Abstract
Baseline port monitoring for fouling communities is an essential tool to assess non-indigenous species (NIS) introduction and spread, but a standardized and coordinated method among Mediterranean and European countries has not yet been adopted. In this context, it is important to test monitoring protocols that allow for the collection of standardized and directly comparable data, replicated across time and space. Here, for the first time in the Mediterranean Sea, we tested a standardized protocol developed by the Smithsonian Environmental Research Center (SERC) and used now in several countries. The 3-year monitoring survey (2018–2020) was conducted in the Gulf of La Spezia (Ligurian Sea, Italy), with the deployment of a total of 50 PVC panels per year in five different sites (a commercial harbor, three marinas and a site in the proximity of a shellfish farm). A total of 79 taxa were identified, including 11 NIS, ranging from zero to seven NIS for each panel. In comparison with previous surveys, new NIS arrivals were observed in the Gulf of La Spezia: Botrylloides cf. niger, Branchiomma sp., Branchiomma luctuosum, Paraleucilla magna, and Watersipora arcuata. At the end of the 3-year monitoring, mean richness? and percent cover of NIS were measured, and both measures differed across the monitoring sites, with higher values in two marinas and in the commercial harbor. Among years, richness of NIS was relatively stable at each monitoring site. The structure of the fouling was influenced more by native and cryptogenic species than by NIS. Moreover, among the monitoring sites, the density of artificial structures was not a reliable predictor or proxy for local NIS abundance. This first application of the SERC method in the Mediterranean Sea, demonstrates both pros and cons, including the detection of new NIS reported here. Further direct comparisons with other NIS monitoring tools are recommended, and additional tests to assess its effectiveness in this biogeographical area are encouraged. A broader application of this and other standard methods across temporal and spatial scales in the Mediterranean basin should be implemented, providing critical data needed to assess changes in the structure of fouling communities.
Introduction
The introduction of non-indigenous species (NIS) in marine environments is considered one of the most important factors contributing to global change (Ruiz et al., 1997; Occhipinti-Ambrogi, 2007; ), including both ecological and economic impacts (Occhipinti-Ambrogi, 2007; ; Ojaveer et al., 2015). The Mediterranean Sea is among the most invaded marine provinces (), with almost 800 multicellular NIS recorded (), and the main vectors of introduction include: the opening and enlargement of the Suez Canal, aquaculture and shipping (Ruiz et al., 2000; , ; ; Tsiamis et al., 2020). While most species introduced through the Suez Canal and by aquaculture vectors are generally confined in relatively restricted areas, vessels can further spread NIS throughout the whole Mediterranean Basin (). The maritime traffic involved in the introduction and spread of NIS includes both large commercial and small recreational vessels, which can carry species inside the ballast waters or as biofouling on vessel hulls (Ruiz et al., 2000; ; ; Zabin, 2014; ; ). As defined by the International Maritime Organization, biofouling is “the accumulation of aquatic organisms such as microorganisms, plants and animals, on surfaces and structures immersed in or exposed to the aquatic environment” (). The macrozoobenthic component of the fouling communities is usually composed of both sessile epibionts—sponges, serpulids, bivalves, barnacles, bryozoans, tunicates—and mobile marine invertebrates, like but not limited to flatworms, amphipods, isopods, sea spiders and brittle stars (; ; ; ; ; ).
Maritime traffic plays a key role in the introduction of fouling NIS, favoring their first settlement and establishment in ports and then creating hotspot areas for NIS. It has long been considered that large commercial ports act as primary hubs for fouling NIS, due to the transit of transoceanic cargo ships, while small boats are involved in their secondary spread in marinas and neighboring areas (Minchin et al., 2006; ; ; Ros et al., 2013; Zabin, 2014; Marchini et al., 2015). On the other hand, recent studies have suggested the importance of recreational boating in the primary introduction and spread of NIS (; ; Ulman et al., 2019a,b). After introduction to a port environment, the settlement of NIS can be facilitated both by the large abundance of available artificial substrates () and the tolerance of these species to different environmental conditions, including polluted waters (Piola and Johnston, 2008; Piola et al., 2009).
For decades, fouling assemblages have served as a model to study bioinvasion processes (Ruiz et al., 2009; ; Marraffini et al., 2017; ; ; Vieira et al., 2018; ). Furthermore, ports and marinas can be considered ideal sites for the early detection and monitoring of NIS presence and abundance, due to their importance as hotspot areas of NIS (Olenin et al., 2011; Ojaveer et al., 2014; Marraffini et al., 2017). However, no formal protocol has yet been adopted for the standardized assessment of fouling NIS in the European and Mediterranean marine regions. Monitoring of marine fouling communities is fundamental to track the introduction and spread of NIS, as well as to evaluate the power of legislation designed for limiting further introductions (Ruiz and Hewitt, 2002; ; Marraffini et al., 2017). The implementation of long-term monitoring programs and a preventive approach can contribute to the assessment of the potential risks of NIS that have been demonstrated to negatively affect native communities—e.g., contributing to the decrease of vulnerable species (Marraffini et al., 2017; Occhipinti-Ambrogi, 2021). For these reasons, a standardized monitoring and a coordination among countries is highly recommended, in order to obtain comparable data replicated across time and space (; Olenin et al., 2010, 2011; ; ). This is also in accordance with the Marine Strategy Framework Directive (MSFD 2008/56/EC), suggesting a development and application of standardized methods to detect NIS—a descriptor included in the achievement of the Good Environmental Status in European marine waters.
Several methodologies for sampling fouling communities in port habitats have been developed over the years. Most common techniques include (i) Rapid Assessment Surveys—RAS (e.g., ; ; Olenin et al., 2007; Minchin, 2012; ; Marchini et al., 2015; ; Ulman et al., 2017); (ii) net-assisted scraping (e.g., ; Ulman et al., 2017; Tempesti et al., 2020), including quadrat scraping during snorkeling or scuba diving (e.g., Neves et al., 2007; ; Ulman et al., 2019b); and artificial substrate units (ASU), such as (iii) two-dimensional settlement panels (e.g., Relini, 1977; ; ; ; ; ; ; ); and (iv) three-dimensional artificial habitat collectors (e.g., ; ; Outinen et al., 2019; ; Obst et al., 2020; Ros et al., 2020). Any of the above methods involves both advantages and disadvantages, and their success or suitability depend on the aim of the study. For example, quantitative methods (e.g., quadrats, settlement panels) are useful to thoroughly assess the entire fouling community but require a lot of fieldwork and laboratory effort. Conversely, qualitative methods like RAS allow for the collection of a lot of data on species distribution in a short timeframe, but the focus is typically only on target NIS already known and easily recognizable in the field. This method can limit the early detection of new arrivals, particularly of inconspicuous NIS. Net-assisted scraping probably ensures the most comprehensive picture of the fouling community, yet it requires long laboratory analyses and does not provide quantitative outputs (although semi-quantitative abundance estimates are possible; ). In addition, some methods are more suitable for sessile taxa (e.g., settlement panels), while other ones are better for mobile taxa (e.g., scrapes, 3-D ASU). Light exposure and orientation of the ASU also affects the ability of collecting the photosynthetic component of fouling communities. Therefore, the best practice for comprehensive sampling fouling communities should be a simultaneous multi-method approach in the same study area, as suggested by Tait et al. (2018) and .
In recent years, several sampling efforts focused along European and Mediterranean ports were conducted to monitor NIS presence. Using RAS, and Nall et al. (2015) sampled in Scotland, while sampled with the same method in the English Channel. In the Normandy region, Verlaque and Breton (2019) found macroalgal NIS through a RAS by scuba diving, involving citizen scientists after a multi-year field survey. In the ports of Gdynia and Gdańsk (Baltic Sea), found a non-indigenous tanaid species using both settlement panels and artificial habitat collectors. In the subtropical island of Madeira (Atlantic Ocean), monitored NIS presence and abundance with a 6-year fouling survey through settlement panels. Regarding the Mediterranean Sea, sampled ports in the Western sector (Sardinian Sea, Ligurian Sea, and North Tyrrhenian Sea) by scraping the artificial hard substrates with a rigid hand-held net and Tempesti et al. (2020) sampled in the same way in the port area of Leghorn. In the Taranto Sea (Ionian Sea), carried out a 2-year macrofouling monitoring program using PVC settlement panels, while along the Slovenian coasts combined different methods (RAS, scraping net and scuba dives) in their monitoring. In the Aegean Sea, reported for the first time a non-indigenous nudibranch, using Autonomous Reef Monitoring Structures (ARMS) protocol, proposed by Obst et al. (2020). In the Southern Mediterranean Sea, sampled through RAS fishing ports and marinas in Monastir Bay, Tunisia. Lastly, the broadest investigation of non-indigenous invertebrates in Mediterranean marinas was conducted by Ulman et al. (2017) with both modified RAS and scrapes by hand-held rigid net. During the last few years, the metabarcoding approach has also started to be employed in NIS surveys with satisfying results (see also ; Miralles et al., 2021; Pearman et al., 2021). Metabarcoding can be considered as an efficient tool to detect cryptic species or early life stages, but one of the main disadvantages is the incompleteness of genetic sequence reference libraries (Zaiko et al., 2018; ). For this reason, an integrative approach should be considered as the gold standard (Padial et al., 2010; ; Obst et al., 2020; ).
In this study we applied for the first time in the Mediterranean Sea—namely in the Gulf of La Spezia (Ligurian Sea. Italy)—an international standard protocol for sessile fouling NIS monitoring in port habitats, with the aim to assess: (i) the fouling communities and NIS colonization in different harbor sites; (ii) the development of NIS colonization in the fouling communities over time; (iii) the effectiveness of this protocol for the early detection of newly introduced NIS in the Mediterranean; and (iv) the relationship between abundance of NIS and density of artificial structures in port habitats.
Materials and Methods
Study Area
The Gulf of La Spezia (44.09°N, 9.85°E) is one of the largest bays of the Ligurian Sea (Italy), characterized by the presence of several anthropogenic activities, including a commercial harbor and several marinas, and featuring intense anthropogenic influences such as urban runoff, naval industries, a military base, an electric power-plant and aquaculture facilities (). The bay is about 5 km wide and 10 km long, and is separated in two parts by an artificial offshore dam about 2 km long ().
The fouling monitoring program included five sites inside the gulf (Figure 1): in the marinas of Fezzano, Le Grazie and Porto Venere (FE, GR, and PV, respectively), near the commercial harbor of La Spezia (SP), and in a small marina near a mussel culture facility in Santa Teresa (ST). The trend of sea surface temperature (−0.915 m) from August 2018 to August 2020 was obtained by extrapolating data from loggers (ONSET HOBO WaterTemp Pro v2) deployed in the gulf for other experimental purposes by ENEA Marine Environment Research Centre (La Spezia).
FIGURE 1
Monitoring Protocol
The monitoring was carried out for three consecutive years (2018–2020) by applying a standardized protocol developed by the Smithsonian Environmental Research Center (Edgewater, MD, United States) that is being used to detect and track NIS in the U.S as well as Canada, Ecuador, and Panama (see also
The percent cover of the whole fouling assemblage was assessed by point count method (n = 50 points;
Data Analysis
Species richness (S), NIS/native ratio and percent cover of each taxon were calculated for each panel (N = 10 per site). S and percent cover were assessed separately for all taxa, together with the assignment of biogeographic status sensu
Percent cover data were analyzed using principal coordinate analysis (PCO) in order to visualize the pattern of clustering among fouling communities from each site during the years of monitoring. The ordination technique was carried out on centroids (year × site), based on Bray-Curtis similarity on fourth root transformed taxa percent cover data. PCO both for the whole community, and for NIS and native species component were applied separately. Distance-based test for homogeneity of multivariate dispersions (PERMDISP) and permutational multivariate analysis of variance (PERMANOVA) were carried out to test differences in NIS percent cover values of communities among sites (
Correlation between NIS percent cover and density of immersed artificial structures (e.g., docks, pontoons) of each monitoring site was tested, as suggested by Susick et al. (2020). Density of each site was measured through satellite images as the linear length of mooring structures within a 200 m diameter circle of the potential marine habitat, centered on the spatial centroid of deployed panels. Length of artificial structure visible above water was measured using the path ruler tool in Google Earth Pro v. 7.3.3.7699 (Susick et al., 2020).
Analyses were carried out with the software Microsoft Excel, R (R Core Team., 2017), QGIS (QGIS Development Team., 2020) and PRIMER 6 with PERMANOVA + add-on package (
Results
From August 2018 to August 2020, the range of surface temperature varied from 12 to 27°C (Supplementary Figure 1). Mean temperatures during the monitoring periods were 25 ± 1°C in 2018, 19 ± 3°C in 2019 and 21 ± 2°C in 2020.
Overall, we collected 126 out of the 150 panels initially deployed in the 3 years; the remaining panels (nine in 2018, four in 2019, and 11 in 2020) were lost due to external causes (e.g., coastal storms or vandalism).
After the 3-year monitoring, a total of 79 sessile taxa representing seven phyla were documented from the Gulf of La Spezia (Figure 2), including 11 NIS: four Bryozoa, four Annelida, one Porifera, and two Tunicata (Table 1). Among all the NIS observed, one has not been identified at species level (i.e., Branchiomma sp.). This species has been firstly assigned to Branchiomma boholense (Grube, 1878), but an accurate analysis of the specimens revealed divergent taxonomic characters, that cannot be attributed to the other Branchiomma spp. known to occur in the Mediterranean Sea, including the non-indigenous Branchiomma bairdi (McIntosh, 1885), B. boholense and Branchiomma luctuosum (
FIGURE 2

Number of taxa found in the Gulf of La Spezia grouped by large taxonomic groups.
TABLE 1

List of the NIS found in the investigated localities.
Asterisk indicates NIS found for the first time in the Gulf of La Spezia.
For species richness, the lowest value of mean S at each site, i.e., Stot (± SD), was observed in SP in 2018 (11 ± 4), while the highest in ST in the same year (22 ± 2) (Figure 3). Regarding the mean SNIS, the lowest value was recorded in PV in 2019 (1 ± 1) and the highest in FE, GR and ST in 2018, as well as in FE and GR in 2020 (about five species on average). S of native and cryptogenic species (Snative) was the lowest in SP 2018 (7 ± 3) and the highest in PV 2020 (18 ± 3) (Figure 3). The mean NIS/(native + cryptogenic species) ratio showed a similar pattern, registering the lowest values in PV 2019 and 2020 (0.1 ± 0.04) and the highest in SP 2018 (0.6 ± 0.2). Snative resulted significantly different among sites, but not across years (F = 11.3172, p = 9.73 × 10–8; F = 1.6857, p = 0.19003, respectively). The site × year interaction resulted significant (F = 3.9884, p = 3.462 × 10–4) and post hoc test revealed that a single site (SP) contributed to this interaction (2018 vs. 2019 adjusted p = 2.913 × 10–4; 2018 vs. 2020 adjusted p = 7.745 × 10–4). Similarly, SNIS showed significative differences only among sites (F = 5.5382, p = 4.21 × 10–4) and not across years (F = 1.7775, p = 0.1738433), and no interaction was detected (F = 0.988, p = 0.4493411). Among the sites, PV showed significant differences with all the other four sites (adjusted p < 0.001).
FIGURE 3

Mean species richness (S) of each monitoring site during the years of monitoring. Sites are showed at decreasing distance from La Spezia (SP). Abbreviations of sites are indicated in Figure 1.
Merging the data of the 3 years of monitoring, the sites with the highest and the lowest values of mean Stot were ST (21 ± 3) and SP (16 ± 5), respectively; while considering SNIS, the highest value was found in FE (5 ± 1) and the lowest in PV (2 ± 1). Most of the sites displayed higher values of mean Snative, namely GR (15 ± 4), PV (15 ± 4), and ST (15 ± 3); conversely, SP (11 ± 4) showed a slightly lower value (Table 2). During the 3 years of monitoring, mean percent cover of NIS was the lowest in PV (17 ± 23%) and the highest in SP (85 ± 50%).
TABLE 2
| Site | S (total species) | S (NIS) | S (native + cryptogenic species) |
| FE | 17.5 ± 4.4 | 4.7 ± 1.2 | 12.1 ± 3.7 |
| GR | 19.8 ± 4.9 | 4.2 ± 1.3 | 14.9 ± 4.1 |
| PV | 18.3 ± 4.4 | 2.0 ± 1.2 | 15.2 ± 4.0 |
| SP | 15.7 ± 4.7 | 3.8 ± 1.2 | 11.1 ± 4.2 |
| ST | 20.6 ± 3.0 | 4.2 ± 1.3 | 15.4 ± 2.9 |
Mean values of S (± SD) per site for the entire 3-year period of monitoring.
S (total species, including unresolved taxa), mean number per plate of taxa in each site; S (NIS), mean number per plate of NIS in each site; S (native + cryptogenic species), mean number per plate of native and cryptogenic species in each site.
Abbreviations of sites are explained in Figure 1.
Mean percent cover of native and cryptogenic species (Figure 4A) was highest value in GR 2020 (141 ± 32%) and lowest in SP 2018 (42 ± 35%). For NIS, mean percent cover (Figure 4B) was highest in SP 2018 (118 ± 38%) and lowest in PV 2019 (4 ± 5%). Percent cover of native species was significantly different across years (F = 9.0727, p = 2.241 × 10–4) and sites (F = 3.1586, p = 0.0168232), with no significant interaction (F = 1.5418, p = 0.1508879). Across years, the values observed in 2020 showed significant differences with 2018 and 2019 (adjusted p < 0.001); among sites, PV resulted significantly different from FE and SP (adjusted p < 0.01) (Figure 4A). Significant main effects were detected for NIS cover among sites (F = 7.5473, p = 2.05 × 10–05) and across years (F = 14.5618, p = 2.42E-06), but no interaction effect was detected (F = 1.2237, p = 0.2918). Post hoc tests revealed that percent cover of NIS was different between 2018 and the other 2 years (p < 0.001); between PV and the other four sites (p < 0.01); between ST and the other sites (p < 0.01) (Figure 4B).
FIGURE 4

Mean (+ SD) percent cover of native and cryptogenic species (A), and NIS (B) in each monitoring site during the 3 years of monitoring. Letters (a, b) on the top of the two graphs indicate statistical divergence among years, while symbols on the bottom indicate statistical divergence among sites. Sites are showed at decreasing distance from La Spezia (SP) and abbreviations of sites are indicated in Figure 1.
The investigated sites were significantly different in terms of mean richness and percent cover of NIS, considering the 3 years of monitoring (F = 14.691, p = 8.257 × 10–10; F = 13.494, p = 4.00 × 10–9, respectively). Tukey’s tests showed a significant difference in richness between PV and all the other sites (p < 0.001) when considering SNIS. On the basis of NIS cover a significant difference came out between the sites PV-FE, PV-GR, and PV-SP (p < 0.001); ST-FE (p < 0.05) and ST-SP (p < 0.001). Relative abundance—i.e., percent cover data standardized to 100%—of unresolved taxa resulted very low in all sites (1–2%); while values for NIS and native species were similar in FE and SP (about 50% each); and in GR, PV, and ST the relative abundances were higher for the native species (63, 85, and 71%, respectively) in comparison with the NIS (36, 13, and 28%, respectively; Figure 5).
FIGURE 5

Relative abundance (%) of NIS percent cover (black bar), percent cover of native and cryptogenic species (white bar) and unresolved taxa percent cover (gray bar) in the monitoring sites in the 3-year monitoring. Sites are showed at decreasing distance from La Spezia (SP). Abbreviations of sites are indicated in Figure 1.
Regarding the structure of fouling communities, PCO showed slightly separated clusters per sampling year and the same distribution of sites within each year, with SP and PV being the most diversified sites (Figure 6). This pattern probably follows the percent cover of native species rather than NIS, which did not show a clear arrangement (Supplementary Figure 2). Furthermore, the values on percent cover of the non-indigenous component were more clumped than the native one (Supplementary Figure 2). PERMANOVA main test on NIS percent cover data of communities among monitoring sites (years merged) showed significant dissimilarity among community composition [pseudo-F = 13.138, p(perm) = 0.0001, unique permutations: 9915], while PERMDISP highlighted significant deviations of samples from centroid [F = 3.7702, p(perm) = 0.0116], rejecting the hypothesis of no difference in dispersion among the groups, i.e., “non-homogeneity” of samples dispersion. Moreover, pairwise PERMANOVA tests showed significant differences among sites, except for FE and GR [t = 1.3337, p(perm) = 0.1371, unique permutations: 9956], which therefore showed not-dissimilar NIS communities.
FIGURE 6

PCO (Principal Coordinate Analysis) based on distance among centroids (year × site) of whole fouling community percent cover data. Abbreviations of sites are indicated in Figure 1.
Density of artificial structures was the highest in SP (36.28 km × km–2) and the lowest in PV (13.74 km × km–2), with intermediate values in GR (29.04 km × km–2), FE (22.91 km × km–2), and ST (14.51 km × km–2). Correlation between NIS percent cover of samples (126) and these calculated densities resulted low (adjusted R2 = 0.2144, p = 2.876 × 10–8; Supplementary Figure 3).
Discussion
The 3-year monitoring on fouling communities in the Gulf of La Spezia allowed us to collect 79 taxa, half of which belong to Bryozoa and Tunicata, and to detect a total of 11 NIS. Seven NIS were already reported in the Gulf in 2010–2013 (
For the NIS observed in the present study, Paraleucilla magna is the only sponge reported as non-indigenous in the Mediterranean Sea (
Regarding Branchiomma sp., we think this taxon must be further investigated, as this genus showed intraspecific variability that can lead to species misidentification (
Branchiomma luctuosum, originally described from the Red Sea (
The bryozoan Watersipora arcuata was reported for the first time in the Mediterranean Sea in 2013 in the Ligurian Sea (
Finally, Botrylloides niger, a colonial ascidian native from the tropical Western Atlantic, is reported in several tropical and warm water regions across the world (Sheets et al., 2016), including Madeira island (Ramalhosa et al., 2021). In the Mediterranean Sea, it was first found in 2006 in Israel (Rubinstein et al., 2013) and erroneously identified as Botrylloides leachii (Savigny, 1816;
Our monitoring showed that mean NIS richness away varied from 1 to 5 species among sites and years, with similar values across the years of monitoring. For this reason, we did not find a clear increasing pattern in new NIS detections in the different sites, but continuation of this monitoring is required to identify more robust temporal patterns. On the other hand, native species richness significantly varied only in La Spezia among years, highlighting a stable number of native species during the monitoring. It should be highlighted that B. cf. niger was recorded only in 2018 in ST, but in the following years it did not disappear from the marina. Despite not being found on panel communities, it was still observed, even if in very low abundances, on other artificial substrates (e.g., on the supporting structure of the panels and on floating pontoons; authors personal observation). For this reason, B. cf. niger may be considered as an established NIS in the study area. After 3 years of monitoring, Porto Venere was found to be the least impacted site in terms of both richness and percent cover of NIS, while the other sites showed a higher impact by NIS, with values of mean NIS percent cover ranging from 34% (Santa Teresa) to 85% (La Spezia).
In general, the different submersion periods—mid-summer in 2018 and early spring in the following years—affected the development of fouling assemblages, mainly in terms of differences in taxa percent cover. NIS richness were indeed similar across the years of monitoring, while in 2018 definitely higher mean values of NIS cover were observed in all sites, compared to the other years of monitoring. The latter result is probably a consequence of the later submersion period of 2018, which led to the dominance on the panels of one NIS, namely Hydroides elegans (Haswell, 1883). A similar phenomenon with the dominance of one single species in fouling communities was also observed in marinas of South-eastern Brazil (
Considering the whole data set on NIS percent cover of the 3-year monitoring, higher values were found in La Spezia, with Fezzano, Le Grazie, Santa Teresa, and Porto Venere gradually showing lower values. The same gradient from La Spezia to Porto Venere was also observed when considering the structure of the entire community, and the gradient was probably more influenced by the composition of the native species than to the non-indigenous one. These patterns may reflect the different geographic features of the monitoring sites. In fact, the sites are located at an increasing distance from the main harbor of La Spezia, one of the largest commercial ports in Italy (accessed 1 March 2021)1. The harbor of La Spezia hosts international cargo ships and passengers’ vessels, as well as local ferries.
The distance of sites from the main harbor appears to be proportional to the mean NIS percent cover, while the proximity of Santa Teresa to the mussel farm showed higher abundances of P. magna, a NIS associated to aquaculture (
In conclusion, this monitoring allowed us to implement, for the first time in the Mediterranean Sea, an international standard protocol developed by the SERC to assess fouling communities and detect NIS. The number of detected NIS was in line with previous monitoring carried out in the Gulf of La Spezia and in other Ligurian port localities, but with additional new records for the area and three NIS no longer observed (
While this methodology provides a reliable option for sampling and monitoring fouling communities in the Mediterranean area, further analyses to test its effectiveness should be encouraged in other regional localities, together with a comparison to other fouling monitoring tools, including the use of genetic approaches (e.g.,
Statements
Data availability statement
The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author/s.
Author contributions
JF, EK, GMR, and AO-A conceived the study. MT, JF, EK, AM, and MFR performed the field work and laboratory analyses. MT carried out the statistics and wrote the first draft of the manuscript, with the contribution of JF. AO-A and GMR acquired funds. All the authors contributed to the manuscript revision, read and approved the submitted version.
Funding
Financial support to this project comes from MT Ph.D. scholarship (XXXIV Cycle), granted by the Department of Earth and Environmental Sciences of Pavia University, and by the crowdfunding project “A brick against alien species,” promoted by the “Universitiamo by UNIPV” platform at: https://universitiamo.eu/en/campaigns/un-mattone-contro-le-specie-aliene/. The authors declare that this study received funding from Boldarino S.P.A. and Curtiriso S.R.L., the main sponsors of the fundraising project “A brick against alien species”. These funders were not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication.
Acknowledgments
We are grateful to: Municipality of Porto Venere, Port Authority of the Eastern Ligurian Sea, Scuola di Mare Santa Teresa, Cantiere Valdettaro, and Assonautica La Spezia for granting permissions for this study; Chiara Lombardi, Matteo Nannini and Andrea Bordone (ENEA La Spezia) for the logistic support and the temperature dataset; all the collaborators and students involved in logistic support during sampling surveys and laboratory activities (Alessandro Migliavacca, Alessandro Piazza, Alice Grioni, Chiara Mondaini, Cristina Cremonesi, Elisa Bigarella, Federica Gola, Gianmarco Riva, Giulia Quaini, Laura Francia, Lorenzo Pizzamiglio, and Marcella Lo Vullo) Alfonso Ángel Ramos Esplà (University of Alicante) and Joachim Langeneck (University of Pisa) for confirming the taxonomic identification of some ascidian and polychaete species, respectively, Ilaria Cabrini and the fundraising team “Universitiamo by UniPv”; Boldarino S.P.A and Curtiriso S.R.L and all the other donors and sponsors of the project; and Andrea Taccani (University of Pavia) for invaluable support in communication actions.
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Supplementary material
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmars.2021.700730/full#supplementary-material
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Summary
Keywords
macrozoobenthos, sessile fauna, settlement panels, marine bioinvasions, Ligurian Sea, fouling
Citation
Tamburini M, Keppel E, Marchini A, Repetto MF, Ruiz GM, Ferrario J and Occhipinti-Ambrogi A (2021) Monitoring Non-indigenous Species in Port Habitats: First Application of a Standardized North American Protocol in the Mediterranean Sea. Front. Mar. Sci. 8:700730. doi: 10.3389/fmars.2021.700730
Received
26 April 2021
Accepted
21 June 2021
Published
16 July 2021
Volume
8 - 2021
Edited by
Periklis Kleitou, Marine and Environmental Research Lab (MER), Cyprus
Reviewed by
Thanos Dailianis, Hellenic Centre for Marine Research (HCMR), Greece; Vasilis Gerovasileiou, Hellenic Centre for Marine Research (HCMR), Greece
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Copyright
© 2021 Tamburini, Keppel, Marchini, Repetto, Ruiz, Ferrario and Occhipinti-Ambrogi.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Jasmine Ferrario, jasmine.ferrario@unipv.it
†These authors have contributed equally to this work and share senior authorship
This article was submitted to Marine Biology, a section of the journal Frontiers in Marine Science
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