Title: HAVE INVASIVE LIONFISH IMPACTED THE PULLEY RIDGE MESOPHOTIC CORAL ECOSYSTEM?

Abstract: Mesophotic coral ecosystems are deep fore-reef, low-light adapted, communities often comprised of scleractinian corals, macroalgae and sponges. At a depth of 60-80m, Pulley Ridge represents the deepest coral reef on the US continental shelf extending over 100km along the western edge of the Florida Platform. We surveyed this unique ecosystem using AUVs, ROVs, and technical diving; the reefs consist of at least 25 species of algae (~50% cover), 18 species of scleractinian corals (<1% cover), and over 50 species of sponges (1-2% cover), in addition to more than 80 species of fish. The percent cover data represent a significant loss of coral and sponges relative to surveys conducted about a decade earlier. The impacts of coral reef stressors (e.g., bleaching, disease, hurricane damage, and acidification) have not been observed on Pulley Ridge, but the invasive lionfish, Pterois volitans, was first reported on these MCEs in 2010. We observed densities as high as 6.8±3.7 lionfish m-2, typically within “grouper holes”, as well as active foraging on many species of fish. While direct comparisons of the Pulley Ridge fish populations pre- and post-lionfish need to be interpreted cautiously, there does appear to be a marked decline in several taxa. We hypothesize that the loss of coral and sponge cover, to increases in algae cover, is an indirect effect of lionfish grazing on herbivorous fishes, which releases algae from herbivory to out-compete slower growing corals and sponges.

Authors: Whitney SK, Boye LR, Woolsey M, Jarnagin R, Moore S, Slattery M

Presentation: Poster (#323)

Session: 29

Date: 06/21/16

Time: 18:15 - 19:45

Location: Poster/Exhibit Hall

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