Jasmine Ferrario

Role of commercial harbours and recreational marinas in the spread of non-indigenous fouling species

Abstract The role of commercial harbours as sink and source habitats for non-indigenous species (NIS) and the role of recreational boating for their secondary spread were investigated by analysing the fouling community of five Italian harbours and five marinas in the western Mediterranean Sea. It was first hypothesised that NIS assemblages in the recreational marinas were subsets of those occurring in commercial harbours. However, the data did not consistently support this hypothesis: the NIS pools of some marinas significantly diverged from harbours even belonging to the same coastal stretches, including NIS occurring only in marinas. This study confirms harbours as hotspots for marine NIS, but also reveals that numbers of NIS in some marinas is higher than expected, suggesting that recreational vessels effectively facilitate NIS spread. It is recommended that this vector of NIS introduction is taken into account in the future planning of sustainable development of maritime tourism in Europe.

The global invader Paracerceis sculpta (Isopoda: Sphaeromatidae) has extended its range to the Azores Archipelago

The occurrence of Paracerceis sculpta (Holmes, 1904) in the Macaronesia biogeographical region is reported for the first time. This isopod, native from the northeastern Pacific region, has probably been transported as hull fouling, hiding in either niche areas of vessels or associated with fouling bryozoans. Specimens of P. sculpta were collected from bryozoans or other fouling organisms colonizing the marina structures. From the three distinct sexually mature male morphs of P. sculpta, only the larger was found, confirming the absence of the two smaller male morphs in an introduced population. Paracerceis sculpta is the first non-indigenous marine isopod reported in the Azores Archipelago. Environmental impacts on non-indigenous areas for this isopod are unknown; nevertheless, the occurrence of P. sculpta in the Azores Archipelago corresponds to the link between both sides of the Atlantic Ocean and is evidence of the ongoing processes of biotic homogenization of marine communities on a global scale.

A massive update of non-indigenous species records in Mediterranean marinas

The Mediterranean Sea is home to over 2/3 of the world’s charter boat traffic and hosts an estimated 1.5 million recreational boats. Studies elsewhere have demonstrated marinas as important hubs for the stepping-stone transfer of non-indigenous species (NIS), but these unique anthropogenic, and typically artificial habitats have largely gone overlooked in the Mediterranean as sources of NIS hot-spots. From April 2015 to November 2016, 34 marinas were sampled across the following Mediterranean countries: Spain, France, Italy, Malta, Greece, Turkey and Cyprus to investigate the NIS presence and richness in the specialized hard substrate material of these marina habitats. All macroinvertebrate taxa were collected and identified. Additionally, fouling samples were collected from approximately 600 boat-hulls from 25 of these marinas to determine if boats host diverse NIS not present in the marina. Here, we present data revealing that Mediterranean marinas indeed act as major hubs for the transfer of marine NIS, and we also provide evidence that recreational boats act as effective vectors of spread. From this wide-ranging geographical study, we report here numerous new NIS records at the basin, subregional, country and locality level. At the basin level, we report three NIS new to the Mediterranean Sea (Achelia sawayai sensu lato, Aorides longimerus, Cymodoce aff. fuscina), and the re-appearance of two NIS previously known but currently considered extinct in the Mediterranean (Bemlos leptocheirus, Saccostrea glomerata). We also compellingly update the distributions of many NIS in the Mediterranean Sea showing some recent spreading; we provide details for 11 new subregional records for NIS (Watersipora arcuata, Hydroides brachyacantha sensu lato and Saccostrea glomerata now present in the Western Mediterranean; Symplegma brakenhielmi, Stenothoe georgiana, Spirobranchus tertaceros sensu lato, Dendostrea folium sensu lato and Parasmittina egyptiaca now present in the Central Mediterranean, and W. arcuata, Bemlos leptocheirus and Dyspanopeus sayi in the Eastern Mediterranean). We also report 51 new NIS country records from recreational marinas: 12 for Malta, 10 for Cyprus, nine for Greece, six for Spain and France, five for Turkey and three for Italy, representing 32 species. Finally, we report 20 new NIS records (representing 17 species) found on recreational boat-hulls (mobile habitats), not yet found in the same marina, or in most cases, even the country. For each new NIS record, their native origin and global and Mediterranean distributions are provided, along with details of the new record. Additionally, taxonomic characters used for identification and photos of the specimens are also provided. These new NIS records should now be added to the relevant NIS databases compiled by several entities. Records of uncertain identity are also discussed, to assess the probability of valid non-indigenous status.

From the Pacific Ocean to the Mediterranean Sea: Watersipora arcuata, a new non-indigenous bryozoan in Europe

Abstract This study reports the first record of the cheilostome bryozoan Watersipora arcuata in the Mediterranean Sea, namely in a marina of the Ligurian Sea (Italy), during two monitoring surveys carried out in 2013 and 2014, representing to date the first European finding. The species, whose native origin is deemed to be the Tropical Eastern Pacific region, was already reported as being introduced to California, Australia, New Zealand and Hawaii, but not outside the Pacific Ocean. The genus Watersipora includes 13 species of encrusting bryozoans, difficult to distinguish using simple visual clues and usually requiring careful morphological measurements, with appropriate microscopy methods. A detailed taxonomic description of W. arcuata is provided here, in comparison with the similar species W. nigra and W. platypora.

Rapid assessment of marine non-indigenous species on mooring lines of leisure craft: new records in Croatia (eastern Adriatic Sea)

Leisure-craft mooring lines were surveyed in six berthing areas along the Croatian coast during June 2014. The aim of this study was to investigate the presence of non-indigenous species (NIS) on mooring lines known as ‘lazy’ lines. Four NIS were observed during the survey: the tunicate Styela plicata, the serpulid Hydroides elegans and two bryozoans, Celleporaria brunnea, and Amathia verticillata. Three cryptogenic species were also found during the survey: the amphipod Elasmopus rapax, the barnacle Amphibalanus amphitrite, and the bryozoan Watersipora subtorquata. Styela plicata, C. brunnea, and W. subtorquata represent the first records for Croatia. Furthermore, C. brunnea and W. subtorquata are new to the whole Adriatic Sea. All NIS and cryptogenic species were recorded in Biograd na Moru. In addition, S. plicata was also recorded in Zadar. The use of ‘lazy’ lines proved to be a rapid and effective method for recording sessile species and monitoring NIS presence. This method could be undertaken for regular NIS surveys of leisure-craft berthing areas.

Arrival of the invasive amphipod Grandidierella japonica to the Mediterranean Sea

BackgroundIn the marine environment, shipping is globally acknowledged as the major vector of introduction of organisms outside their native range. We surveyed harbours and marinas in the Western Mediterranean Sea for occurrence of non-indigenous species.ResultsMore than 200 specimens of the Japanese amphipod Grandidierella japonica were collected in 2013 from the docks of the marina of Viareggio (Tuscany, Tyrrhenian Sea). This is the first record of this species for the Mediterranean Sea.ConclusionsG. japonica was previously introduced elsewhere by oyster trade and shipping; in the case of Viareggio, where no aquaculture facilities or international shipping occur, recreational boating is the only likely vector of introduction. In Europe, G. japonica is currently confined by a few localities, mainly estuaries, enclosed bays and brackish water areas, but its successful history of invasion in the Pacific coasts of North America suggests that a further spread can be expected in the Mediterranean Sea as well.

A fuzzy ‘boater’ model to detect fouling and spreading risk of non-indigenous species by recreational boats

Recreational boating is an unregulated and underestimated vector of spread of non-indigenous species (NIS) in marine environments. The risk of a single boat to spread NIS depends not only on the local environmental context, but also on the type of boat and on the boat owners behaviour (hull cleaning and painting frequency, travel history). In this paper we present a model to assess the risk of fouling and spreading of NIS and its application to data derived from a questionnaire given to Italian boat owners. The model uses a two-levels fuzzy logic approach: (1) the first level assesses the risk of hull fouling and risk of spreading separately; (2) the second level combines the two separate risks in an overall index ranging from 0 (null risk) to 100 (highest risk) and measures the global risk of NIS introduction and spread through recreational boating. The questionnaire and the fuzzy model allow for a simple and rapid assessment of boats most likely to be infested. The proposed fuzzy model can be easily edited and adapted to context-specific ecological and social conditions. The results of this Italian study showed that 53.9% of the respondents were in the very-low and low risk categories, and 46.1% in the medium, high and very-high risk categories. Possible associations between some boaters habits and the fouling and spreading risk were explored using logistic regression analyses. The results indicate a high-risk profile of boat owner as an experienced sailor who visits many marinas during the summer season. Biosecurity guidelines, containment measures and awareness raising programmes should be implemented to prevent and avoid further spread of NIS in marine environments, and such management actions would benefit from the early detection of high-risk boats, and from the identification of profiles of boaters upon which these initiatives should be prioritized.

Mediterranean non-indigenous bryozoans: an update and knowledge gaps

This paper provides an inventory of non-indigenous bryozoan species (NIB) recorded in the Mediterranean Sea. Taking into account previous NIB lists and updated non-indigenous concept, a careful literature review was carried out, reporting data on 33 NIB from 14 Mediterranean countries (Algeria, Croatia, Cyprus, Egypt, France, Greece, Israel, Italy, Lebanon, Malta, Spain, Syria, Tunisia and Turkey). A total of 296 valid records were listed, including 6 yet unpublished. Other 62 records were labelled as uncertain and listed separately, until further analyses on taxonomic identity, non-indigenous status and distribution patterns of the species involved will clarify their status. The countries with the higher numbers of NIB and single records are Lebanon (20 and 78, respectively) and Italy (12 and 112, respectively). The distribution of NIB in the Mediterranean Sea appears scattered and no data are available at all for eight countries. Studies and monitoring efforts on bryozoans in the Mediterranean Sea are not evenly distributed, probably as a consequence of the decrease in number of expert taxonomists and the poor allocation of funds on biodiversity studies. The coordination among Mediterranean countries on standardised sampling methods is needed in order to create a comprehensive baseline knowledge on NIB distribution in the Mediterranean Sea and prioritise taxa and countries that are still poorly investigated.

Correction: A massive update of non-indigenous species records in Mediterranean marinas

[This corrects the article DOI: 10.7717/peerj.3954.].