Mar SANTOS-SIMÓN, FERRARIO J., BENADUCE-ORTIZ B., ORTIZZARRAGOITIA M., MARCHINI A.
Zoology & Animal Cell Biology Department, University of the Basque Country, PO Box
644, 48080 Bilbao, Basque Country, Spain
E-mail: mar.santos@ehu.eus
TESTING EFFECTIVENESS OF DIFFERENT ANTIFOULING AND BOAT
MAINTENANCE PRACTICES IN THE CONTEXT OF BIOINVASIONS
Abstract
Biofouling, known as the settlement and growth of organisms on wetted surfaces, is one of the major
challenges faced by the boating sector, since it can compromise the hydrodynamics and efficiency of
boats, while contributing to the spread of non-indigenous species (NIS). In this context, different
antifouling solutions have been developed, being the most common ones biocide-based. Although
highly effective, some of these compounds have proven to have adverse effects on the environment.
Thus, new commercially available alternatives have been developed, including non-toxic solutions
focused on altering the surface characteristics of the ship hull. This research aims to test in field
conditions the effectiveness of different antifouling solutions, including paint type (biocide-based; nontoxic; no paint) and maintenance practices (regular hull cleaning; no cleaning). For this purpose, 48
PVC panels with different treatments were submerged in two marinas located in the Gulf of La Spezia
(Italy) and sampled at two different periods. Panels were analysed in the lab to determine how
community structure and composition differed according to the treatment and time, giving special
attention to NIS and initial colonizers. Preliminary results show a significant difference according to
treatment, both at community level and total biomass. Besides, Watersipora subtorquata has been
identified as a biocide resistant organism that facilitates the attachment of others. Further analysis of
the samples will enable to: 1) determine the extent of effects of each of the factors, 2) assess differences
in NIS presence and abundance among factors and 3) suggest best practices for boat maintenance
and point out priorities for biofouling management.
Key-words: biofouling, antifouling paints, bioinvasions, non-indigenous species, recreational boats
Introduction
Fouling communities of recreational boats have proven to be one of the major vectors of
introduction and dispersion of non-indigenous species (NIS) (Ulman et al., 2019). To avoid
the settlement and growth of foulers, different antifouling coatings have been developed
(Wezembeek et al., 2018), being biocide-based coatings (BC) the most widespread ones.
However, many of these substances have proven to have adverse effects in the environment
(Miller et al., 2020) and unclear effectiveness (Floerl et al., 2005). Thus, ‘non-toxic’
substitutes, such as foul-release (FR) coatings that minimise the adhesion strength, are being
developed. This study aims to assess the effectiveness of two antifouling paint typologies,
simulating in a manipulative experiment the maintenance practices followed by boaters. To
do so, we combined the application of antifouling coatings with maintenance practices,
resulting in 6 types of antifouling strategies.
Materials and methods
The selected study site was the Gulf of La Spezia, on the eastern side of the Ligurian coast.
Following the protocol developed by the Smithsonian Environmental Research Center
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
119
Zoology & Animal Cell Biology Department, University of the Basque Country, PO Box
644, 48080 Bilbao, Basque Country, Spain
E-mail: mar.santos@ehu.eus
TESTING EFFECTIVENESS OF DIFFERENT ANTIFOULING AND BOAT
MAINTENANCE PRACTICES IN THE CONTEXT OF BIOINVASIONS
Abstract
Biofouling, known as the settlement and growth of organisms on wetted surfaces, is one of the major
challenges faced by the boating sector, since it can compromise the hydrodynamics and efficiency of
boats, while contributing to the spread of non-indigenous species (NIS). In this context, different
antifouling solutions have been developed, being the most common ones biocide-based. Although
highly effective, some of these compounds have proven to have adverse effects on the environment.
Thus, new commercially available alternatives have been developed, including non-toxic solutions
focused on altering the surface characteristics of the ship hull. This research aims to test in field
conditions the effectiveness of different antifouling solutions, including paint type (biocide-based; nontoxic; no paint) and maintenance practices (regular hull cleaning; no cleaning). For this purpose, 48
PVC panels with different treatments were submerged in two marinas located in the Gulf of La Spezia
(Italy) and sampled at two different periods. Panels were analysed in the lab to determine how
community structure and composition differed according to the treatment and time, giving special
attention to NIS and initial colonizers. Preliminary results show a significant difference according to
treatment, both at community level and total biomass. Besides, Watersipora subtorquata has been
identified as a biocide resistant organism that facilitates the attachment of others. Further analysis of
the samples will enable to: 1) determine the extent of effects of each of the factors, 2) assess differences
in NIS presence and abundance among factors and 3) suggest best practices for boat maintenance
and point out priorities for biofouling management.
Key-words: biofouling, antifouling paints, bioinvasions, non-indigenous species, recreational boats
Introduction
Fouling communities of recreational boats have proven to be one of the major vectors of
introduction and dispersion of non-indigenous species (NIS) (Ulman et al., 2019). To avoid
the settlement and growth of foulers, different antifouling coatings have been developed
(Wezembeek et al., 2018), being biocide-based coatings (BC) the most widespread ones.
However, many of these substances have proven to have adverse effects in the environment
(Miller et al., 2020) and unclear effectiveness (Floerl et al., 2005). Thus, ‘non-toxic’
substitutes, such as foul-release (FR) coatings that minimise the adhesion strength, are being
developed. This study aims to assess the effectiveness of two antifouling paint typologies,
simulating in a manipulative experiment the maintenance practices followed by boaters. To
do so, we combined the application of antifouling coatings with maintenance practices,
resulting in 6 types of antifouling strategies.
Materials and methods
The selected study site was the Gulf of La Spezia, on the eastern side of the Ligurian coast.
Following the protocol developed by the Smithsonian Environmental Research Center
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
119