Fish assemblage of the Mamanguape Environmental Protection Area, NE Brazil: abundance, composition and microhabitat availability along the mangrove-reef gradient

Abstract

Reefs, mangroves and seagrass biotopes often occur in close association, forming a complex and highly productive ecosystem that provide significant ecologic and economic goods and services. Different anthropogenic disturbances are increasingly affecting these tropical coastal habitats leading to growing conservation concern. In this field-based study, we used a visual census technique (belt transects 50 m x 2 m) to investigate the interactions between fishes and microhabitats at the Mamanguape Mangrove-Reef system, NE Brazil. Overall, 144 belt transects were performed from October 2007 to September 2008 to assess the structure of the fish assemblage. Fish trophic groups and life stage (juveniles and adults) were recorded according to literature, the percent cover of the substrate was estimated using the point contact method. Our results revealed that fish composition gradually changed from the Estuarine to the Reef zone, and that fish assemblage was strongly related to the microhabitat availability, as suggested by the predominance of carnivores at the Estuarine zone and presence of herbivores at the Reef zone. Fish abundance and diversity were higher in the Reef zone and estuary margins, highlighting the importance of structural complexity. A pattern of nursery area utilization, with larger specimens at the Transition and Reef Zone and smaller individuals at the Estuarine zone, was recorded for Abudefduf saxatilis, Anisotremus surinamensis, Lutjanus alexandrei, and Lutjanus jocu. Our findings clearly suggests ecosystem connectivity between mangrove, seagrass and reef biotopes, and highlighted the importance of Mamanguape Mangrove-Reef System as a priority area for conservation and research, whose habitat mosaics should be further studied and protected.<br>Recifes, manguezais e bancos de fanerógamas marinhas são biótopos frequentemente associados, formando um ecossistema complexo e altamente produtivo que proporciona significativos bens e serviços ecológicos e econômicos. Diferentes impactos antrópicos estão crescentemente afetando esses habitats costeiros tropicais, trazendo preocupações acerca de sua conservação. Neste estudo de campo, utilizamos uma técnica de censo visual subaquático (transecções de 50 x 2 m) para investigar as interações entre os peixes e microhabitats no complexo estuarino-recifal de Mamanguape, no Nordeste do Brasil. Entre outubro de 2007 e setembro de 2008 foram realizadas 144 transecções para avaliar a estrutura da assembleia de peixes. Grupos tróficos e estágios de vida dos peixes (jovens e adultos) foram registrados segundo a literatura, enquanto a porcentagem de cobertura do substrato foi estimada através do método de pontos de contato. Nossos resultados mostraram que a composição da ictiofauna mudou gradualmente da Zona Estuarina para a Zona Recifal, e que a assembleia de peixes esteve fortemente relacionada com a disponibilidade de microhabitats - como sugerido pela predominância de carnívoros na zona estuarina e presença de herbívoros na zona recifal. A abundância e diversidade de ...

Fish assemblages along a morphodynamic continuum on three tropical beaches

“…Furthermore, the small size of the individuals increases their agility in shallow coastal water connectivity between the fish assemblage. This connectivity between beaches and estuarine environments has been described for subtropical environments (Monteiro-Neto et al, 2008) for species of Clupeiformes, and also in a study by Xavier et al (2012) that observed connectivity between reef systems and mangroves within the same study area.…”

Trophic relationships among fish assemblages on a mudflat within a Brazilian Marine protected area

“…We include numerically dominant, commercially valuable, and ecologically important species in the Mamanguape river estuary (XAVIER et al, 2012;PESSANHA, 2014). To remove the stomach of each captured specimen, an incision was made in the abdominal region, from the anus toward the head.…”

“…The beach is greatly influenced by the entrance of ocean waters, where marine sediments are regularly exposed and submerged by tidal action, and has a maximum depth of 4 m. The tidal mudflat examined is a non-vegetated area with a gentle slope and fine muddy sediment in the intertidal zone; in the subtidal zone, seagrass, sessile invertebrates, macroalgae, mangrove leaves, and fallen branches form the benthic cover (XAVIER et al, 2012).…”

Diet and trophic organization of the fish assemblage from the Mamanguape River Estuary, Brazil

“…There is an extensive sandstone reef belt adjacent to the estuary (Silva, 2002) that becomes partially exposed during low tides, revealing an extremely complex plateau, forming tide pools (Xavier et al, 2012).…”

“…This finding may be explained by the high abundance of algae in the area, as the chain of sandstone reefs functions as a substrate for macroalgae (Xavier et al, 2012). Herbivorous species may also play a key role in the control of macroalgae proliferation (Mumby et al, 2006;Silva et al, 2014) and are considered important and abundant species in reef ecosystems (Randall, 1965;Francini-Filho et al, 2010).…”