se sua producao tem efetivamente diminuido. Ainda, estuda-se a dieta da especie na regiao, para confirmar seus habitos carnivoros e avaliar o nivel trofico na regiao. Os resultados mostram que, surpreendentemente, dos anos 1970 para 2019 a producao de S. brasiliensis tem aumentado em valores absolutos, bem como relativamente a de outros recursos, em que pese o nive |
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ISSN: | 1519-6984 |
DOI: | 10.1590/1519-6984.246180 |