Depth and density distribution of the invasive vermetid eualetes tulipa (Rousseau in Chenu, 1843) in the southwestern tropical Atlantic

Abstract

Vermetid gastropods are geologically useful as sea-level and palaeoclimatic indicators, and are known as bioengineering species that contribute to biological diversity. Vermetids are adapted to a sessile lifestyle but can sometimes be transported to distant regions and become non-indigenous and/or invasive species. Eualetes tulipa is considered invasive in Hawaii and Venezuela, and we detected it in 2009, inside Forno Harbour (22º58′22.39″S; 42º00′49.44″W) at Arraial do Cabo, Brazil in the southwestern Atlantic. Site surveys were performed at four depths to determine their occurrence, depth distribution, and size structures, including natural and artificial substrates. A total of 494 individuals of E. tulipa were recorded in the three sites investigated, with the highest population densities found on artificial substrates (breakwater) inside the harbour (1.5 ind m-2) and at the greatest depth (4.0 ind m-2). Their size structures indicated recent introduction, with the species spreading in the Arraial do Cabo region over natural and artificial substrates.