Influence of fouling communities on the establishment success of alien caprellids (Crustacea: Amphipoda) in Southern Spain

Abstract

Recently, two non-native caprellid amphipods, Caprella scaura and Paracaprella pusilla, were found for the first time in southern Spain. In order to assess their establishment success, monitoring of the caprellid fauna associated with the marina's fouling community was carried out from summer 2010 to spring 2011 in Cádiz marina, southern Spain. Three caprellid species were found, the non-native C. scaura and P. pusilla, and the native Caprella equilibra. Caprella scaura was the dominant species with ovigerous females and juveniles throughout the whole study period, reflecting both that it reproduces all year around and that it is able to support the differences measured in water temperature, salinity and turbidity among seasons. It showed a high ability to colonize different fouling substrates, although it was significantly more abundant in the introduced bryozoan Bugula neritina. The tropical caprellid P. pusilla was found in lower abundance than C. scaura as it only was present in summer, associated exclusively with the native hydroid Eudendrium racemosum. The native C. equilibra, very common in other nearby harbours where alien caprellids were absent, was scarcely represented in the study area. The results suggest first that P. pusilla is an introduced species with less invasiveness than C. scaura, and second, that fouling bryozoans, especially B. neritina, are suitable habitat for the establishment success of C. scaura, harbouring high densities of this invasive species, while fouling hydroids, particularly in the case of the native hydroid E. racemosum, are more suitable for the establishment success of P. pusilla.

Keywords:

• Introduced caprellids
• Caprella scaura
• Paracaprella pusilla
• invasiveness
• facilitation

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

The authors would like to thank Elena Baeza-Rojano, Carlos Navarro and Pilar Cabezas for their assistance during sampling. We also wish to thank the staff of the Cádiz Marina for their courtesy in allowing us to use their facilities for our research and the anonymous reviewers for their valuable comments and suggestions to improve the manuscript. This work was funded by a predoctoral grant from the Spanish Ministery of Education (Reference AP-2009-3380) and by the project CGL2011-22474 co-financed by FEDER funds.

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