Estrutura das assembleias de peixes em recifes subtropicais do Atlântico Sudoeste: diferenças entre ecossistemas rasos e mesofóticos e a influência das características do habitat
Date
2022-09-28
Authors
Fernandes, Maisha Gragnolati [UNIFESP]
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Motta, Fabio dos Santos [UNIFESP]
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Dissertação de mestrado
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Abstract
Há um grande aumento na quantidade de pesquisas sendo feitas em recifes mesofóticos tropicais e temperados. No Brasil, esses ambientes foram registrados desde o litoral amazônico até a Cadeia Vitória - Trindade, mas dados de pesca e observações in situ registram a ocorrência dessas formações ao sul do litoral paulista, que permanecem sem descrição na literatura. Existem lacunas de conhecimento sobre a importância ecológica e os serviços ecossistêmicos prestados pelos recifes mesofóticos, mas acredita-se que eles possam fornecer áreas de refúgio para espécies que habitam recifes rasos, muitas vezes ameaçados por estressores naturais e antropogênicos. Este trabalho teve como objetivo investigar a estrutura das assembleias de peixes em recifes subtropicais do Atlântico Sudoeste, buscando compreender as diferenças entre ambientes rasos (< 18m) e mesofóticos (> 18m), bem como avaliar a influência das características locais (profundidade, relevo, temperatura e regime de gestão) na abundância e distribuição das espécies. As assembleias de peixes foram amostradas através de estéreo filmagem remota subaquática com isca (estéreo-BRUV) realizadas na costa centro-sul de São Paulo. Trinta e três lançamentos de estéreo-BRUV foram realizados na primavera de 2021, sendo 15 na zona rasa e 18 na zona mesofótica. Foram registrados 1276 peixes pertencentes a 25 famílias e 66 espécies. Observou-se uma alta substituição de espécies ao longo da coluna d’água. Os grupos tróficos responderam de forma diferente às variáveis de habitat. Carnívoros, herbívoros e onívoros foram influenciados pela profundidade. A média do relevo explicou a abundância de planctívoros e invertívoros sésseis, sendo que estes últimos também responderam à profundidade. Invertívoros móveis responderam principalmente à gestão e à média do relevo. As assembleias de espécies alvo da pesca são diferentes em composição de espécies e abundância entre a zona rasa e funda, embora a biomassa foi proporcional. Os resultados não oferecem evidências de que os recifes mesofóticos do Atlântico Sudoeste subtropical atuem como refúgio para as assembleias de peixes de ambientes rasos. A profundidade, o regime de gestão e o relevo foram as principais características do habitat que influenciaram a estrutura das assembleias de peixes, uma vez que não encontramos uma relação linear entre a temperatura e os atributos da assembleia analisados.
There is a current increasing in studies in tropical and temperate mesophotic reefs. In Brazil, these environments have been recorded from the Amazon coast until the Vitória - Trindade Chain, but fishing data and in situ observations record the occurrence of these formations until the south of the São Paulo coast, which remain without description in the literature. There are knowledge gaps about the ecological importance and ecosystem services provided by mesophotic reefs, but it is believed that they can provide refuge areas for species that inhabit shallow reefs, often threatened by natural and anthropogenic stressors. This work aims to investigate and describe the vertical structure of fish assemblages in subtropical reefs of the SW Atlantic, seeking for understand the differences between shallow and mesophotic habitats, as well evaluate the influence of local characteristics (depth, relief, temperature and management) in abundance and species distribution. Reef fish assemblages were assessed using Baited Remote Underwater stereo-Videos (stereo-BRUVs) on the south-central coast of São Paulo. Thirty-three stereo-BRUV deployments were performed in spring of 2021, being 15 in the shallow zone and 18 in the mesophotic zone. 1276 fishes belonging to 25 families and 66 species were recorded. High species turnover was observed along the water column. Trophic groups responded differently to habitat variables. Carnivores, herbivores and omnivores were influenced by depth. The mean relief explained the abundance of planktivores and sessile invertivores, and the latter also responded to depth. Mobile invertivores responded mainly to management and mean relief. Assemblages of fisheries target species were different in species composition and abundance between strata, while biomass were proportional. This fact offered no evidence that mesophotic reefs act as refuges for shallow fish assemblages. Depth, management and mean relief was the main habitat characteristics influencing fish assemblages’ structure, since we did not find a linear relationship between temperature and the assemblages attributes analyzed.
There is a current increasing in studies in tropical and temperate mesophotic reefs. In Brazil, these environments have been recorded from the Amazon coast until the Vitória - Trindade Chain, but fishing data and in situ observations record the occurrence of these formations until the south of the São Paulo coast, which remain without description in the literature. There are knowledge gaps about the ecological importance and ecosystem services provided by mesophotic reefs, but it is believed that they can provide refuge areas for species that inhabit shallow reefs, often threatened by natural and anthropogenic stressors. This work aims to investigate and describe the vertical structure of fish assemblages in subtropical reefs of the SW Atlantic, seeking for understand the differences between shallow and mesophotic habitats, as well evaluate the influence of local characteristics (depth, relief, temperature and management) in abundance and species distribution. Reef fish assemblages were assessed using Baited Remote Underwater stereo-Videos (stereo-BRUVs) on the south-central coast of São Paulo. Thirty-three stereo-BRUV deployments were performed in spring of 2021, being 15 in the shallow zone and 18 in the mesophotic zone. 1276 fishes belonging to 25 families and 66 species were recorded. High species turnover was observed along the water column. Trophic groups responded differently to habitat variables. Carnivores, herbivores and omnivores were influenced by depth. The mean relief explained the abundance of planktivores and sessile invertivores, and the latter also responded to depth. Mobile invertivores responded mainly to management and mean relief. Assemblages of fisheries target species were different in species composition and abundance between strata, while biomass were proportional. This fact offered no evidence that mesophotic reefs act as refuges for shallow fish assemblages. Depth, management and mean relief was the main habitat characteristics influencing fish assemblages’ structure, since we did not find a linear relationship between temperature and the assemblages attributes analyzed.
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Citation
FERNANDES, Maisha Gragnolati. Estrutura das assembleias de peixes em recifes subtropicais do Atlântico Sudoeste: diferenças entre ecossistemas rasos e mesofóticos e a influência das características do habitat. 2022. 58 f. Dissertação (Mestrado em Biodiversidade Marinha e Costeira) - Instituto do Mar, Universidade Federal de São Paulo, Santos, 2022.