Research Center; Marraffini et al., 2017); ii) vertical fouling panels of the same
structure; iii) underwater scrapes of quadrat frames from vertical substrata. All methods
involved a standard surface of 14x14 cm. Both horizontal and vertical panels were
deployed at the end of April and retrieved in July, concurrently with the scrapes. The
biogeographical status of the species identified in the lab was carefully analysed to
distinguish NIS from native species (including cryptogenic species). Multivariate
statistics were based on presence/absence data.
Results
A total of 58 sessile taxa were identified, including 9 NIS. In particular, 40 species were
identified from the horizontal panels (including all 9 NIS), 34 from vertical panels (7
NIS) and 29 from scrape samples (5 NIS). A significant difference among sampling
methods was observed through a one-way PERMANOVA test (Pseudo-F= 5.0259;
P(perm)= 0.0001; Unique perms= 9919), and the pairwise test confirmed a significant
difference between pairs of methods (P(perm)<0.05).
Discussion and Conclusions
The comparison of three selected sampling methods to collect fouling communities
revealed a better performance of the SERC method in detecting NIS, as well as the
native sessile species. This result reflects the observations of a previous study carried
out in USA, even if in our experiment it was not possible to collect samples under the
floating pontoons (i.e., scraping horizontal surfaces), for the impossibility of obtaining
authorizations (Marraffini et al., 2017). The downward horizontal position of the PVC
panels strongly limits the growth of algae, favouring the settlement of fouling
macrofauna. Yet, scrape samples collected in snorkelling had additional taxa not
observed on the panels. Other similar tests would be recommended in other localities to
confirm the preliminary results of this study.
Bibliography
GALIL B.S., MARCHINI A., OCCHIPINTI-AMBROGI A. (2018) - East is east and West is
west? Management of marine bioinvasions in the Mediterranean Sea. Estuarine, Coastal and
Shelf Science, 201, 5: 7-16.
MARRAFFINI M.L., ASHTON G.V., BROWN C.W., CHANG A.L., RUIZ G.M. (2017).
Settlement plates as monitoring devices for non-indigenous species in marine fouling
communities. Management of Biological Invasions, 8(4): 559-566.
SEEBENS H., GASTNER M.T., BLASIUS B., COURCHAMP F. (2013) - The risk of marine
bioinvasion caused by global shipping. Ecology Letters, 16(6): 782-790.
ULMAN A., FERRARIO J., FORCADA A., SEEBENS H., ARVANITIDIS C., OCCHIPINTI‐
AMBROGI A., MARCHINI A. (2019) - Alien species spreading via biofouling on
recreational vessels in the Mediterranean Sea. J. Appl. Ecol., 56 (12): 2620-2629.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
94
structure; iii) underwater scrapes of quadrat frames from vertical substrata. All methods
involved a standard surface of 14x14 cm. Both horizontal and vertical panels were
deployed at the end of April and retrieved in July, concurrently with the scrapes. The
biogeographical status of the species identified in the lab was carefully analysed to
distinguish NIS from native species (including cryptogenic species). Multivariate
statistics were based on presence/absence data.
Results
A total of 58 sessile taxa were identified, including 9 NIS. In particular, 40 species were
identified from the horizontal panels (including all 9 NIS), 34 from vertical panels (7
NIS) and 29 from scrape samples (5 NIS). A significant difference among sampling
methods was observed through a one-way PERMANOVA test (Pseudo-F= 5.0259;
P(perm)= 0.0001; Unique perms= 9919), and the pairwise test confirmed a significant
difference between pairs of methods (P(perm)<0.05).
Discussion and Conclusions
The comparison of three selected sampling methods to collect fouling communities
revealed a better performance of the SERC method in detecting NIS, as well as the
native sessile species. This result reflects the observations of a previous study carried
out in USA, even if in our experiment it was not possible to collect samples under the
floating pontoons (i.e., scraping horizontal surfaces), for the impossibility of obtaining
authorizations (Marraffini et al., 2017). The downward horizontal position of the PVC
panels strongly limits the growth of algae, favouring the settlement of fouling
macrofauna. Yet, scrape samples collected in snorkelling had additional taxa not
observed on the panels. Other similar tests would be recommended in other localities to
confirm the preliminary results of this study.
Bibliography
GALIL B.S., MARCHINI A., OCCHIPINTI-AMBROGI A. (2018) - East is east and West is
west? Management of marine bioinvasions in the Mediterranean Sea. Estuarine, Coastal and
Shelf Science, 201, 5: 7-16.
MARRAFFINI M.L., ASHTON G.V., BROWN C.W., CHANG A.L., RUIZ G.M. (2017).
Settlement plates as monitoring devices for non-indigenous species in marine fouling
communities. Management of Biological Invasions, 8(4): 559-566.
SEEBENS H., GASTNER M.T., BLASIUS B., COURCHAMP F. (2013) - The risk of marine
bioinvasion caused by global shipping. Ecology Letters, 16(6): 782-790.
ULMAN A., FERRARIO J., FORCADA A., SEEBENS H., ARVANITIDIS C., OCCHIPINTI‐
AMBROGI A., MARCHINI A. (2019) - Alien species spreading via biofouling on
recreational vessels in the Mediterranean Sea. J. Appl. Ecol., 56 (12): 2620-2629.
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
94