Medusae and ctenophores from the Bahía Blanca Estuary and neighboring inner shelf (Southwest Atlantic Ocean, Argentina)

An updated checklist of medusae and ctenophores is presented for the first time for the area comprised by the Bahía Blanca Estuary, the adjacent shelf El Rincón and Monte Hermoso beach, on the southwest coast of Buenos Aires province (Argentina). The area is highly productive and provides several ecosystem services including fishing and tourism. Updated information on the biodiversity of medusae and ctenophores species is essential for the study area, given that these species can affect ecosystem services. The list includes 23 hydromedusae, 3 scyphomedusae, and 3 ctenophores. Five hydromedusae (Halitiara formosa, Amphinema dinema, Aequorea forskalea, Clytia lomae and Halopsis ocellata) were firstly observed in this area. Three species of medusae, 2 hydromedusae (Olindias sambaquiensis and Liriope tetraphylla) and 1 scyphomedusae (Chrysaora lactea) pose a potential health risk, due to their toxicity to humans. Considering the size of the study area, the Bahía Blanca region has a comparatively high species richness of hydromedusae, higher than larger zones previously studied along the temperate SW Atlantic Ocean. The present report provides the baseline knowledge of gelatinous species for the Bahía Blanca region.