Abstract

Coastal mangroves in the Caribbean are typically connected to adjacent habitat types through the movements of fish. Understanding the distribution of fish in mangroves therefore requires consideration of the surrounding seascape. This research adopts a multiscale seascape approach to examine the spatial distribution of juvenile fish in a mangrove lined bay in the U.S. Virgin Islands. We sampled fish from the mangrove fringe using fish traps at 12 random locations. The seascape was mapped for the entire bay from high resolution aerial photography and field validation. Seascape composition was quantified from the habitat map at a range of scales surrounding each sample location using geographical information system tools. Within the bay, the site-to-site differences in the amount of mangrove were insignificant. Instead, structurally heterogeneous seascapes containing mangroves with adjacent dense seagrass and macroalgae in close proximity to coral reefs had significantly higher fish species richness and abundance of juvenile fish. Lowest richness and abundance were characteristic of mangroves with low seagrass cover in adjacent areas and high cyanobacterial cover associated with the inner bay. Similarly, juvenile Haemulon flavolineatum (French grunt), Ocyurus chrysurus(yellowtail snapper) and Lutjanus apodus (schoolmaster snapper) were most abundant at mangrove fringe with a high percent cover of macroal-gae (~40%) and seagrass (~10%) proximal to coral reefs than in seascapes dominated by cyanobacteria. In con-trast, Eucinostomus melanopterus (flagfin mojarra) and Spheroides testudineus (checkered puffer)were more abundant in seascapes with high cyanobacteria cover and low macroalgal and seagrass cover, farthest from coral reef.

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