Fouling Communities Research Articles

Data-driven approach to evaluate the impact of hull roughness on main engine load of river-sea ships

Hull roughness increases the ship's resistance during navigation, significantly increasing fuel consumption and emissions. The study proposed the hull fouling factors (HFFs) to evaluate the time-varying impact of hull roughness on main engine load (MEL) for the three bulk carriers. Initially, ships' Automatic Identification System data, operational data, and weather and sea state data were fused to develop predictive models for MEL. Specifically, the Random Forest (RF) model outperformed others in predicting MEL. Then, by adopting a controlled variable experiment, the RF model was utilized to evaluate the impact of hull roughness on MEL as the days since clean (DSC) increased. Hull roughness analysis results showed that the HFFs of ship operated primarily on sea routes showed an increasing trend with the increasing DSCs. In contrast, the HFFs of ships primarily operated on the river-sea routes did not change significantly. The approach revealed significant temporal variations in hull roughness for ships operating in different routes. Besides, the proposed HFFs could capture the impact of sea temperature, salinity, current velocity and ship speed on hull roughness. Overall, the finding provides new insights into the time-varying hull roughness impacts on sea-to-river ships, and supports hull cleaning strategies, energy management and emission estimates.

Detecting Hull Fouling using Machine Learning Algorithms trained on Ship Propulsion Data to Improve Resource Management and Increase Environmental Benefits

Detecting Hull Fouling using Machine Learning Algorithms trained on Ship Propulsion Data to Improve Resource Management and Increase Environmental Benefits

Fluxes of nitrogen and phosphorus in fouling communities on artificial offshore structures

The number of offshore artificial structures in the North Sea is continuously increasing. Apart from the structures that have been added to the marine environment accidentally (e.g., shipwrecks), structures are also deliberately developed to meet the increasing needs for renewable energy. These structures provide habitat for fouling organisms. The fouling communities vary in abundance and composition based on location, depth, and structure age. Most fouling species filter particles from the water column, changing phytoplankton production and affecting larval settlement success, while releasing ammonium that can fuel phytoplankton growth as well as (pseudo)faeces that enriches the seabed, changing local biogeochemical cycles.Our study used in-situ incubation chambers to investigate oxygen, nitrogen, and phosphate fluxes associated with fouling organisms to improve understanding of these changes in biogeochemical cycles. Divers used incubation chambers (domes) on shipwrecks in the southern North Sea where over 55 years mature fouling communities have established. A series of water samples was collected from each dome during deployment to measure the change in concentration of ammonium, nitrite, nitrate, and phosphate. All fauna enclosed in the domes was collected after each measurement for further analysis.The full macrofauna dataset contained 65 unique species on 4 shipwrecks (25 to 50 species per sample). Abundance ranged from 2187 to 59,427 individuals per sample (683 cm2). On average, a decrease in oxygen concentration of 126 μmol/g ash free dry weight/h was found. The sequential water samples also showed clear changes in nutrient concentration with time in all incubations. The largest changes were observed with high fouling community abundances and biomass. Ammonium, nitrite, and phosphate always increased, with 1.5-to-5-fold increases from start to end of the incubation, while for nitrate both an efflux and influx were measured. Oxygen decreased in all incubations. Mean fluxes (all in μmol per m2 per hour with standard error) were significant for ammonium (945 ± 300), nitrite (80 ± 30), phosphate (61 ± 8), and oxygen (−11,794 ± 3289), but not for nitrate (−206 ± 122). Per gram AFDW, only ammonium (12.7 ± 3.5) and oxygen (−126 ± 48) had fluxes that differed significantly from zero.Compared to average seabed (sandy bottom) oxygen demand and community fluxes from previous studies, the observed fluxes were high. Our findings resembled those from temperate biogenic reef studies. Further data collection across a larger spatial and temporal scale is needed to fully understand offshore structure effects on marine environments.

A reciprocal transplant approach to predation in fouling communities found in natural and artificial habitats

Human influence along the coastline is a significant threat to biodiversity and includes the alteration or replacement of natural habitat with artificial structures. Infrastructure such as docks and marinas are common throughout the world and typically have negative impacts on coastal flora and fauna. Impacts include the reduction of native biodiversity, the increase of introduced species, and the alteration of biotic interactions (e.g., predation). Many studies examine human disturbance on biotic interactions within a single habitat (i.e., docks or marinas) but what lacks are paired comparisons using standardized methods of biotic interactions between artificial and nearby natural habitats. In the current study, benthic fouling communities were allowed to develop, with and without predator access, in artificial and seagrass habitats. Cages were used to reduce predation and removed to expose communities to fish predators. Prior to exposure, communities were either left at their original site or transplanted to the opposite habitat and changes in the percent cover of species found were compared. Initially, community composition differed between habitats and when predation was reduced (caged vs. open). When developed communities within cages were exposed to predators, predation was strong but only in artificial habitats and regardless of where communities originated. In contrast, little predation occurred at seagrass sites on previously caged communities developed within seagrass beds or that were transplanted from artificial habitat. Taken together, results indicate that the strength of biotic interactions can differ depending on habitat, leading to changes in community composition. With the continuous expansion of artificial structures world-wide, it is becoming increasingly important to understand not only their effects on biotic interactions and biodiversity but also how these effects extend and compare to adjacent natural habitats.

Interpretable, data-driven models for predicting shaft power, fuel consumption, and speed considering the effects of hull fouling and weather conditions

In response to the global call for action to reduce CO2 emissions, operational measures such as speed, route optimization, and hull cleaning play a significant role in the maritime industry. These measures can be implemented immediately without significant investment in both newbuilding ships and existing ships. To make accurate decisions regarding operational measures, reliable and precise models of environmental conditions and effects of hull fouling are required. In this study, a data-driven approach using linear regression was applied to predict shaft power, fuel consumption, and speed after intensive data preparation and feature engineering. First, a shaft power prediction model was developed by combining three independent submodels: the RPM-power model, hull fouling model, and environmental effect model. Subsequently, fuel consumption and speed prediction models were developed based on the shaft power prediction model. Model validation was performed on a 174K LNG carrier, and the results showed good accuracy even in long-term ship operations of more than two years. The mean absolute percentage errors (MAPEs) of the prediction models were 1.60%, 1.70%, and 2.68% for the shaft power, fuel consumption, and speed, respectively. The validated models were applied to two LNG carriers, and satisfactory results were obtained. This study contributes to greenhouse gas (GHS) reduction by providing interpretable, flexible, and accurate models that can help make correct decisions regarding optimal operational measures.

Fouling community composition on a pilot floating solar-energy installation in the coastal Dutch North Sea

The increasing need for renewable energy has led to the transition of renewable energy devices to the marine environment. Currently, mainly offshore wind farms have been completely developed and are operational in the North Sea. The solar energy sector is also rapidly evolving and floating photovoltaics are continuously created and deployed. In this study, we investigated the colonisation patterns and community changes with time of fouling fauna on the first floating photovoltaics in the coastal Dutch North Sea. Samples were collected by divers from the underwater side of 4 floaters, coated with different anti-fouling techniques (Intersleek, GreenPowerNano PPDura, Finsulate and Pato) at two different moments, shortly after the deployment of the floaters and approximately a year later. In total, 72 fouling taxa were identified on the floaters, from which ca. 11% are known to be non-indigenous species for the region. The anti-fouling coating Intersleek seemed to work the most efficiently against fouling colonisation, since the fouling community sampled from this floater contained the least taxa. However, the small number of samples collected from the different floaters did not allow for a direct comparison between the anti-fouling coatings. The communities evolved with time, with young communities accommodating a larger number of individuals and old communities having less individuals but higher biomass, indicating that the organisms become bigger in size and compete for the available space. Nevertheless, the communities had not reached a stable climax yet, while this process might take multiple years due to the dynamic environment in which floating photovoltaics are deployed. Monitoring the fouling communities occurring on floating photovoltaics in the North Sea for a long-term is necessary to understand the effects of these new man-made structures on the marine environment, especially since floating photovoltaics are moving to offshore locations and will be possibly co-located with offshore wind farms in the future.

Quick spreading of the exotic amphipod Laticorophium baconi (Shoemaker, 1934): another small stowaway overlooked?

Studies of non-indigenous species (NIS) often tend to focus on medium and large-sized taxa with potential for remarkable ecological and/or economic impact, whereas the early detection of small invertebrates is often delayed due to taxonomic challenge, lack of consistent, standardised monitoring efforts and limited funding. This study represents the first records of the marine amphipod Laticorophium baconi (Shoemaker, 1934) in Morocco, Tunisia, Corsica (France), Italy, Greece, Egypt, Saudi Arabia and New Caledonia (France). Furthermore, it reports an expansion of its known distribution in Portugal (earliest and northernmost record for the country and first record for Macaronesia), Spain (earliest record for Atlantic and Mediterranean European waters), and Australia (first record for Indian Ocean). Recreational boating and commercial shipping, mainly through hull fouling and secondarily ballast waters, are proposed as vectors for introduction and secondary spread of L. baconi. The following traits, analysed during the present study, could contribute to its invasive potential: (i) quick and extensive spread of the species worldwide, (ii) high densities in marinas, harbours, hull fouling and other artificial habitats, including aquaculture facilities and floating debris, (iii) high ability for short-term colonisation of empty artificial niches, (iv) diet based on detritus suggesting an opportunistic feeding behaviour, and (v) population survival during seasonal fluctuations in different regions. Taxonomic expertise and scientific collaboration, based on multidisciplinary networks of experts, are crucial for the early detection, distribution updates, and risk assessment of small and overlooked stowaways in marine environments.

Exploring foraging preference of local fish species towards non-indigenous fouling communities near marinas: Insights from Remote Video Foraging System (RVFS) trials

Non-indigenous species (NIS) spread from marinas to natural environments is influenced by niche availability, habitat suitability, and local biotic resistance. This study explores the effect of indigenous fish feeding behaviour on NIS proliferation using fouling communities, pre-grown on settlement plates, as two distinct, representative models: one from NIS-rich marinas and the other from areas outside marinas with fewer NIS. These plates were mounted on a Remote Video Foraging System (RVFS) near three marinas on Madeira Island. After 24-h, NIS abundance was reduced by 3.5 %. Canthigaster capistrata's preference for marinas plates suggests potential biotic resistance. However, Sparisoma cretense showed equal biting frequencies for both plate types. The cryptogenic ascidian Trididemnum cereum was the preferred target for the fish. Our study introduces a global framework using RVFS for in-situ experiments, replicable across divers contexts (e.g., feeding behaviour, biotic resistance), which can be complemented by metabarcoding and isotopic analysis to confirm consumption patterns.

Influence of propeller fouling on propulsion performance of an actual ship: a long-term analysis focusing on the power for keeping propeller’s rotation of a controllable pitch propeller

This study focuses on the shaft power at the neutral angle of a controllable pitch propeller to analyze the change in the required power due to propeller fouling. It is named and defined as a power for keeping propeller’s rotation (RP) because a propeller does not generate the net thrust to push the hull but dissipates the power to keep its constant speed. Statistical analysis was conducted using a decade of the observed data from a research vessel. This study assumed that the change in RP can be considered as an indicator showing the state of propeller fouling. In addition, the state of fouling on the hull can be estimated indirectly based on RP because the data correlated the shaft power under several operating conditions with RP on the same voyage. The fouling state was classified into three conditions based on RP. The comparison of shaft power at the same ship speed between the clean condition and the serious fouled condition showed that the shaft power was increased by 35% on average due to fouling. When the ship navigates under 10 knots, propeller fouling has a larger impact on the increase in shaft power than hull fouling.

EDNA Metabarcoding Analysis as Tool to Assess the Presence of Non-Indigenous Species (NIS): A Case Study in the Bilge Water

One of the most important causes of biodiversity loss are non-indigenous species (NIS), in particular invasive ones. The dispersion of NIS mainly depends on anthropogenic activities such as maritime traffic, which account for almost half of the total NIS introduction in the European seas, as reported by the European Environmental Agency. For this reason, NIS management measures are mainly focused on commercial ports (i.e., ballast water management and Marine Strategy Framework Directive monitoring), underestimating the role of marinas and tourist harbors; these host small vessels (<20 m), such as recreational, fishery, and sail ones without ballast waters, but are also responsible for NIS arrival and spread through the bilge water as well as from hull fouling. With the aim of paying attention to marinas and tourist harbors and validating an innovative molecular methodology for NIS surveillance and monitoring, in the present work, eDNA metabarcoding of cytochrome oxidase subunit I (COI) was applied to both bilge waters and adjacent ones to assess species composition and particularly NIS presence. A total of 140 OTUs/species with extra-Mediterranean distribution were found in the bilge samples; several of these are most likely ascribed to food contamination (e.g., Salmo salar). Excluding food contamination species, twelve of these found in the bilge waters were already known as NIS in the Mediterranean Sea, belonging to algae, mollusks, crustaceans, annelids, echinoderms, and fishes. Nine of these species are new to Italian waters. The results obtained in the present work support the importance of NIS monitoring in marinas and small harbors, particularly in the bilge waters, through eDNA metabarcoding, having detected several potential NIS that otherwise would not have been discovered.

The effect of surface orientation on early successional fouling communities in the southern gulf of Maine

Artificial environments have hard surfaces positioned at different orientations that attract a wide diversity of sessile invertebrate species, forming fouling communities. Fouling communities play a large role in the spread of a species introduction, as organisms gain purchase in artificial environments and use them as a stepping-stone into neighboring natural systems. These man-made systems harbor a large diversity of species, and there are often vastly different communities present on both vertical and horizontal surfaces. We used a species abundance dataset at three time periods spanning 30 years, collected from fouling panels in a high tidal flow estuary at the mouth of the Piscataqua River (New Castle, New Hampshire) in the southern Gulf of Maine to measure differences in community composition between horizontal and vertical panels. Early successional communities on settlement panels were photographed one year after installment in late summer to capture the highest diversity seasons. Organisms were then identified to the lowest taxonomic level, and communities on the underside of horizontal and vertical panels were compared. Vertical and horizontal communities from 1980 and 2004 were similar, while those from 2009 statistically differed from one another. Vertical and horizontal surfaces in the 1980s were dominated by the blue mussel Mytilus edulis, which declined in later years, and was replaced by invasive ascidians. Species diversity increased between the 1980 and 2004 sampling, but declined by the 2009 sampling. This study captures changes of species composition in early successional communities on vertical and horizontal surfaces at a single locale from three time periods spanning over 30 years.

Non-native coral species dominate the fouling community on a semi-submersible platform in the southern Caribbean

A coral community was examined on a semi-submersible platform that was moored at the leeward side of Curaçao, in the southern Caribbean, from August 2016 until August 2017. This community included several non-native or cryptogenic species. Among them were two scleractinian corals (Tubastraea coccinea and T. tagusensis) and two octocorals (Chromonephthea sp. and an unidentified Nephtheidae sp.). This is the first reported presence of T. tagusensis in the southern Caribbean, and the genus Chromonephthea in the Caribbean region. An ascidian, Perophora cf. regina, is also reported from the southern Caribbean for the first time, as well as a coral-associated vermetid gastropod, Petaloconchus sp., first recorded in the Caribbean in 2014. Lack of biofouling management could potentially harm indigenous marine fauna through the introduction of non-native species. Therefore monitoring communities associated with semi-submersible platforms is essential to track the presence and dispersal of non-native, potentially invasive species.

Tank fouling community enhances coral microfragment growth.

Anthropogenic stressors threaten reefs worldwide and natural in situ coral reproduction may be inadequate to meet this challenge. Land-based culture can provide increased coral growth, especially with microfragments. We tested whether culture methods using different algal fouling communities could improve the growth and health metrics of microfragments of the Hawaiian coral, Porites compressa. Culture method fouling communities were: (1) similar to a reef environment (Mini Reef); (2) clean tanks managed to promote crustose coralline algae (Clean Start); and (3) tanks curated beforehand with poorly-competing algae (Green Film) assessed in winter and summer months. The Green Film method during the winter produced the fastest microfragment mean growth at 28 days until the first row of new polyps developed, and also the highest tank and plate metric health scores. Time efficient, standardized methods for land-based culture designed to maximize growth and production of coral fragments will contribute considerably to the success of large-scale restoration efforts.

New species and new records of bryozoan species from fouling communities in the Madeira Archipelago (NE Atlantic)

Hull fouling is considered to be the most significant vector of introduction of marine non-indigenous species (NIS) in the Madeira Archipelago (NE Atlantic) because these islands provide a vital passage route for many ships. The transfer of species between boat hulls and artificial substrates in marinas is known to be high. Bryozoans are among the most common groups of marine invertebrates growing on this type of substrate. In recent years, significant advances have been made in our knowledge about the biodiversity of bryozoans in the Madeira Archipelago. Nonetheless, the currently recognized numbers remain far from reflecting the actual bryozoan species richness. In this context, we examine bryozoan samples stemming from NIS monitoring surveys on artificial substrates along the southern coast of the Madeira Archipelago, in four recreational marinas and in two offshore aquaculture farms. This has yielded new information about ten bryozoan species. Two of them, Crisia noronhai sp. nov. and Amathia maderensis sp. nov., are described for the first time, although at least the first one was previously recorded from Madeira but misidentified. Bugula ingens, Cradoscrupocellaria insularis, Scruparia ambigua, and Celleporaria brunnea are recorded for the first time in Madeira. Moreover, the material of C. brunnea was compared with the type, and a biometric analysis was performed with material from the Atlantic and Mediterranean. All samples identified as C. brunnea in both regions are the same species, and the variations described in the literature apparently reflect high intracolonial variability. Finally, we provide new information for the descriptions of 4 additional bryozoans, namely, Crisia sp. aff. elongata, Cradoscrupocellaria bertholletii, Scrupocaberea maderensis, and Tricellaria inopinata.

Impact of Hull Fouling on Vessel’s Fuel Consumption and Emissions Based on a Simulation Model

With an ever-increasing trend of analysing and improving vessel energy and economic efficiency in recent years and decades, every aspect of a vessel’s system needs to be observed with the goal of reducing fuel consumption and emissions. Hull fouling can have a significant effect on these variables. Since hull maintenance is an expensive effort, its use must be optimized and fine-tuned to increase the economic efficiency of a vessel’s exploitation cycle. In order to do this, data and a subsequent analysis have to be obtained on different stages of the hull fouling process and the effect these states have on vessel energy efficiency and consequently emissions and economic efficiency. This paper will analyse a set of data including emission pollutants such as nitrogen oxides (NOX) and carbon dioxide (CO2) as a greenhouse gas and the effect that different amounts of hull fouling have on the vessel’s fuel consumption and emissions under different propulsion loads. The aforementioned data is obtained from a simulation model of a RoPax vessel. The advantage of using data from a simulation model of a RoPax vessel for the research discussed in this paper is the ability to analyse various conditions not easily reproduced on actual ships. Main research findings presented in this paper are consistent in proving that increased hull fouling leads to increased fuel consumption and emissions as high as 15% increase in extreme cases. Keywords: hull fouling, fuel consumption, pollutant, greenhouse gas, emissions, simulator

CATAIN: An underwater camera system for studying settlement in fouling communities at high temporal resolution

AbstractAt present, studies on settlement in marine fouling communities are limited to easily accessible habitats that can be monitored on a daily basis. There are large knowledge gaps regarding settlement patterns on sub‐daily temporal scales and in remote areas. In order to fill these knowledge gaps, we have designed an underwater camera system named CATAIN—CAmera To Analyze INvertebrates—and have compared our approach to standard methods. The key innovation of CATAIN is that the acrylic endcap of the housing serves as the fouling panel itself, with organisms being photographed through the transparent endcap from the underside. This set‐up circumvents the common problem of biofouling on camera housings. Using this system, researchers can record high‐resolution images of sessile benthic invertebrates and macroalgae at time intervals ranging from just a few minutes to several days and for months to a year at a time. CATAIN enables studies on temporal patterns in settlement, postsettlement mortality, growth, and other ecological parameters with no human intervention. This system expands sampling possibilities in remote environments where it is impractical for a researcher to be present every day.

Marine vessel energy efficiency performance prediction based on daily reported noon reports

ABSTRACT The marine vessel performance is quite critical in the maritime applications. In addition to internal variables like fuel, propulsion type, and loading condition, external factors such as fouling, sea state, currents, and more affect ship performance. The goal of this study is to create a model to predict ship slip rate based on specified noon report data which contain sea, wind, WED, and, DAS. 30 different noon report values of a crude oil tanker have been conducted on the same route with similar loading condition and they have been analysed by the MLR and the ANN respectively. Although a meaningful relationship between the variables couldn’t create among the variables by the MLR, predicted ship slip values are very close to the verified ones in the ANN. Minor differences could be caused by changes in the amount of hull fouling, vessel loading conditions, reverse or different currents, quite unsettled weather, and sea conditions.

Cardiovascular responses to increased temperature and lower pH for six cold water Opisthobranch species

Increasing sea surface temperatures and ocean acidification continue to threaten marine life globally, especially in coastal waters where effects are often exacerbated. Individually, temperature and acidification negatively affect marine organisms, but interactive effects, vary depending on phylum and life cycle stage. Opisthobranch sea slugs, having short and complex life cycles, were studied for cardiac response to increasing temperature and to interactive effects of temperature and pH. Six cold-water, cosmopolitan species (Aeolidia papillosa, Cuthona gymnota, Dendronotus frondosus, Flabellina verrucosa, Onchidoris bilamellata, and Placida dendritica) common in the Gulf of Maine were selected. To determine response to temperature, heartbeats of test animals starting at 4 °C were recorded at increasing temperature intervals of 4 °C, until they slowed or ceased. Interactive effects were examined at pH 8 (control) and pH 7 coincident with temperature increases (4o to 16 °C). Overall, upper pejus temperatures tested ranged from 16o to 28 °C, with the largest species having the lowest temperature threshold and smallest having the highest. Although interactive effects were not significant, the negative synergistic effect of suppressed heart rate across temperatures was significant for three species and apparent in two others. As significant predators of sessile prey, especially within fouling communities, environmental impacts on sea slugs have the potential to alter both community structure and prey abundance within their environment, potentially reflecting larger implications affecting the biodiversity and abundance of prey populations within their environment.

A conceptual basis for surveying fouling communities at exposed and protected sites at sea: Feasible designs with exchangeable test bodies for in-situ biofouling collection

The enhanced inertia load caused by biofouling on device components, such as the foundations of wind turbines or other structures at sea, modifies the hydrodynamic properties, and increases the stress to structures, predominantly in upper water layers with high impact from wave dynamics. This compromises the stability, functioning, operation as well as the durability of these devices especially in exposed environments. A main challenge is the quantification of the impact of hydrodynamic forces on irregular bodies being overgrown by soft- and hard-bodied biofouling organisms. Therefore, test bodies from the upper 1–5 m water depth and thus exposed to the strongest wave actions close to the surface shall be overgrown by biofouling and used in measurement trials in a wave and current flume. These measurements shall shed light on the varying roughness and its influence on the load bearing capacity of foundation piles. Consequently, the main aims of the present work were the development of two independent test stations as holding devices for artificial test bodies for the collection of biofouling organisms during field studies: a carrying unit floating at the surface in an exposed area (System A) and a sampling device with access from a land-based facility (System B). Both systems are relatively easy to access, exhibit straightforward handling, and are reasonable cost-effective. A Test Body Support Unit (TBSU, System A) was designed and mounted on a spare buoy to carry the test bodies (cylinders), which serve as substrate for the fouling. The system was sufficiently robust to withstand several periods of rough sea conditions over the first two years. This system can only be accessed by vessels. System B (MareLift) provided the robustness and functionality needed for areas exhibiting harsh conditions but can be operated from land. The here used test bodies (steel panels) exhibited a sound basis for the monitoring of succession processes in the biofouling development. System B offered the possibility to analyse two habitats (intertidal and subtidal) and revealed clear differences in the composition and development of their fouling communities.Overall, both systems provide advantages in obtaining standardized biofouling samples compared to previous approaches. Such test stations play an important role in the risk management of marine sectors as they could help characterising biofouling communities over different geographical areas. System A and B provide a sound basis for biofouling research but potentially also for other potential research approaches in exposed areas as they provide space for future developments.

Fouling Community on Pinna nobilis Larval Collectors in the Adriatic—Impact of Invasive Species

In the last few years, the endemic Mediterranean bivalve Pinna nobilis has been exposed to dramatic mortality in its entire area, which could lead to the extinction of the species. Throughout the Mediterranean, a lot of effort is being put into finding ways of preserving it. One of the methods used to monitor recruitment and juveniles’ survival is the installation of collectors for bivalve larvae. We installed collectors at two locations: in Brijuni National Park (North Adriatic) and Luka Cove (central Adriatic). Our aim was to compare the fouling community on the collectors in two consecutive years (2019 and 2020), especially because the installation of collectors in 2020 coincided with mass mortality events of P. nobilis in the area. The number and size of juvenile P. nobilis and the qualitative and quantitative composition of the fouling communities were determined. The results show a reduction in the number and size of juvenile P. nobilis and an explosion of the invasive bivalve Anadara transversa population on collectors in the second year. In Luka Cove, another invasive species—the ascidian Styela plicata—also seriously affected other organisms on the collectors to the point of preventing analysis of the fouling community.