Marine alien species as an aspect of global change

The transport of organisms across oceans is an anthropogenic agent of global change that has profoundly affected the natural distribution of littoral biota and altered the makeup of biogeographic regions. The homogenization of marine biotas is a phenomenon especially affecting coastal regions and is spearheaded by a suite of opportunistic species at the expense of native species. Climate change may exacerbate the trend: sea surface temperatures, hydrodynamics, pH and carbonate cycles, already show marked fluctuations compared to the past. Alien invasive species are impacted by the change of marine climate in a variety of ways, which are we have just begun to notice, observe and interpret. A conceptual framework has yet to be conceived that links theories on biological introductions and invasions with the physical aspects of global change. Therefore predicting the scale of invasions or their impact on biodiversity is a daunting task. Integration of biological and environmental information systems, niche models, and climate projections would improve management of aquatic ecosystems under the dual threats of biotic invasions and climate change. The recorded spread of alien species and analysis of patterns of invasions may serve as the starting point for searching connections with climate change descriptors. The Mediterranean Sea is home to an exceptionally large number of alien species, resulting from its exceptional history and multiple vectors. For much of the twentieth century alien thermophilic species, which had entered the Mediterranean through the Suez Canal, have been confined to the Levantine Basin. In recent years climate driven hydrographic changes have coincided with a pronounced expansion of alien thermophilic biota to the central and western basins of the Mediterranean. We discuss some changes in emergent functions and services in Mediterranean ecosystems under the combined effect of invasive species and climate changes

The northernmost record of the blue-spotted cornetfish from the Mediterranean Sea

A school of Fistularia commersonii was sighted off Laigueglia (Italy), Northwestern Ligurian Sea, inAugust 2008. This fast spreading invasive Indo-Pacific fish was first recorded in the Mediterranean fromIsrael, and it has since spread clear across the sea. This is the northernmost record from the Mediterranean

Potvrda predviđanja: venecijanska laguna (Italija) obiluje invazivnim jednakonošcem Ianiropsis serricaudis Gurjanova, 1936 (Crustacea: Peracarida)

The janirid isopod Ianiropsis serricaudis, native to the North-West Pacific region, has recently been identified as a non-indigenous species in several localities in the Northern Hemisphere. Hereby, we present evidence of its occurrence in the Mediterranean Sea, namely in the Lagoon of Venice (Italy). This finding confirms the hypothesis that this species is more widespread in Europe than expected, but has long been underreported on account of the small size of isopods (most of them being in the size range of 3 to 20 mm) and the taxonomic complexity of the genus.Janiridni jednakonošci Ianiropsis serricaudis, koji izvorno potječu iz sjeverozapadne pacifičke regije, nedavno su identificirani kao alohtona vrsta na nekoliko lokaliteta u sjevernoj hemisferi. Ovime iznosimo dokaze o njihovom pojavljivanju u Sredozemnom moru, i to u venecijanskoj laguni (Italija). Ovi nalazi potvrđuju tezu da je ova vrsta rasprostranjenija u Europi nego što se mislilo, ali se o njoj dugo vremena malo izvješćivalo zbog veličine jednakonožaca (većina je veličinom varirala između 3 i 20 mm) te zbog taksonomske složenosti roda

Potvrda predviđanja: venecijanska laguna (Italija) obiluje invazivnim jednakonošcem Ianiropsis serricaudis Gurjanova, 1936 (Crustacea: Peracarida)

The janirid isopod Ianiropsis serricaudis, native to the North-West Pacific region, has recently been identified as a non-indigenous species in several localities in the Northern Hemisphere. Hereby, we present evidence of its occurrence in the Mediterranean Sea, namely in the Lagoon of Venice (Italy). This finding confirms the hypothesis that this species is more widespread in Europe than expected, but has long been underreported on account of the small size of isopods (most of them being in the size range of 3 to 20 mm) and the taxonomic complexity of the genus.Janiridni jednakonošci Ianiropsis serricaudis, koji izvorno potječu iz sjeverozapadne pacifičke regije, nedavno su identificirani kao alohtona vrsta na nekoliko lokaliteta u sjevernoj hemisferi. Ovime iznosimo dokaze o njihovom pojavljivanju u Sredozemnom moru, i to u venecijanskoj laguni (Italija). Ovi nalazi potvrđuju tezu da je ova vrsta rasprostranjenija u Europi nego što se mislilo, ali se o njoj dugo vremena malo izvješćivalo zbog veličine jednakonožaca (većina je veličinom varirala između 3 i 20 mm) te zbog taksonomske složenosti roda

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

In the framework of a wider systematic survey aimed at studying non-indigenous species in Italian harbours and marinas, the ascophoran bryozoan Celleporaria brunnea was detected for the first time in the western Mediterranean Sea. The species is presumably native to the Pacific coasts of North America and is distributed from British Columbia to the Galapagos Islands (Ecuador). In the Mediterranean Sea, C. brunnea was first recorded in 2004 in the inner part of Izmir Bay near Alsancak harbour (Turkey) and later reported along the Lebanese coasts. The species was recently detected in Cascais marina in Portugal and in the Arcachon Basin (France), documenting the first records in the eastern Atlantic. The finding in the Italian harbours of La Spezia (Liguria), Olbia (Sardinia) and Lampedusa (off Sicily) marks its western and northernmost occurrence within the Mediterranean basin. Pathways of introduction into the western Mediterranean Sea are discussed, concluding that hull fouling is the most likely vector. The species may be expected to appear soon in other harbours of the Mediterranean basin

Effect of Predation on Fouling Communities in an Italian Hotspot of Non-Indigenous Species

The role of native predators in controlling or facilitating non-indigenous species (NIS) growing in a fouling assemblage was investigated with a 70-day caging experiment in a marina inside the Gulf of La Spezia (Italy). Submerged PVC panels were divided into three experimental treatment levels: “control panels”, “open-caged panels” and “caged panels”, to assess the predation effect on the fouling assemblages growing on the panels. Predation effect was observed for two investigated variables. The Shannon Index was significantly higher in caged panels in comparison with controls, while an opposite trend was observed for the coverage area of native species. When testing single NIS abundance, both facilitation and limitation of individual NIS settlement has been observed. Mean coverage of the sabellid Branchiomma luctuosum was significantly higher in caged than in uncaged or open-caged panels, while the ascidian Styela plicata was prevalent in open-caged panels. In general, a predation effect was observed when considering the whole fouling assemblage, including different trends in NIS coverage among treatment levels. The results of this first attempt performed in the Mediterranean Sea encourage further experiments to investigate the biotic resistance provided by native predators against NIS

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

An anthurid isopod new to the Mediterranean Sea has recently been observed in samples from three localities of the Italian coast: the Lagoon of Venice (North Adriatic Sea), La Spezia (Ligurian Sea) and Olbia (Sardinia, Tyrrhenian Sea). The specimens collected showed strong affinity to a species originally described from the NW Pacific Ocean: Paranthura japonica Richardson, 1909. The comparison with specimens collected from the Bay of Arcachon (Atlantic coast of France), where P. japonica had been recently reported as non-indigenous, confirmed the identity of the species. This paper reports the most relevant morphological details of the Italian specimens, data on the current distribution of the species and a discussion on the pathways responsible for its introduction. The available data suggest that the presence of this Pacific isopod in several regions of coastal Europe might be due to a series of aquaculture-mediated introduction events that occurred during the last decades of the 1900s. Since then, established populations of P. japonica, probably misidentified, remained unnoticed for a long time

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

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Esperimento di rimozione degli ammassi mucillaginosi della microalga alloctona <i>Chrysophaeum taylorii</i> Lewis &amp; Bryan = Experiment of removal of the mucilaginous aggregates by the alien microalga <i>Chrysophaeum taylorii</i> Lewis &amp; Bryan

A manipulative experiment was carried out in a small bay of Tavolara Punta Coda Cavallo Marine Protected Area in order to investigate the triggers for formation and storage of the macroscopic mucilaginous aggregates of the benthic microalga Chrisophaeum taylorii Lewis &amp; Bryan (Pelagophyceae) and to test the efficacy of mucillage removal