Biology and new records of the invasive species Branchiomma bairdi (Annelida: Sabellidae) in the Mediterranean Sea

Abstract

The first observations on the reproductive biology of the alien polychaete Branchiomma bairdi (McIntosh, 1885) (Sabellidae) in the Mediterranean Sea are provided as well as additional Mediterranean records of the species, which can help to understand its introduction and spreading. Re-examination of the specimens from Miseno harbour (Tyrrhenian Sea, Italy) revealed the presence of B. bairdi in the central-Mediterranean since September 2004. The histological study of individuals collected in Malta revealed that the species is a simultaneous hermaphrodite, developing male and female gametes in the same body segments; embryos are brooded inside the parent tube. However, there is also evidence of asexual reproduction. The species shows a different reproductive pattern from the previously reported population from the eastern-Pacific; this demonstrates its great plasticity and adaptability. Branchiomma bairdi has an invasive behaviour, colonizing large areas in relatively short-time, and reaching relatively high densities (c.a. 50 individuals/m 2 ). Its expansion to several Mediterranean localities is largely a consequence of the high capacity of this species to colonize extremely different habitats and substrates, the occurrence of sexual and asexual reproductive strategies, and the combination of both. Furthermore, B. bairdi appears to be particularly abundant in confined areas and areas degraded due to anthropogenic impacts. Finally, our findings strongly suggest that the pathway of introduction in the Mediterranean, previously hypothesized as the Suez Canal (Lessepsian migration), is most likely via the Strait of Gibraltar.

A taxonomic guide to the fanworms (Sabellidae, Annelida) of Lizard Island, Great Barrier Reef, Australia, including new species and new records

“…In this framework, the relevance of the finding of the introduced species Branchiomma bairdi in Lizard Island is highlighted. This species was originally described originally from the Caribbean (McIntosh 1885) and recently reported in the Gulf of California, the Mediterranean, the Canary Islands and Portugal (Çinar 2009;Tovar-Hernández et al 2009a, b, 2011Zenetos et al 2010;Giangrande et al 2012;Arias et al 2013;Ramalhosa et al 2014) but had also previously been reported in Heron Island, Queensland (Capa et al 2013). Although it is considered as an occasional species in Australia (and probably should be considered as introduced at this point), densities measured of populations outside the natural distribution range reach up to 18000 ind/m 2 in the Gulf of California .…”

“…Branchiomma bairdi is distinguished from other congeners by the presence of strap-like and long macrostylodes (up to four times the length of the neighbouring digitiform stylodes, not so large in small specimens), and the colour pattern, with olive-green bodies and conspicuous bright orange spots alternating with radiolar eyes. This species was originally described from the Caribbean but has recently been reported is other biogeographical areas as an invasive species (Tovar-Hernández et al 2009Arias et al 2013;Capa et al 2013;Capa 2014). First record from Lizard Island.…”

The Mediterranean non-indigenous ascidian Polyandrocarpa zorritensis : Microbiological accumulation capability and environmental implications

“…The hypothesis to employ an alien species as bioremediator was already suggested by Stabili et al, (2014) for another alien filter feeder species, the polychaete Branchiomma bairdi (Sabellidae) which is a Caribbean species recently introduced in several Mediterranean localities (Arias et al, 2013). Both P. zorritensis and B. bairdi show a high capacity to colonize extremely different habitats and substrates, appearing particularly abundant in confined environments and harbors (Arias et al, 2013;Brunetti and Mastrototaro, 2004;Stabili et al, 2014).…”

“…Both P. zorritensis and B. bairdi show a high capacity to colonize extremely different habitats and substrates, appearing particularly abundant in confined environments and harbors (Arias et al, 2013;Brunetti and Mastrototaro, 2004;Stabili et al, 2014). These two alien filter feeders at present are the only investigated on account of their microbiological accumulation capability.…”

“…The rate of biological invasions has increased in recent decades, and collectively they have significant ecological and economic impacts on the Mediterranean Sea (Galil, 2000;Katsanevakis et al, 2014). The invasive species established in the Mediterranean include several benthic filter-feeders such as ascidians, polychaetes, sponges and bivalves which are introduced within fouling communities (Arias et al, 2013;Zenetos et al, 2012). As a consequence, the fouling community of the Mediterranean area results at present highly dominated by alien taxa .…”