Long-term growth rates of four Mediterranean cold-water coral species maintained in aquaria

Growth rates of the cold-water corals (CWC)Madrepora oculata,Lophelia pertusa,Desmophyllum dianthusandDendrophyllia cornigerawere measured over 8 mo under controlled conditions (12°C in the dark, fed 5 times a week) by means of the buoyant weight technique. Additionally, linear growth rates were measured inM. oculataandL. pertusafor 2 and 1 yr, respectively. The weight measurements revealed growth rates, expressed as percent growth per day (mean ± SD), of 0.11 ± 0.04 forM. oculata, 0.02 ± 0.01 forL. pertusa, 0.06 ± 0.03 forD. dianthusand 0.04 ± 0.02 % d–1forD. cornigera. Growth inM. oculatawas significantly higher (p < 0.0001) than in the other 3 CWC species. ForM. oculataandL. pertusa, also linear growth was recorded. These values (mean ± SD) were 0.014 ± 0.007 and 0.024 ± 0.018 mm d–1forM. oculataandL. pertusa, respectively. This is the first study that compares the growth rates of 4 different CWC species under the same experimental conditions of water flow, temperature, salinity and food supply. These corals have different growth rates, both in terms of total weight increase and linear increase, and these growth rates can be related to interspecific physiological differences. Data on growth rates are essential to understand the population dynamics of CWC as well as the recovery capacity of these communities after disturbance.