Seasonal fluctuations and dietary analysis of fouling caprellids (Crustacea: Amphipoda) from marinas of southern Spain

Abstract

In marinas, native caprellids usually share their habitat with exotic species, and can eventually be replaced by them. The invasive Caprella scaura is spreading quickly and has successfully settled in many marinas of southern Spain, potentially threatening the native taxa. We selected two marinas (El Rompido, Huelva and La Línea, Cádiz) in which C. scaura has not yet been found, in order to explore the seasonal dynamic patterns of the resident species before the arrival of the non-native species. Sampling was carried out bimonthly from July 2010 to July 2011. Two caprellid species were recorded, Caprella dilatata and C. equilibra. In El Rompido, both caprellids were found on two substrates (the bryozoan Bugula neritina and the hydroid Ectopleura crocea), whereas in La Línea, B. neritina hosted only C. equilibra, and C. dilatata was absent. Caprella dilatata showed maximum densities in July, with a second peak of abundance in November, and was absent during the winter (January–March). Caprella equilibra showed differences in abundance patterns, body length and fecundity between the two marinas, probably due to differences in environmental measures between the marinas. The dominant component of the diet of the two species was detritus, followed by copepods, which were more abundant in specimens collected from E. crocea, suggesting the possibility of cleptocommensalist behaviour.

Key words:

• Caprella equilibra
• Caprella dilatata
• diet
• fouling caprellids
• recipient communities
• seasonality
• sedimentation

Acknowledgements

Special thanks to Ángela Saavedra and Manuel González for their help in sorting the samples. Kathryn Gavira O’Neill conducted the English revision of the manuscript, and two anonymous reviewers provided useful comments and corrections.

Editorial responsibility: Roy Kropp

Additional information

Funding

Financial support for this work was provided by the Ministerio de Economía y Competitividad (Project CGL2011-22474, internal reference 2011-707) co-financed by the ERDF, European Union, and by the Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía (Project P11-RNM-7041).