- Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
- Stockholm University
Seaweed beds support more juvenile reef fish than seagrass beds in a south-western Atlantic tropical seascape
Eggertsen, L.; Ferreira, C. E. L.; Fontoura, L.; Kautsky, N.; Gullstrom, M.; Berkstrom, C.
Seascape connectivity is regarded essential for healthy reef fish communities in tropical shallow systems. A number of reef fish species use separate adult and nursery habitats, and hence contribute to nutrient and energy transfer between habitats. Seagrass beds and mangroves often constitute important nursery habitats, with high structural complexity and protection from predation. Here, we investigated if reef fish assemblages in the tropical south-western Atlantic demonstrate ontogenetic habitat connectivity and identify possible nurseries on three reef systems along the eastern Brazilian coast. Fish were surveyed in fore reef, back reef, Halodule wrightii seagrass beds and seaweed beds. Seagrass beds contained lower abundances and species richness of fish than expected, while Sargassum-dominated seaweed beds contained significantly more juveniles than all other habitats (average juvenile fish densities: 32.6 per 40 m(2) in Sargassum beds, 11.2 per 40 m(2) in back reef, 10.1 per 40 m(2) in fore reef, and 5.04 per 40 m(2) in seagrass beds), including several species that are found in the reef habitats as adults. Species that in other regions worldwide (e.g. the Caribbean) utilise seagrass beds as nursery habitats were here instead observed in Scirgassum beds or back reef habitats. Coral cover was not correlated to adult fish distribution patterns; instead, type of turf was an important variable. Connectivity, and thus pathways of nutrient transfer, seems to function differently in east Brazil compared to many tropical regions. Sargassum-dominated beds might be more important as nurseries for a larger number of fish species than seagrass beds. Due to the low abundance of structurally complex seagrass beds we suggest that seaweed beds might influence adult reef fish abundances, being essential for several keystone species of reef fish in the tropical south-western Atlantic. (C) 2017 Elsevier Ltd. All rights reserved.
Nursery grounds; Reef fish; Habitat choice; Seaweed; Ontogeny; Connectivity
Estuarine, Coastal and Shelf Science
2017, Volume: 196, pages: 97-108
Publisher: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
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