Fig.1: Percentage of species per taxonomic group in the three investigated sites.
Discussion and conclusions
This study allowed us to assess the fouling communities in three marinas within the
coastal stretch of San Remo, a site not yet investigated for NIS presence. A total of 11
NIS was identified, but no new Mediterranean or country records were reported; all the
NIS observed were already known from the Ligurian Sea (Ferrario et al., 2017;
Tamburini et al., 2020). All the investigated sites were significantly different to each
other, despite a low average dissimilarity was observed between the two active marinas
(Porto Sole and Porto Vecchio). Apart from the higher number of species recorded in
Ospedaletti in comparison to the other localities, the fouling community of the unused
marina showed a higher abundance of species more common in natural habitats instead
of ports, and with only two NIS. These results suggest that the presence of boats can
strongly influence the structure of fouling communities, and that a higher propagule
pressure can facilitate the establishment of NIS (Occhipinti-Ambrogi, 2007). It would
be interesting to monitor the site of Ospedaletti once active, in order to verify if
recreational boating will actually lead to an increase in the number of NIS.
Furthermore, the sites of Porto Vecchio and Porto Sole displayed similar fouling
assemblages with comparable numbers of native and non-indigenous species. A
different effect of the maritime traffic (fishing VS recreational boats) was not observed,
but this could be also related to the proximity of the two sites, which inevitably
influence each other. Further investigation should be carried out to test ports with
different maritime traffic, including biotic and abiotic factors proper of each site, in
order to identify the features of the ports most at risk of invasion.
Acknowledgments
The authors are grateful to the Municipality of San Remo for granting the permission to
sampling and to Lorenzo Goppa for the logistic support during the sampling.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
40
Discussion and conclusions
This study allowed us to assess the fouling communities in three marinas within the
coastal stretch of San Remo, a site not yet investigated for NIS presence. A total of 11
NIS was identified, but no new Mediterranean or country records were reported; all the
NIS observed were already known from the Ligurian Sea (Ferrario et al., 2017;
Tamburini et al., 2020). All the investigated sites were significantly different to each
other, despite a low average dissimilarity was observed between the two active marinas
(Porto Sole and Porto Vecchio). Apart from the higher number of species recorded in
Ospedaletti in comparison to the other localities, the fouling community of the unused
marina showed a higher abundance of species more common in natural habitats instead
of ports, and with only two NIS. These results suggest that the presence of boats can
strongly influence the structure of fouling communities, and that a higher propagule
pressure can facilitate the establishment of NIS (Occhipinti-Ambrogi, 2007). It would
be interesting to monitor the site of Ospedaletti once active, in order to verify if
recreational boating will actually lead to an increase in the number of NIS.
Furthermore, the sites of Porto Vecchio and Porto Sole displayed similar fouling
assemblages with comparable numbers of native and non-indigenous species. A
different effect of the maritime traffic (fishing VS recreational boats) was not observed,
but this could be also related to the proximity of the two sites, which inevitably
influence each other. Further investigation should be carried out to test ports with
different maritime traffic, including biotic and abiotic factors proper of each site, in
order to identify the features of the ports most at risk of invasion.
Acknowledgments
The authors are grateful to the Municipality of San Remo for granting the permission to
sampling and to Lorenzo Goppa for the logistic support during the sampling.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
40