Seasonal patterns in the abundance of Ectopleura crocea (Cnidaria: Hydrozoa) on a shipwreck in the Northern Adriatic

Abstract

Ectopleura crocea is an Anthomedusan hydroid, frequently recorded and abundant on artificial substrates. Here we examine whether the abundance of this species varies seasonally on a shipwreck in the Northern Adriatic at a depth of 10–12 m. Individuals were first found in late autumn when temperatures had dropped below 15 °C, forming scattered colonies composed of a few, small hydranths bearing immature gonophores. Substratum cover and density increased throughout late winter and spring, reaching a peak in April. At temperatures of about 19 °C, colonies were no longer present in June and remained absent throughout the summer. The polyp gut contents comprised mostly crustaceans.

Macrobenthic colonization on the derelict Fisheries Vessel Khronometer, Cristo Rey Submarine Park, Argentina

“…The tubularid Ectopleura crocea in particular, is a typical fouling species commonly colonizing submerged artificial substrates, such as shipwrecks (Genzano et al, ; Zintzen et al, ). The actinula larvae presumably prefer to settle on these artificial substrates rather than the parental hydrocauli because of a more attractive microbial biofilm on the wreck's surface (Di Camilo et al, ). In neighboring rocky inter‐tidal areas, large colonies composed of numerous unbranched hydrocauli provide a suitable substrate for many associated species (Genzano, ).…”

Foreword to the Hydrozoan Society 7th Workshop Proceedings

“…determination of the trophic selectivity of small hydromedusae in the White Sea (Prudkovsky ), the reproductive features of milleporid fire corals at coral reefs in the Indian Ocean, and the seasonal life cycle of a key tubulariid species, Ectopleura crocea , in the Adriatic Sea (Di Camillo et al . );…”

“…), Central Mediterranean (Soto and Peña Cantero ), Arctic coastal waters (Ronowicz et al . ); careful re‐descriptions of the siphonophores Dromalia alexandri (Mapstone & Ljubenkov ) and of the physonect post‐larval stage known as Mica micula (Grossmann et al . ), which will represent taxonomic baselines for future studies on these delicate hydrozoans; analysis of taxonomical uncertainties (Stepanjants & Svoboda ) or competitive species interactions (Batistić et al .…”

“…); determination of the trophic selectivity of small hydromedusae in the White Sea (Prudkovsky ), the reproductive features of milleporid fire corals at coral reefs in the Indian Ocean, and the seasonal life cycle of a key tubulariid species, Ectopleura crocea , in the Adriatic Sea (Di Camillo et al . ); biogeographical assessment of the benthic hydroid assemblage across the Atlantic‐Mediterranean boundary (González‐Duarte et al . ), or an historical and biogeographical analysis of the current status of hydrozoan species richness in the Mediterranean Sea, with an update on the occurrence of non‐indigenous species (Gravili et al .…”

“…careful re‐descriptions of the siphonophores Dromalia alexandri (Mapstone & Ljubenkov ) and of the physonect post‐larval stage known as Mica micula (Grossmann et al . ), which will represent taxonomic baselines for future studies on these delicate hydrozoans;…”