The shrimp trawl fisheries are highly efficient in capturing target species but is an unselective gear that commonly catches untargeted organisms, which are usually discarded due to their small size or no commercial value. To understand and, eventually, mitigate the impacts of trawling on bycatch species, the whole capture should be addressed. The present study has the objective of determining the seasonal importance of the fish bycatch within shrimp trawling fishery in south Pernambuco, Sirinhaém. It also quantifies the importance of each fish caught within this fishery. Samples were collected monthly, between August 2011 and July 2012. Fish bycatch was described as % in number (%N) and weight (%W), while the seasonal abundance of the shrimp and fish bycatch was assessed based on the monthly catch rate given as the Capture Per Unit of Area (CPUA) in weight (CPUAb) and in number of individuals (CPUAn). Considering the fish bycatch, a total of 608 kg of organisms were sampled: 9,723 fish specimens from 17 families, 38 genera and 51 species. The largest CPUAb value of bycatch was observed in the months of June (488 kg.km-2), February (285 kg.km-2) and April (276 kg.km-2). The proportion target species: bycatch in weight was of 1:0.39. A clear annual cyclic pattern of the species composition of the bycatch based both CPUAn and CPUEb could be observed, following the rainfall patterns, possibly related to a higher productivity associated to river runoffs. Impacts on bycatch have been extensively reported in Brazil and around the world, with most of this bycatch being a relevant additional food source for the local community. However, basic information on bycatch from small-scale fisheries is still missing in many areas, making it difficult to identify and evaluate the management recommendations needed to sustain the resources and ecosystems.
ABSTRACT. The Brazilian prawn fishery, as other bottom trawling fisheries, is considered quite efficient in catching the target species but with low selectivity and high rates of bycatch. The family Sciaenidae prevails among fish species caught. The study was conducted in the Pernambuco State (Barra de Sirihaém), northeastern Brazil. From August 2011 to July 2012, 3,278 sciaenid specimens were caught, distributed into 16 species, 34.2% males and 41.5% females. Larimus breviceps, Isopisthus parvipinnis, Paralonchurus brasiliensis and Stellifer microps were the most abundant species. The area was considered a recruitment and reproduction area with the highest reproductive activity between December 2011 and July 2012. The constant frequency of mature I. parvipinnis and S. microps in catches throughout the year suggests that these species are multiple spawners and use the area during their reproductive period. Since most individuals caught as bycatch have not reached sexual maturity, evidencing the need for a better monitoring of the area and the Sciaenidae caught as bycatch, once this incidental caught can cause fluctuations in the recruitment, increasing the proportion of immature individuals in the population and negatively affecting the reproductive success of the species.Keywords: Demersal, trawling, sexual maturity, coastal zone.Aspectos da biologia reprodutiva e caracterização de cianídeos capturados como fauna acompanhante da pesca de camarão no nordeste do Brasil RESUMO. As pescarias de arrasto são consideradas bastante eficientes na captura das espécies-alvo, porém apresentam baixa seletividade, capturando grande quantidade de fauna acompanhante. Entre as espécies capturadas, a família Sciaenidae é quase sempre dominante. A área de estudo está localizada no Estado de Pernambuco (Barra de Sirinhaém), região Nordeste do Brasil. Durante o período de agosto/11 a julho/12 foi capturado um total de 3.278 cianídeos, divididos entre 16 espécies, sendo 34,2% machos e 41,5% fêmeas. Larimus breviceps, Isopisthus parvipinnis, Paralonchurus brasiliensis e Stellifer microps foram as espécies mais abundantes. A área estudada foi considerada zona de recrutamento e reprodução, com os maiores índices de atividade reprodutiva entre os meses de dezembro/11 e julho/12. A constante captura de indivíduos maduros de I. parvipinnis e S. microps, durante todo o período de amostragem, sugere que estas espécies possuem desova múltipla e utilizam a área durante seu período reprodutivo. Devido a maioria dos indivíduos capturados como fauna acompanhante não terem alcançado sua maturidade sexual, é necessário melhor monitoramento da área estudada, assim como dos cianídeos capturados, uma vez que essa captura acidental pode causar flutuações nos processos de recrutamento, aumentando a proporção de imaturos, prejudicando, o processo reprodutivo das espécies.Palavras-chave: Demersal, arrasto, maturidade sexual, zona costeira.
The prawn fishery produces more discards than any other type of catch and captures a large quantity of immature individuals. This research aimed to assess the sustainability of capture of fish bycatch in prawn trawling. Each species was assessed according to two groups of criteria: (1) their relative vulnerability to capture by trawl and mortality due to this fishery (2) recovery capacity of the specie after a possible collapse of the population. Within each group, each species was ranked (1-3), being 1 the highest value, meaning the species is highly susceptible to capture or has a low resilience. A total of 8,894 individuals were caught, belonging to 28 families. The species with capture least sustainable were Stellifer rastrifer and Isopisthus parvipinnis. These latter species are highly susceptible since they are either benthic or demersal, and their diet may include benthic organism. Chirocentrodon bleekerianus and Anchoa tricolor were the most likely fishes to be sustainable since they are pelagic, they are least susceptible to capture by trawls, and also have a greater capacity to recover, as most individuals have bred before capture. Due to the fishery's multi-specific nature, it is difficult to implement mitigation measures for specific species. Thus, the creation of fishing exclusion zones should be considered as the most appropriate management measure.A pesca de arrasto de camarão produz mais descarte do que qualquer outra pescaria e captura uma grande quantidade de indivíduos imaturos. Esta pesquisa visa determinar a sustentabilidade da captura da ictiofauna acompanhante na pesca de arrasto de camarão. Cada espécie foi analisada de acordo com dois grupos de critérios: (1) vulnerabilidade à captura pela rede de arrasto e mortalidade ocasionada por esta pescaria; e (2) capacidade de recuperação da população para minimizar. Dentro de cada critério as espécies foram classificadas de 1 a 3, sendo 1 o valor mais alto, indicando que a espécie é altamente susceptível à captura ou tem baixa capacidade de recuperação. Um total de 8.894 indivíduos foram capturados, pertencendo a 28 famílias. As espécies com captura menos sustentável foram Stellifer rastrifer e Isopisthus parvipinnis. Estas espécies são altamente susceptíveis, pois são bentônicas ou demersais e suas dietas incluem organismos bentônicos. Chirocentrodon bleekerianus e Anchoa tricolor foram as espécies que apresentaram a captura mais sustentável. Por serem pelágicas, são menos susceptíveis à captura por arrastos de fundo, além disto, apresentaram uma grande capacidade de recuperação, pois a maior parte dos indivíduos capturados encontrava-se acima do seu tamanho de primeira maturação sexual. Devido à natureza multiespecífica da pescaria é difícil implementar medidas mitigatórias específicas. Assim, a criação de zona de exclusão de pesca deve ser considerada como a medida de manejo mais adequada.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.