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Despite the fact that stowaway transport is an increasingly common invasion pathway, its key ecological aspects, such as colonization dynamics of potential invaders on human transport vectors, are poorly understood. Considering that marinas may function as stepping-stone habitats for the spread of marine invaders, they provide a unique opportunity for understanding the first steps in the stowaway pathway. One of the dominant groups inhabiting marinas are caprellid crustaceans. These small invertebrates have demonstrated a high potential for introduction and establishment far beyond their distribution range. Here, we analyzed the colonization dynamics of caprellid species inhabiting marinas of Cádiz Bay (Spain) on plastic collectors and discussed their implications on invasion success. We found that collectors largely mirrored the resident caprellid community assemblages after just one month of deployment, showing that caprellid species inhabiting marina structures have a high capacity to colonize new artificial substrates. Moreover, the two non-indigenous species found, Caprella scaura and Paracaprella pusilla, successfully established dense and well-structured populations in the collectors (including all sex/age groups considered). We suggest a potential interplay between colonization ability and stowaway organisms’ invasion success. Furthermore, collectors used are supported as a useful tool in the early detection of non-indigenous species and their monitoring in relation to resident species.

Aims: To identify potential hull fouling marine invasive species that could survive in East Antarctica presently and in the future. Location: Australia's Antarctic continental stations: Davis, Mawson and Casey, East Antarctica; and subantarctic islands: Macquarie Island and Heard and McDonald Islands. Methods: Our study uses a novel machine-learning algorithm to predict which currently known hull fouling MIS could survive in shallow benthic ecosystems adjacent to Australian Antarctic research stations and subantarctic islands, where ship traffic is present. We used gradient boosted machine learning (XGBoost) with four important environmental variables (sea surface temperature, salinity, nitrate and pH) to develop models of suitable environments for each potentially invasive species. We then used these models to determine if any of Australia's three Antarctic research stations and two subantarctic islands could be environmentally suitable for MIS now and under two future climate scenarios. Results: Most of the species were predicted to be unable to survive at any location between now and the end of this century; however, four species were identified as potential current threats and five as threats under future climate change. Asterias amurensis was identified as a potential threat to all locations. Main conclusions: This study suggests that the risks are very low, but plausible, that known hull fouling species could survive in the shallow benthic habitats near Australia's East Antarctica locations and suggest a precautionary approach is needed by way of surveillance and monitoring in this region, particularly if propagule pressure increases. While some species could survive as adults in the region, their ability to reach these locations and undergo successful reproduction is considered unlikely based on current knowledge.

Antifouling paints are biocidal products applied to ship and boat hulls in order to prevent the growth and settlement of marine organisms, i.e. fouling. The release of biocides from the surface of the paint film act to repel or poison potential settling organisms. Currently, the most commonly used biocide in antifouling paints is cuprous oxide. In the EU, antifouling products are regulated under the Biocidal Products Regulation (BPR), which states that the recommended dose should be the minimum necessary to achieve the desired effect. For antifouling products, the dose is measured as the release rate of biocide(s) from coating. In this study, the release rates of copper and zinc from eight different coatings for leisure boats were determined through static exposure of coated panels in four different harbors located in Swedish waters along a salinity gradient ranging from 0 to 27 PSU. The results showed the release rate of copper to increase with increasing salinity. Paints with a higher content of cuprous oxide were also found to release larger amounts of copper. The coatings' ability to prevent biofouling was also evaluated and no significant difference in efficacy between the eight tested products was observed at the brackish and marine sites. Hence, the products with high release rates of copper were equally efficient as those with 4 - 6 times lower releases. These findings suggest that current antifouling paints on the market are leaching copper in excess of the effective dose in brackish and marine waters. Additionally, the results from the freshwater site showed no benefit in applying a copper-containing paint for the purpose of fouling prevention. This indicates that the use of biocidal paints in freshwater bodies potentially results in an unnecessary release of copper. By reducing the release rates of copper from antifouling paints in marine waters and restricting the use of biocidal paints in freshwater, the load of copper to the environment could be substa

Because EPA plans to reissue the Vessel General Permit (VGP), the Agency continues to gather information on vessel wastewater sources while examining technologies that can be used to remove pollutants before discharge into waters of the United States. This document contains updated information on recent developments in best management practices (BMPs) for reducing pollutant discharges during underwater ship husbandry., The original document contains color images.

Vessel biofouling is a well recognised modern-day pathway for the transfer of nonindigenous species (NIS). However despite awareness of these risks, marine incursions as a result of vessel biofouling continue to occur at a growing rate. The objective of this thesis is to provide underpinning knowledge to improve pre- and post-border management strategies for vessel biofouling. Chapter 2 provides a baseline assessment of the biofouling extent and assemblage composition on slow-moving vessels arriving at New Zealand's border. Slow-movers were targeted because their operational profile is widely considered to favour the accumulation of extensive biofouling communities (i.e., potentially high risk vectors of NIS). Interestingly, this research revealed low fouling levels and a low incidence of NIS. Highest levels of fouling were observed in areas where antifouling paint condition was poor or absent (e.g., dry-docking support strips and niche areas), which is consistent with recent studies of biofouling on other vessel types. Despite these findings, there have been several documented examples where heavily fouled slow movers have had high risk NIS on them. As such, risk profiling of slow-moving vessels is recommended. This should be based on operational characteristics such as maintenance history, exposure to regions where pest species are known to be present and intended vessel movements in the recipient region, and should ideally be undertaken on a case-by-case basis prior to arrival from international or distant source-regions. There are limited biofouling risk mitigation options available upon the discovery of NIS at the border, particularly for large vessels (e.g., barges) or towed structures (e.g., oil rigs) where removal to land is often not feasible and in-water defouling may be the only option available. Chapter 3 provides a conceptual framework that identifies biosecurity benefits and risks posed by in-water defouling. Among the latter are the survivorship of de

Macroalgae are a significant component of historic and modern invasions, with association to a wide variety of transport mechanisms. These transport mechanisms pose specific constraints on the ways by which species can be taken up, transported and released into a new environment. Currently operating transport mechanisms for marine macroalgae are either associations with intentional introductions (translocations for aquaculture, aquarium or live seafood trade) or accidental introductions (mainly as hull-fouling). A number of potential management options exist, including the development of international instruments and regional agreements. The development of treatment options for hull fouling, the most significant and poorly managed transport mechanism for macroalgae, is of urgent need. Our current ability to identify which species are likely to invade next is limited. However, an examination of the synergies between species' functional traits, transport constraints, and recipient community attributes will likely provide possible options in the future.

Macroalgae are a significant component of historic and modern invasions, with association to a wide variety of transport mechanisms. These transport mechanisms pose specific constraints on the ways by which species can be taken up, transported and released into a new environment. Currently operating transport mechanisms for marine macroalgae are either associations with intentional introductions (translocations for aquaculture, aquarium or live seafood trade) or accidental introductions (mainly as hull-fouling). A number of potential management options exist, including the development of international instruments and regional agreements. The development of treatment options for hull fouling, the most significant and poorly managed transport mechanism for macroalgae, is of urgent need. Our current ability to identify which species are likely to invade next is limited. However, an examination of the synergies between species' functional traits, transport constraints, and recipient community attributes will likely provide possible options in the future.