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Biofouling is a significant means for introducing non-indigenous marine species internationally, which can alter habitats and disturb marine ecosystems. This study estimated the flux of ships' wetted surface area (WSA) to Korea in 2020 to assess the risks of biological invasion via biofouling on ships' hulls. The annual total WSA flux entering Korea was estimated to be 418.26 km2, with short-stay vessels (<3 weeks) contributing to 99.7% of the total WSA flux. Busan and Ulsan ports were identified as the main sources of high-risk flux, with container ships being a major vector in Busan and tankers in Ulsan. Gwangyang port had the third-highest total WSA flux, with nearly half of the flux driven from coastwise voyages, making it particularly vulnerable to the spread of hull fouling organisms. These findings could help enhance the management and inspection of hull fouling organisms in Korea. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Ship biofouling is a major vector for the introduction and spread of harmful marine species globally; however, its importance in Arctic coastal ecosystems is understudied. The objective of this study was to provide insight regarding the extent of biofouling (i.e., percent cover, abundance, and species richness) on commercial ships operating in the Canadian Arctic. A questionnaire was used to collect information on travel history, antifouling practices, and self-reported estimates of biofouling extent from ships operating in the region during 2015–2016. Twenty-five percent of ships operating in the region during the study period completed the questionnaire (n = 50). Regression trees were developed to infer the percent cover of biofouling, total abundance of fouling invertebrates, and fouling species richness on respondent ships based on previous underwater wetted surface assessments of commercial ships in Canada. Age of antifouling coating system was the only significant predictor of percent cover and total abundance of biofouling invertebrates, while the number of biogeographic realms previously visited and port residence time were significant predictors for fouling species richness. Comparison of relevant travel history features reported through the questionnaire to the regression tree models revealed that 41.9% of 43 respondent ships had antifouling coating systems older than 630 days and are therefore inferred to have relatively high (> 9.3%) biofouling percent cover. More than half of respondent ships (62.8%) had antifouling coating systems older than 354 days and are therefore inferred to have a relatively high total abundance (over 6,500 individuals) of fouling invertebrates. Nearly half of respondent ships (45.9% of 37 ships) had visited at least three biogeographic realms during their last 10 ports-of-call and are therefore inferred to have relatively high fouling species richness (mean 42 taxa). Self-reported estimates of biofouling cover were unreliable, being much lower than model inferences. Although the regression tree models have relatively low predictive power, explaining only 15–33% of the variance in biofouling extent, this study indicates that commercial ships are an active pathway for the transportation of non-indigenous aquatic species to Canadian Arctic coastal ecosystems via biofouling.

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.

Despite the importance of dispersal behavior in the eco-evolutionary responses of species to global environmental change, its role in the invasion dynamic of stowaway invaders has been poorly studied, especially in low-mobile species (i.e. with direct development). Here we use peracarid crustaceans as a target group to understand the role that local dispersal plays in the initial stages of the stowaway pathway in species inhabiting transport hubs (specifically marinas). Thus, we performed field experiments to quantitatively explore differences in species' propensity to disperse when comparing species with low and high invasion potential (considered here as the ability for successful anthropogenic dispersal). At the community level, we found that widespread introduced species (with high potential for invasion; HPI) exhibited higher propensity for local dispersal than closely related species that fail to spread (with low potential for invasion; LPI). From a functional perspective, high invasion potential, in synergy with omnivorous feeding and a tube-dweller lifestyle, was instrumental in determining differences in trait composition between assemblages that vary in their natural tendency to disperse. In addition to anthropogenic dispersal on ships, we show that unaided dispersal may play a crucial role at the beginning of the stowaway pathway, even in low-mobile species. Knowledge of dispersal behavior should be more fully integrated into research on managing the risk of this growing invasion pathway. This may help to predict rates of spread and provide new insights into the proximate causes of stowaway organisms' invasion success. [ABSTRACT FROM AUTHOR]

The Southwestern Atlantic is often perceived as remote region, yet it is not immune to biological invasions. Patchy information on historical community composition hinders our ability to identify introductions to coastal ecosystems in this region. Hull fouling is an under-managed shipping vector that likely continues to transport large numbers of marine species worldwide. The port of Mar del Plata is a comparatively well-studied shipping and commercial hub that may serve as an observatory to monitor new introductions to the Argentine coast. Following detection of nonindigenous isopods during preliminary port sampling in 2007–2008, we organized regular port surveys aimed at assessing the level of population establishment and evaluated hull fouling as a potential introduction vector in the Port of Mar del Plata. In 2011–2012, we conducted 12 monthly dive surveys of port isopod communities in combination with three opportunistic surveys (two in-water, one in dry-dock) of hull fouling communities attached to a domestic research vessel during consecutive port calls at its base in this port. Replicate biofouling samples from underwater dock structures and the vessel's hull were collected by scraping invertebrates in 20 × 20 cm quadrats (even surfaces) and 1000 cm 3 of biofouling organisms (uneven surfaces). Both in port- and hull-fouling communities, we discovered the presence of the nonindigenous isopods Dynamene edwardsi and Paracerceis sculpta . This report constitutes the first detection of these two global marine invaders in American and Argentine waters, respectively. They likely represent relatively recent introductions to this corner of the world's oceans, yet our data indicate that both species are currently well established in Mar del Plata. These results demonstrate (for the first time in the case of D. edwardsi ) the potential for hull fouling to disperse both species, and raise a warning on their potential expansion to other Southwestern Atlantic ports and Antarctica in a near future. Research on the marine communities of the Southwestern Atlantic is pressingly needed to establish pre-invasion communities and detect new introductions. Simultaneous surveillance of ports (invasion hubs) and vessels (vectors) can effectively detect invaders and inform prevention efforts in this region. [ABSTRACT FROM AUTHOR]

Aim The Panama Canal expansion, scheduled for completion in 2015, is expected to have major effects on commercial shipping and port operations throughout the world, with potential consequences for the transfer and establishment of non-indigenous species that remain largely unexplored. We developed a series of scenario-based models to examine how shipping traffic patterns may change after expansion and consider possible implications for species transfers and invasion dynamics in the USA. Location Coastal USA, excluding Alaska and Hawaii Methods Using a Monte Carlo simulation approach, we predicted changes in discharged ballast water, wetted surface area of ship hulls and frequency of ship arrivals modelled under scenarios that are based on (1) current shipping patterns from the western Pacific Rim to the USA, (2) estimates of fleet expansion and (3) diversion of traffic away from the US West Coast through the Panama Canal. Results During the 5-year period following canal expansion (2015-2019), our models estimated that the Gulf and East coasts would receive 78% and 99% median increases in total ballast discharge and 172% and 182% increases in total wetted surface area, respectively. For the West Coast, our models estimated 9.6% median decreases in both total ballast discharge and wetted surface area. We further predict that many ports in the Gulf and East coasts will receive up to three times the current number of arrivals and increased ballast water discharge, from this region after expansion. Main conclusions Our scenario-based analysis provides a first estimate for increases in frequency, magnitude and spatial distribution of exposure that the Gulf and East coasts will experience due to ships and ballast arriving from the western Pacific, following the canal expansion. If organisms transported via ballast water or ship hulls are able to survive transit of the canal, the predictions suggest increased likelihood of introduction along these coasts by species originating in the western Pacific. [ABSTRACT FROM AUTHOR]

Abstract: This study examined the efficacy of heated seawater for the treatment and remediation of fouled vessel sea chest habitats. In laboratory trials, three temperature regimes (37.5°C for 60min, 40°C for 30min and 42.5°C for 20min) were tested on a range of temperate taxa commonly found in sea chests. Field validation trials further assessed the efficacy of heat treatment within a replica sea chest environment. During laboratory trials, 100% mortality was achieved across all three treatments for the majority of taxa; the exceptions being the barnacle Elminius modestus and the oyster Crassostrea gigas. Temperature tolerance limits observed in the laboratory were successfully replicated under simulated sea chest conditions; however, a failure to achieve even heat distribution was an obstacle to achieving uniform mortality. This study provides guidance on the temperature/exposure parameters required for vessels plying temperate latitudes, and demonstrates that heated seawater has potential for controlling biofouling in vessel sea chests. [Copyright &y& Elsevier]

Vessel traffic is the primary pathway for non-indigenous marine species introductions to New Zealand, with hull fouling recognised as being an important mechanism. This article describes hull fouling on seven slow-moving commercial vessels sampled over a 1 year period. Sampling involved the collection of images and fouling specimens from different hull locations using a standardised protocol developed to assess vessel biofouling in New Zealand. A total of 29 taxa was identified by expert taxonomists, of which 24% were indigenous to New Zealand and 17% non-indigenous. No first records to New Zealand were reported, however 59% of species were classified as ‘unknown’ due to insufficient taxonomic resolution. The extent of fouling was low compared to that described for other slow-movers. Fouling cover, biomass and richness were on average 17.1% (SE = 1.8%), 5.2 g (SE = 1.1 g) and 0.8 (SE = 0.07) per photoquadrat (200 × 200 mm), respectively. The fouling extent was lowest on the main hull areas where the antifouling paint was in good condition. In contrast, highest levels of fouling were associated with dry-docking support strips and other niche areas of the hull where the paint condition was poor. Future studies should target vessels from a broader range of bioregions, including vessels that remain idle for extended periods (ie months) between voyages, to increase understanding of the biosecurity risks posed by international commercial slow-movers. [ABSTRACT FROM PUBLISHER]

Aim  Hull fouling is a leading vector for the introduction of marine, non-indigenous species (NIS) worldwide, yet its importance to freshwater habitats is poorly understood. We aimed to establish the complement of NIS transported via this vector to the Great Lakes and to determine if they pose an invasion risk. Location  Laurentian Great Lakes. Methods  During 2007 and 2008, we collected scrapings from exterior surfaces as well as underwater video-transects from 20 vessels shortly after their arrival in Great Lakes’ ports. Invertebrates present were sorted and identified in the laboratory. Results  Total estimated abundance averaged > 170,000 invertebrates per ship belonging to 109 taxa. Most (72%) of these taxa were freshwater species already present in the Great Lakes, whereas 11 and 31% were native to estuarine and marine habitats respectively, and would not be expected to survive in this habitat. Abundance was dominated by barnacles (51%), cladocerans (19%), bivalves (12%) and amphipods (11%). Sea-chest grating and the rudder were hot-spots for biofouling. Invertebrate diversity and total abundance were positively associated with total time spent in port during the last year and time in Pacific South American ports and negatively related to time in high latitudes and sailing speed. Although we found some live, established invaders such as Gammarus tigrinus and Dreissena rostriformis bugensis, only one individual of a freshwater NIS ( Alexandrovia onegensis, Oligochaeta) not yet reported in the Great Lakes was detected. The animal’s poor condition and seemingly low population abundance indicated the risk of live introduction by this vector was likely quite low. Main conclusion  Our results indicate that hull fouling appears to pose a low risk of introductions of new species capable of surviving in the Great Lakes, unlike foreign-sourced freshwater ballast water that historically was discharged by these transoceanic vessels. [ABSTRACT FROM AUTHOR]

1. Biological invasions are characterized by occasional long-distance, human-assisted dispersal. Centres of human transportation that are connected by trade to a wide range of other locations (‘transport hubs’) may be important catalysts of the rate at which new populations of an invader are established. 2. We developed a spatially explicit stochastic model to simulate the spread of a hypothetical marine invader by hull fouling. The model was based on classic ‘Susceptible–Infected–Resistant’ models used in medical epidemiology. It was parameterized using empirical data on the colonization of vessel hulls by fouling organisms, and on maintenance and travel patterns of ~1300 domestic and international yachts around New Zealand. Thirty-six marinas were grouped into three categories that represented a gradient in the number of other transport nodes each marina was ‘connected’ to and the frequencies of yacht movements between them. Invasions were seeded in three locations from each category. Simulations were run over 10 years to determine differences in the trajectory of invasions originating from busy and less frequented transport nodes. 3. Busy ‘hub’ locations were 75% more likely to become infected by an invader than quieter locations. Infection of hub nodes occurred at an earlier average stage in the invasion sequence. This occurred irrespective of whether the initial source of the invasion was associated with low or high traffic volume and connectivity. 4. Biotic invasions originating from hub locations did not consistently result in faster spread, or a larger number of secondary infestations. However, the rate of spread from hubs was less variable than from quieter nodes and was less often preceded by a prolonged lag period. 5. Synthesis and applications. Rapid spread of invasive organisms can occur from busy and from seemingly unimportant transport nodes. Busy locations were consistently more likely to become infested by an invader and to accelerate spread to secondary locations faster. Busy transport hubs should be considered a priority for the allocation of preventative and management efforts, such as regular baseline or target surveys and the development of incursion response plans that minimize the risk of spread within the transport network. [ABSTRACT FROM AUTHOR]

The International Council for the Exploration of the Sea (ICES) noted the risks associated with uncontrolled species introductions and transfers more than 40 years ago and launched two working groups to address the issue, i.e. the ICES Working Group on Introductions and Transfers of Marine Organisms (WGITMO) to deal with the movement of non-indigenous species for e.g. aquaculture purposes and the ICES/IOC/IMO Working Group on Ballast and Other Ship Vectors which focuses on species movements with ships. Both groups are actively working until today and the key achievements of the groups are outlined. [Copyright &y& Elsevier]

Preventing the introduction of nonindigenous species (NIS) is the most efficient way to avoid the costs and impacts of biological invasions. The transport of fouling species on ship hulls is an important vector for the introduction of marine NIS. We use quantitative risk screening techniques to develop a predictive tool of the abundance and variety of organisms being transported by ocean-going yachts. We developed and calibrated an ordinal rank scale of the abundance of fouling assemblages on the hulls of international yacht hulls arriving in New Zealand. Fouling ranks were allocated to 783 international yachts that arrived in New Zealand between 2002 and 2004. Classification tree analysis was used to identify relationships between the fouling ranks and predictor variables that described the maintenance and travel history of the yachts. The fouling ranks provided reliable indications of the actual abundance and variety of fouling assemblages on the yachts and identified most (60%) yachts that had fouling on their hulls. However, classification tree models explained comparatively little of the variation in the distribution of fouling ranks (22.1%), had high misclassification rates (∼43%), and low predictive power. In agreement with other studies, the best model selected the age of the toxic antifouling paint on yacht hulls as the principal risk factor for hull fouling. Our study shows that the transport probability of fouling organisms is the result of a complex suite of interacting factors and that large sample sizes will be needed for calibration of robust risk models. [ABSTRACT FROM AUTHOR]

The presence and impacts of non-indigenous species (NIS) in marine areas of high conservation or World Heritage significance have rarely been examined. Case studies worldwide suggest that the potential exists for the introduction of NIS to significantly impact conservation values in regions conserved for the uniqueness and diversity of native assemblages. In this study, a preliminary investigation was conducted to provide information essential for managing marine introductions in the Shark Bay World Heritage Property. A focused fouling plate survey sampled a total of 112 encrusting taxa, of which 10 (11.2%) were classified as introduced and 10 others as cryptogenic. Eight introduced bryozoans:Aetea anguina(Linnaeus, 1758),Bugula neritina(Linnaeus, 1758),Bugula stoloniferaRyland, 1960,Conopeum seurati(Canu, 1928),Savignyella lafontii(Audouin, 1826),Schizoporella errata(Waters, 1878),Watersipora subtorquata(d’Orbigny, 1842) andZoobotryon verticellatumdella Chiaje, 1828; one tunicate,Styela plicataLesueur, 1823; and an introduced hydroid,Obelia dichotoma(Linnaeus, 1758) were frequent, and in some cases dominant, components of encrusting communities. Of the 20 most frequently occurring species detected in the Bay, four were introduced and of the 20 species with highest average percent cover per plate, six were introduced. At one site, space occupation by NIS averaged 71.6% ± 7.4 of plate live cover. Space occupation by an individual NIS was as high as 62.4% of plate area (mean 7.82% ± 1.8). NIS were detected at sites lacking commercial traffic and ballast water discharge and isolated by distance and physical environment, suggesting that hull fouling of recreational craft may be the most important vector in the region. Seventy-five percent of NIS detected in Shark Bay are established in Australian ports to the south of Shark Bay, while 33% are established to the north, tentatively implicating temperate affinity NIS and the movement of vessels from Australian ports south of Shark Bay as a greater risk to the region. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the facilitation at an earlier stage in the invasion process of interactions between nonindigenous species (NIS) by human vectors. It offers a comparison of the recruitment of fouling organisms to mimic bryozoan Watersipora subtorquata colonies of three different sizes. Also revealed is the increase of invasion success by positive interactions between NIS that enhance the delivery of propagules by human transport vectors.

Eradication of invasive species is difficult in the marine environment, and there have only been a few successes. We report the successful eradication of the invasive seaweed Undaria pinnatifida from a sunken trawler in the Chatham Islands, New Zealand. New heat-treatment methods were developed as the most cost effective and environmentally acceptable option to kill Undaria. Monitoring of the trawler for three years after it sank found no Undaria after the vessel was treated. Key factors in the success of the eradication programme included: early detection, a rapid response, pre-existing knowledge of Undaria, an adaptive management approach, targeting of multiple life history stages, and the cooperation of the vessel''s insurer. [Copyright &y& Elsevier]