Marine Biology

, Volume 149, Issue 2, pp 313–325

Diet and seasonal prey capture rates in the Mediterranean red coral (Corallium rubrum L.)


    • Alfred Wegener Institute for Polar and Marine Research
  • Sergio Rossi
    • Institut de Ciències del Mar (CSIC)
  • Jürgen Laudien
    • Alfred Wegener Institute for Polar and Marine Research
  • Lorenzo Bramanti
    • Dipartimento Etologia, Ecologia, EvoluzioneUniversity of Pisa
  • Neus Fernández
    • Institut de Ciències del Mar (CSIC)
  • Josep-Maria Gili
    • Institut de Ciències del Mar (CSIC)
  • Wolf Arntz
    • Alfred Wegener Institute for Polar and Marine Research
Research Article

DOI: 10.1007/s00227-005-0220-1

Cite this article as:
Tsounis, G., Rossi, S., Laudien, J. et al. Marine Biology (2006) 149: 313. doi:10.1007/s00227-005-0220-1


Gorgonians are passive suspension feeders, contributing significantly to the energy flow of littoral ecosystems. More than in active suspension feeders (such as bivalves, ascidians and sponges) their prey capture is affected by spatial and temporal prey distribution and water movement. Corallium rubrum is a characteristic gorgonian of Mediterranean sublittoral hard bottom communities. This study found a high variability in the annual cycle of prey capture rate, prey size and ingested biomass, compared to other Mediterranean gorgonians. Detrital particulate organic matter (POM) was found throughout the year in the polyp guts and constituted the main proportion of the diet (25–44%). Crustacean fragments and copepods (14–46%) accounted for the second major proportion, while invertebrate eggs (9–15%) and phytoplankton (8–11%) constituted the smallest part of the diet. To verify the importance of detrital POM in the energy input of this precious octocoral species, in situ experiments were carried out during the winter–spring period. The results confirm the importance of detrital POM as the main source of food for C. rubrum [0.13±0.04 μg C polyp−1 h−1 (mean±SD)]. This study also compares the prey capture rates of two colony size classes and two depth strata: Within the same patch, small colonies (<6 cm height) captured significantly more prey per polyp (0.038±0.09 prey polyp−1 h−1) than larger colonies (>10 cm high) (0.026±0.097 prey polyp−1 h−1) and showed a higher proportion of polyps containing prey (17% compared to 10%). Comparing colonies of similar size (<6 cm height) revealed that the colonies situated at 40 m depth captured significantly more prey (0.038±0.09 prey polyp−1 h−1) than the ones at 20 m (0.025±0.11 prey polyp−1 h−1). One pulse of copepods was recorded that constituted 16% of all captured prey during the 15-month period studied in one of the sampled populations. The data suggest that the variability of hydrodynamic processes may have a higher influence on the feeding rate than seasonal changes in the seston composition. The carbon ingestion combined with data on the density of the exploited population results in 0.4–9.6 mg C m−2 day−1. The grazing impact of current, heavily exploited and small-sized populations is comparable to that of larger Mediterranean gorgonians, suggesting that unexploited red coral populations may have a high impact compared with other passive suspension feeders.

Copyright information

© Springer-Verlag 2005