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Research article2020Peer reviewedOpen access

Altered tropical seascapes influence patterns of fish assemblage and ecological functions in the Western Indian Ocean

Chacin, D. H.; Stallings, C.D.; Eggertsen, M; Akerlund, C.; Halling, C; Berkström, Charlotte


The arrangement and composition of habitats within landscapes and fine-scale habitat characteristics influence community structure and ecological processes. These aspects can be altered by anthropogenic activities, thus influencing associated assemblages. Farming of macroalgae is a common practice in tropical settings and alters the natural composition of seascapes by introducing monoculture patches. The farmed macroalgae may also differ in palatability compared to naturally-occurring macroalgae, influencing herbivory. This study assessed how these farms may differ from natural macroalgal beds in terms of habitat heterogeneity, fish assemblages, and herbivory. We surveyed fish assemblages and deployed macroalgal assays within macroalgal beds, farms and at varying distances from these habitats near Mafia Island, Tanzania. Fish composition and herbivory differed between the habitats likely due to different macrophyte species richness, underlying hard substrate in natural macroalgal beds, and high abundance of browsers nearby the farms. Additionally, fish assemblage patterns and herbivory were not consistent across the seascapes and varied with distance from the focal habitats possibly due to the presence of other habitats. The results suggest alterations of seascapes by farming practices may have consequences on fish assemblages and the ecological functions performed, thus positioning of farms should be carefully considered in management and conservation plans.

Published in

Scientific Reports
2020, Volume: 10, number: 1, article number: 12479

    Sustainable Development Goals

    Conserve and sustainably use the oceans, seas and marine resources for sustainable development

    UKÄ Subject classification

    Agricultural Science

    Publication identifier


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