| Fishes were visually censussed along transects on back-reefs and adjacent lagoons of bank-barrier reefs at six sites on St. Croix, U.S. Virgin Islands. Fishes were recorded by size class—(<3cm), (3–5cm) and (>5cm)—on back-reef, and on 5 lagoon habitat types: patch reef, rubble, seagrass, algal plain, and sand. Densities of six taxa—Acanthurus spp (A. chirurgus and A. bahianus), Haemulon spp (all species of the Haemulon genus), Sparisoma aurofrenatum, Scarus iserti, Stegastes leucostictus, and Halichoeres bivittatus—and of all species combined were examined to determine spatial and temporal patterns of habitat use. Three patterns of habitat use were discerned: one group, exemplified by Acanthurus spp and Haemulon spp, uses lagoon patch reef and rubble as nurseries in preference to back-reef and other lagoon habitats, exhibit dramatic ontogenetic habitat shifts, and densities of adults on back-reefs were strongly related to the quality of lagoon nursery habitats; a second group, exemplified by S. leucostictus and H. bivittatus , use lagoon and back reef habitats for all life stages (settlement through adult), prefer lagoon habitats, and have less pronounced habitat shifts; in contrast, Sp. aurofrenatum and Sc. iserti preferentially use back-reef, and to a lesser extent patch reef, for all life stages. Concordance analyses indicated little influence of oceanographic processes in distributions of small fishes among sites relative to benthic processes. A pilot study to determine the feasibility of tagging juvenile Acanthurus spp in lagoon nurseries and tracking these fish over time to determine the proportion of adults on reefs that use lagoon nurseries indicated the tagging procedures were appropriate but predation rates were indeterminable due to artifacts associated with tethering. Hurricane Lenny passed St. Croix during the first year of this study, providing an opportunity to examine the effects of a natural disturbance on fishes in shallow nearshore habitats within the context of a multiple-year study. Despite extensive hurricane-associated damage to habitats at the two exposed sites, fishes seemed resistant to hurricane elms, and were more influenced by normal seasonal patterns. For species that utilize lagoons as nurseries, benthic processes must be paramount when formulating marine conservation and resource management strategies. |
