A new geographical record of Polycera hedgpethi Er. Marcus, 1964 (Nudibranchia: Polyceridae) and evidence of its established presence in the Mediterranean Sea, with a review of its geographical distribution

Abstract

This article reports the first record of the Nudibranch Polycera hedgpethi in the Lagoon of Venice (Italy), as well as its established presence in the Mediterranean Sea after its first record in 1986 in lake Fusaro (Naples). In less than 50 years P. hedgpethi has spread throughout the world's temperate and subtropical waters, preferring protected coastal environments and other semi-enclosed coastal water bodies such as ports, harbours and lagoons. Shipping is the most likely vector. The species distribution shows a temperate–subtropical range, at about 7–45° of latitude both North and South. Polycera hedgpethi was collected during a survey in 2009 and its presence confirmed for the following two years. All individuals collected were found attached to the bryozoan Bugula neritina, to which it is linked trophically, suggesting a determined pattern of distribution. The present finding is the northernmost record for the species.

Keywords:

• Venice Lagoon
• Nudibranch
• distribution
• alien species
• cryptogenic species

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

We are grateful for the confirmation of the identification to Prof. Riccardo Cattaneo-Vietti (Dip.Te.Ris., Università di Genova, Italy), Dr Gary McDonald (Long Marine Lab, Santa Cruz, CA), and Dr Nerida Wilson (The Australian Museum, Sydney, Australia). Water temperature and salinity data were provided by Venice Water Authority. Thanks are due to Filippo Ioni and Stabellini Michele (Gian Neri Diving Club Rimini, Italy) for the 2005 report from Ravenna (Italy). A special thanks to Dr Jim Lowry for his support (The Australian Museum, Sydney, Australia). Last but not least, we are thankful to two anonymous referees who helped to improve the paper.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark