Preditores da abundância relativa de tubarões costeiros na região Centro-Sul de São Paulo
Data
2023-09-28
Autores
Brandão, Mariana Cesar Carvalho 
Orientadores
Motta, Fabio dos Santos
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A abundância e distribuição das espécies de tubarões em ambientes costeiros é influenciada por uma combinação de fatores ecológicos (ex. risco de predação, presença de competidores, disponibilidade de presas) e variáveis ambientais. O objetivo deste trabalho foi investigar a influência de preditores ambientais (temperatura superficial do mar e fase lunar), operacionais (profundidade) e temporais (estação e ano) na abundância de cinco espécies de tubarões (Rhizoprionodon lalandii, R. porosus, Sphyrna lewini, Carcharhinus brevipinna e C. limbatus) com base em uma série de quatro anos (2000 a 2003) de dados de captura da pesca artesanal no litoral centro-sul de São Paulo. Durante o período de estudo foram monitoradas 971 operações de pesca com emalhe de fundo. A influência das variáveis ambientais e temporais sobre a CPUE dos tubarões, divididos por estágios de maturidade, foi analisada utilizando modelos mistos aditivos generalizados (GAMM). Os preditores que mais explicaram a captura por unidade de esforço (CPUE) para neonatos de R. lalandii foram a fase lunar em conjunto com a temperatura da superfície do mar, em que a lua crescente e temperaturas mais baixas apresentaram maiores capturas. Já as outras faixas etárias da espécie tiveram mais influência da estação e profundidade, em que ambas foram mais capturadas em profundidade maiores, mas os jovens tiveram mais incidência no verão e os adultos no inverno. A abundância dos neonatos de R. porosus foi influenciada pela estação, com maior captura registrada na primavera, enquanto os jovens demonstraram ser suscetíveis tanto à estação quanto à profundidade, com maiores desembarques no verão e capturas em profundidades médias (10 a 20 m). Já a abundância de adultos apresentou correlação com a temperatura da superfície do mar, com maiores valores registrados em temperaturas de 24,5⁰C. A abundância do cação-martelo S. lewini apresentou uma relação com a estação e a profundidade para neonatos e jovens, com maior captura de ambos no verão, mas em profundidades rasas (1 – 10 m) para neonatos e médias (10 – 20 m) para jovens. A abundância do cação galha-preta C. brevipinna sofreu influência da estação e da profundidade nos neonatos, com maiores incidências dessa faixa etária no verão e em profundidades maiores (20 – 30 m). A abundância relativa do cação galha-preta salteador C. limbatus foi influenciada pela estação do ano, com a maior CPUE registrada no verão e primavera. Os preditores de abundância identificados aqui podem subsidiar futuros estudos, incluindo iniciativas de monitoramento e gestão pesqueira de tubarões em águas subtropicais do Brasil.
The abundance and distribution of shark species in coastal environments are influenced by a combination of ecological factors (e.g., predation risk, presence of competitors, prey availability) and environmental variables. The objective of this study was to investigate the influence of environmental predictors (sea surface temperature and lunar phase), operational factors (depth), and temporal variables (season and year) on the abundance of five shark species (Rhizoprionodon lalandii, R. porosus, Sphyrna lewini, Carcharhinus brevipinna, and C. limbatus) based on a four-year series (2000 to 2003) of artisanal fishing catch data in the central-southern coast of São Paulo, Brazil. During the study period, 971 bottom longline fishing operations were monitored. The influence of environmental and temporal variables on shark catch per unit effort (CPUE), divided by maturity stages, was analyzed using Generalized Additive Mixed Models (GAMM).The predictors that most explained the CPUE for neonates of R. lalandii were lunar phase in conjunction with sea surface temperature, with crescent moon and lower temperatures resulting in higher catches. Other age groups of the species were more influenced by season and depth, where both were more captured at greater depths, but juveniles were more prevalent in summer and adults in winter. The abundance of R. porosus neonates was influenced by the season, with higher catches recorded in spring, while young individuals were susceptible to both season and depth, with higher landings in summer and captures at intermediate depths (10 to 20 m). The abundance of adults correlated with sea surface temperature, with higher values recorded at 24.5°C. The abundance of the scalloped hammerhead shark S. lewini showed a relationship with season and depth for neonates and young individuals, with higher captures of both in summer, but in shallow depths (1–10 m) for neonates and intermediate depths (10–20 m) for young sharks. The abundance of the spinner shark C. brevipinna was influenced by season and depth in neonates, with higher incidences in summer and greater depths (20–30 m). The relative abundance of the blacktip shark C. limbatus was influenced by the season, with the highest CPUE recorded in summer and spring. The abundance predictors identified here can support future studies, including initiatives for monitoring and fisheries management of sharks in subtropical waters of Brazil.
The abundance and distribution of shark species in coastal environments are influenced by a combination of ecological factors (e.g., predation risk, presence of competitors, prey availability) and environmental variables. The objective of this study was to investigate the influence of environmental predictors (sea surface temperature and lunar phase), operational factors (depth), and temporal variables (season and year) on the abundance of five shark species (Rhizoprionodon lalandii, R. porosus, Sphyrna lewini, Carcharhinus brevipinna, and C. limbatus) based on a four-year series (2000 to 2003) of artisanal fishing catch data in the central-southern coast of São Paulo, Brazil. During the study period, 971 bottom longline fishing operations were monitored. The influence of environmental and temporal variables on shark catch per unit effort (CPUE), divided by maturity stages, was analyzed using Generalized Additive Mixed Models (GAMM).The predictors that most explained the CPUE for neonates of R. lalandii were lunar phase in conjunction with sea surface temperature, with crescent moon and lower temperatures resulting in higher catches. Other age groups of the species were more influenced by season and depth, where both were more captured at greater depths, but juveniles were more prevalent in summer and adults in winter. The abundance of R. porosus neonates was influenced by the season, with higher catches recorded in spring, while young individuals were susceptible to both season and depth, with higher landings in summer and captures at intermediate depths (10 to 20 m). The abundance of adults correlated with sea surface temperature, with higher values recorded at 24.5°C. The abundance of the scalloped hammerhead shark S. lewini showed a relationship with season and depth for neonates and young individuals, with higher captures of both in summer, but in shallow depths (1–10 m) for neonates and intermediate depths (10–20 m) for young sharks. The abundance of the spinner shark C. brevipinna was influenced by season and depth in neonates, with higher incidences in summer and greater depths (20–30 m). The relative abundance of the blacktip shark C. limbatus was influenced by the season, with the highest CPUE recorded in summer and spring. The abundance predictors identified here can support future studies, including initiatives for monitoring and fisheries management of sharks in subtropical waters of Brazil.
Descrição
Citação
BRANDÃO, Mariana Cesar Carvalho. Preditores da abundância relativa de tubarões costeiros na região Centro-Sul de São Paulo. 2023. 72 f. Dissertação (Mestrado em Biodiversidade Marinha e Costeira) - Universidade Federal de São Paulo, Instituto do Mar, Santos, 2023.