Low diversity or poorly explored? Mesophotic molluscs highlight undersampling in the Eastern Mediterranean

Paolo G. Albano, Michele Azzarone, Bruno Amati, Cesare Bogi, Bruno Sabelli, Gil Rilov

Research output: Contribution to journalArticlepeer-review


Mesophotic assemblages are the next frontier of marine exploration in the Mediterranean Sea. Located below recreational scuba diving depths, they are difficult to access but host a diverse array of habitats structured by large invertebrate species. The Eastern Mediterranean has been much less explored than the western part of the basin and its mesophotic habitats are virtually unknown. We here describe two mesophotic (77–92 m depth) molluscan assemblages at a rocky reef and on a soft substrate off northern Israel. We record 172 species, of which 43 (25%) are first records for Israel and increase its overall marine molluscan diversity by 7%. Only five of these species have been reported in recent surveys of the nearby Lebanon, suggesting that our results are robust at a broader scale than our study area and that the reported west-to-east declining diversity gradient in the Mediterranean needs a reappraisal based on proper sampling of the eastern basin. We found only four (2%) non-indigenous species, represented by seven (0.5%) specimens. These results suggest that pristine native assemblages still thrive at this depth in Israel, in contrast to the shallow subtidal heavily affected by global warming and biological invasions, calling for strong conservation actions for these valuable but vulnerable habitats.

Original languageEnglish
Pages (from-to)4059-4072
Number of pages14
JournalBiodiversity and Conservation
Issue number14
StatePublished - Dec 2020
Externally publishedYes

Bibliographical note

Funding Information:
The sorting and identification of the material was conducted during a citizen science workshop funded by the Faculty of Earth Sciences, Geography and Astronomy of the University of Vienna. Martin Zuschin offered support throughout the workshop. Bella Galil offered useful suggestions. Jan Steger and the crew of the research vessel “Mediterranean Explorer” helped during fieldwork. We thank the members of the Rilov Lab and the crew of the IOLR’s research vessel “Bat Galim” for collecting and handling the samples in Rosh Carmel. Riccardo Giannuzzi-Savelli, Rafael La Perna, Italo Nofroni, Graham Oliver, Michael Stachowitsch and Carlo Smriglio offered useful advice.

Funding Information:
Open access funding provided by Austrian Science Fund (FWF). Sampling on soft substrates was conducted in the framework of the project “Historical ecology of Lessepsian migration” funded by the Austrian Science Fund (FWF) P28983-B29 (PI: P.G. Albano). Sampling of the hard substrate was conducted in the framework of the Israeli Mediterranean monitoring program conducted by IOLR and funded by the Israeli Ministry of Environmental Protection and the Ministry of Energy. Acknowledgements

Publisher Copyright:
© 2020, The Author(s).


  • Levantine Basin
  • Mesophotic zone
  • Mollusca
  • Sponge reefs
  • Twilight zone

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation


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