First record of Tricellaria inopinata (Bryozoa: Candidae) in the harbours of La Spezia and Olbia, Western Mediterranean Sea (Italy)

Abstract

In summer 2010, a systematic survey was carried out in the harbours of La Spezia (Ligurian Sea) and Olbia (western Tyrrhenian Sea) with the aim of studying alien species in Italian commercial harbours. Biological samples were collected by replicate scraping on the concrete walls of docks at the beginning and at the end of the summer season. Identification to species level revealed the presence of Tricellaria inopinata, an invasive alien cheilostome bryozoan of Pacific origin, first introduced to Europe in the Lagoon of Venice (Italy) in 1982. Thereafter it has been reported in other ports in Britain,

The non-indigenous Paranthura japonica Richardson, 1909 in the Mediterranean Sea: travelling with shellfish?

“…Two factors suggest aquaculture as a very likely pathway supporting the hypothesis of Venetian origin of the La Spezia and Olbia populations of P. japonica: (i) both harbours host cultures of commercial bivalves (clams, oysters, mussels) (Cannas et al, 2009;Cattaneo-Vietti et al, 2010;Doneddu, 2011;Lodola et al, 2012) and over the years some material could have been imported from Venice. Interviews with local mussel farmers in Olbia confirmed that the majority of mussel seeds were imported from the northern Adriatic lagoons (Lodola et al, 2012).…”

“…Interviews with local mussel farmers in Olbia confirmed that the majority of mussel seeds were imported from the northern Adriatic lagoons (Lodola et al, 2012). (ii) Both La Spezia and Olbia display a set of NIS in common with Venice, whose occurrence had been justified with aquaculture-mediated introductions: in La Spezia harbour, the peracarids Caprella scaura Templeton, 1836 and Paracerceis sculpta (Holmes, 1904) and the bryozoan Tricellaria inopinata d'Hondt and Occhipinti Ambrogi, 1985 (Lodola et al, 2012;Lodola, 2013); in Olbia harbour, the molluscs Arcuatula senhousia (Benson in Cantor, 1842), Rapana venosa (Valenciennes, 1846), Ruditapes philippinarum (Flassch & Leborgne, 1992), Xenostrobus securis (Lamarck, 1819), the peracarids Caprella scaura and Paracerceis sculpta and the bryozoan Tricellaria inopinata (Campani et al, 2004;Cannas et al, 2009;Doneddu, 2011;Lodola et al, 2012;Lodola, 2013). P. japonica might have followed the same "caravan" of marine NIS introduced along with commercial bivalves.…”

“…A massive seawall is located lengthwise near the mouth of the harbour, protecting the port from wave exposure. Mercantile and shipbuilding activities (both civilian and military) are centred on the old basin of the harbour, while aquaculture facilities (mussel and clam farming) are located along and near the seawall at the mouth of the harbour (Lodola et al, 2012). At the beginning of 2005, some small oyster beds were also set up in La Spezia Gulf (Cattaneo-Vietti et al, 2010).…”

Further Mediterranean expansion of the non-indigenous bryozoan <em>Celleporaria brunnea</em>: multiple records along the Italian coasts

“…index) depending on coverage: +, presence of isolated colonies; ++, a few colonies; +++, well-established colonies, and ++++, overwhelming abundance (Occhipinti-Ambrogi 1991). This approach, already tested in other studies on the artificial hard-bottom communities (Marchini et al 2004, Savini et al 2006, Lodola et al 2012) allowed us to compare the abundance of both vagile individual and colonial sessile components of the benthic fauna, whose quantitative estimation is not possible by enumeration of individuals.…”

Some Bryozoa species recently introduced into the Azores: reproductive strategies as a proxy for further spread

“…In the Venice Lagoon, it showed an invasive behaviour, with the subsequent decline of native bryozoan species. In the Atlantic, the first record dates from 1998, that is, T. inopinata in Poole Harbour, on the central southern coast of England [26], and probably representing the initial stage of a range expansion of the species along Atlantic coasts, even reaching high latitudes in northern Scotland and Norway [19,44,64].…”