Community composition of benthic invertebrates on underwater cultural heritage and coral reefs from Palau aquired May to November 2022

Ships, planes, and other vessels that come to rest on the seafloor introduce metals to the marine environment. Underwater cultural heritage (UCH) sites become important habitats for sessile invertebrates, but the materials they are made from can impact the composition of species living on them. We collected and analyzed images from three sites in Palau (two shipwrecks and one plane wreck from WWII) along with directly adjacent (1 – 5 m away) naturally-occurring coral reefs. We collected images of the sessile invertebrate fauna at each site using a Nikon D850 camera with a wide-angle lens, a GoPro Hero 7 with a wide-angle lens, and two Olympus TG-6 cameras. Wide-angle photography was used to record adult corals or other sessile invertebrates (≤ 5 cm diameter) in quadrats (0.34 ± 0.01 m2, mean ± SE). Olympus cameras were used for macro photography of young coral recruits (< 5 cm diameter), with each recruit being photographed individually to enable identification. Images were used to visually identify and count sessile invertebrates living on each wreck and the adjacent coral reefs. Coral species were identified to the genus level by comparison to published guides. Other sessile invertebrate species were identified to broad taxonomic categories (e.g., wire coral, sponge, tube worm).