Distribution of the Invasive Caprellid Caprella scaura (Crustacea: Amphipoda) in Cádiz Marina, Southern Spain: Implications for its Dispersal

Abstract

The invasive caprellid Caprella scaura Templeton, 1836 is rapidly spreading along marinas of Southern Spain, becoming one of the dominant species of the macrofoulers associated to bryozoans and hydroids of communities in harbours. In order to explore the abundance and distribution patterns of the species in the different habitats available in marinas (floating pontoons, buoys and hull boats), a spatial study was conducted in Cadiz Marina (Puerto America) during two sampling periods (July and November). The bryozoan Bugula neritina was present in all the habitats and were selected as a substrate for comparison among habitats. In the floating pontoons, the single species C. scaura represented more than 60% of all the epifaunal individuals (including other crustaceans, polychaetes, molluscs and pycnogonids), both in July and November. In the boats and the buoys, C. scaura was dominant also in November, while gammarideans dominated in July. Abundance of C. scaura was significantly higher in floating pontoons than in hull boats. The attached caprellids to the boats are frequently exposed to strong water currents originated by boat displacements during local trips, so the results of the present study seem to indicate a preference of C. scaura by more stable substrates and non-exposed waters within the marina, such as floating pontoons.