title: The Mediterranean deep-water kelpLaminaria rodrigueziiis an endangered species in the Adriatic Sea.
abstract: Deep-water kelps are little-known large brown algae occurring close to the lower limit of photosynthetic life in the sea. This study compares historical and recent records of the deep-water Mediterranean kelpLaminaria rodrigueziiin the Adriatic Sea. Historical records include data from herbarium collections and trawling fishery expeditions in the mid-twentieth century, while recent data comprise records of the last 17 years from MEDITS expeditions, ROV surveys of historical kelp locations, benthic surveys and records by fishermen. Altogether, these findings demonstrate that the Adriatic population ofL. rodrigueziihas suffered a decline of more than 85 % of its historical range and is now present only around the small offshore island of Palagruža. Bottom trawling activities are presumably responsible for the disappearance elsewhere. We propose to classifyL. rodrigueziias "Endangered" in the Adriatic Sea under IUCN criteria B1ab(i,iii,iv), ver 3.1. Oceanographic characteristics of the habitat suggest that besides high water transparency, presence of North Adriatic Dense Water with both strong currents and stable low temperatures of around 14 °C are essential oceanographic factors for the development ofL. rodrigueziiin the Central Adriatic. The origin of cold water thus differs from that at upwelling sites permitting populations of tropical deep-water kelps. The phylogenetic position ofL. rodrigueziiis so far unknown. DNA sequences from nuclear and cytoplasmic markers of two thalli from Croatia and the western Mediterranean confirmed thatL. rodrigueziiis a member of the Laminariaceae and most closely related toL. ochroleuca,L. pallidaand the Brazilian deep-water kelpL.abyssalis.
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Ante
authors.initials: A
authors.lastname: Žuljević
authors.affiliation: Bezhin Rosko, 40 rue des pêcheurs, 29250 Santec, Brittany, France.
authors.forename: Akira F
authors.initials: AF
authors.lastname: Peters
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Vedran
authors.initials: V
authors.lastname: Nikolić
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Boris
authors.initials: B
authors.lastname: Antolić
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Marija
authors.initials: M
authors.lastname: Despalatović
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Cvitković
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Igor
authors.initials: I
authors.lastname: Isajlović
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Hrvoje
authors.initials: H
authors.lastname: Mihanović
authors.affiliation: Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia.
authors.forename: Slavica
authors.initials: S
authors.lastname: Matijević
authors.affiliation: Oceanlab, University of Aberdeen, Newburgh, AB41 6AA Scotland, UK.
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Shewring
authors.affiliation: Institute for Environmental Protection and Research ISPRA, Via Vitaliano Brancati 48, Rome, 00144 Italy.
authors.forename: Simonepietro
authors.initials: S
authors.lastname: Canese
authors.affiliation: Department of Botany, Faculty of Biology, University of Athens, Panepistimiopolis, Athens, 157 84 Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Katsaros
authors.affiliation: Oceanlab, University of Aberdeen, Newburgh, AB41 6AA Scotland, UK.
authors.forename: Frithjof C
authors.initials: FC
authors.lastname: Küpper
keywords: Bottom trawling; Circalittoral; Endangered algae; ITS; IUCN criteria; Kelp; Rubisco spacer; cox1