Population structure and conservation status of the red gorgonian Paramuricea clavata (Risso, 1826) in the Eastern Adriatic Sea |
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| Authors: | Silvija Kipson Cristina Linares Hrvoje Čižmek Emma Cebrián Enric Ballesteros Tatjana Bakran‐Petricioli Joaquim Garrabou |
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| Affiliation: | 1. Division of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia;2. Departament d'Ecologia, Universitat de Barcelona, Barcelona, Spain;3. Marine Explorers Society –“20,000 leagues”, Zadar, Croatia;4. Facultat de Ciències, Departament de Ciències Ambientals, Campus Montilivi, Universitat de Girona, Girona, Spain;5. Centre d'Estudis Avan?ats de Blanes ? CSIC, Girona, Spain;6. Institut de Ciències del Mar (ICM‐CSIC), Barcelona, Spain;7. UM110, CNRS/INSU, IRD, Aix‐Marseille Université, Université du Sud Toulon Var, Mediterranean Institute of Oceanography (MIO), Marseille, France |
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| Abstract: | Gorgonians are important structuring species of the Mediterranean hard‐bottom communities that are threatened by disturbances such as increasing seawater temperature, mucilaginous events and destructive fishing, among others. In this study we assessed for the first time the population structure and conservation status of one of the most common gorgonians in the Eastern Adriatic Sea, the red gorgonian Paramuricea clavata. During late spring 2009, nine populations dwelling between 30 and 50 m depth were examined by SCUBA diving along 200 km of the Croatian coastline. The density ranged between 7 and 20 colonies·m?2. The mean and maximum colony heights were 31.2 ± 22.7 cm (±SD) and 138 cm, respectively. Two main patterns of P. clavata size frequency distributions were observed: the first one with a higher proportion of juveniles (~30%) observed mostly in the northernmost populations, and the second one with a higher proportion of larger colonies (>25% of colonies >40 cm in height). Regarding the disturbance impact level, the proportion of healthy colonies (with <10% of injured surface) was high in almost all of the studied populations (>60%) and the mean extent of injury (i.e. denuded axis or epibiosis) was 9.7 ± 4% (±SD), indicating low impacts. Contrasting population size structures with high recruitment in mature populations provides new insights into the demographic structure of the Mediterranean gorgonian forests dwelling in their upper bathymetric range (<50 m depth). Furthermore, these size structures and the low impact levels suggest a current favorable conservation status of the studied populations in the Eastern Adriatic Sea and provide a baseline for their monitoring in the future. |
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| Keywords: | Adriatic Sea demography gorgonian octocoral
Paramuricea clavata
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