Transoceanic Vessels Research Articles

Notes on the Spreading of Penaeus aztecus Ives 1891 (Decapoda, Penaeidae) in the Mediterranean Sea and on Its Repeated Misidentifications in the Region.

The shrimp Penaeus aztecus, native to the western Atlantic, was first reported in the eastern Mediterranean Sea in 2010. New records, from different Mediterranean localities, multiplied in the following years. The accurate search of the literature on non-indigenous species discovered it was misidentified more than once as another alien shrimp, P. semisulcatus, native to the Indo-Pacific region, with the result that its earlier presence in the Black Sea went unnoticed. Morphological characteristics allowing the identification of these two species, the autochthonous P. kerathurus and two other alien Penaeus species present in the Mediterranean, are reprised. The present distribution of P. aztecus based on literature records and surveys carried out in the northern and central Adriatic between 2016 and 2021 is mapped. The unintentional transport of larvae carried in ballast water by transoceanic vessels departing from the U.S. East Coast is suggested as the most probable introduction pathway. The significance of the correct identification of non-indigenous species, a "Descriptor" adopted in the Marine Strategy Framework Directive for determining the good environmental status of marine waters in the European States, is emphasized.

The future of species invasions in the Great Lakes-St. Lawrence River basin

No other freshwater system contains as many non-native species or has been invaded as frequently as the Great Lakes-St. Lawrence River basin. Over 180 non-native species have become established in the basin within the past two centuries. Collectively, these invasions have altered biodiversity, habitat structure, productivity, water quality, contaminant cycling and ecosystem services. The composition and rate of discovery of invaders are correlated with changes in dominant vectors, such as transoceanic shipping. We review the invasion history of the basin and identify future invasion threats by considering trends and potential scenarios in changing vectors and pathways. Whereas most non-native species discovered since the opening of the St. Lawrence Seaway in 1959 were attributable to ballast water discharge from transoceanic vessels, recent regulations have apparently reduced the threat of this vector. Nevertheless, non-native species may continue to be introduced through poorly-regulated vectors, particularly those associated with trade in live organisms. The spread and impact of current and future invaders are expected to be exacerbated by interactions with other anthropogenic stressors that are increasing in frequency and spatial extent. Most notably, the continued warming of surface waters of the Great Lakes basin will lift thermal barriers to invasions by warm-water taxa. Contrary to any perception that the “worst is over” (i.e. most harmful invasions have already occurred), the basin remains vulnerable to further ecological and economic disruptions from non-native species.

Domestic ships as a potential pathway of nonindigenous species from the Saint Lawrence River to the Great Lakes

Ballast water moved by transoceanic vessels has been recognized globally as a predominant vector for the introduction of aquatic nonindigenous species (NIS). In contrast, domestic ships operating within confined geographic areas have been viewed as low risk for invasions, and are exempt from regulation in consequence. We examined if the St. Lawrence River could serve as a source of NIS for the Laurentian Great Lakes by surveying ballast water carried by domestic vessels and comparing biological composition in predominant St. Lawrence River-Great Lakes port-pairs in order to determine the likelihood that NIS could be transported to, and survive in, the Great Lakes. Thirteen potential invaders were sampled from ballast water, while 26 taxa sampled from St. Lawrence River ports are not reported from the Great Lakes. The majority of NIS recorded in samples are marine species with low potential for survival in the Great Lakes, however two euryhaline species (copepod Oithona similis, and amphipod Gammarus palustris) and two taxa reported from brackish waters (copepod Microsetella norvegica and decapod Cancer irroratus) may pose a risk for invasion. In addition, four marine NIS were collected in freshwater samples indicating that at least a subset of marine species have potential as new invaders to the Great Lakes. Based on results from this study, the ports of Montreal, Sorel, Tracy and Trois Rivières appear to pose the highest risk for new ballast-mediated NIS from the St. Lawrence River to the Great Lakes.

Role of domestic shipping in the introduction or secondary spread of nonindigenous species: biological invasions within the Laurentian Great Lakes

Summary The most effective way to manage invasive species is to prevent their introduction via vector regulation. While progress has been made in the management of transoceanic ballast water, domestic vessels operating within smaller geographic regions such as the Laurentian Great Lakes, Mediterranean Sea, North Sea or Baltic Sea are often exempt from regulations. We randomly surveyed unmanaged ballast water moved by domestic vessels within the Laurentian Great Lakes and compared the results with that of exchanged ballast water from transoceanic vessels to assess invasion risk of zooplankton transported by these two types of vessels. Total abundance and species richness were significantly different between the two vessel types with mean abundance being two magnitudes greater, and species richness being threefold higher in domestic vessels compared with transoceanic vessels. Abundance of restricted taxa – cumulatively the Great Lakes' indigenous and nonindigenous species (NIS) which do not occur in all five lakes – was also significantly higher in domestic vessels (mean densities were 24 170 and 3421 individuals per m3 for domestic and transoceanic vessels, respectively), whereas the abundance of NIS did not differ between vessels (median densities of 2015 and 850 individuals per m3, respectively). We documented 89 species transported by domestic vessels of which 31 had restricted distribution and eight were NIS. While most NIS were already established in all five lakes, Cercopagis pengoi, a NIS of global concern, and Nitokra hibernica have not been identified from Lake Superior, and both were sampled from ballast water destined for discharge in Lake Superior. Beside the risk of spread of NIS between lakes, domestic shipping can act as a vector for homogenization of indigenous taxa, with at least 21 native species (99 events) being moved outside their historical distribution. Synthesis and applications. Our study indicates that management of invasive species should consider ecological, not geographical or political boundaries. Domestic vessels operating within a limited geographic region have high potential to introduce or spread species with restricted distribution, demonstrating importance of intraregional ballast water management. Results presented here should interest policy makers and environmental managers who seek to reduce invasion risk.

Efficacy of NaCl brine for treatment of ballast water against freshwater invasions

Currently, all transoceanic vessels entering the Great Lakes must perform ballast water exchange or saltwater flushing, procedures designed to reduce the risk of new biological invasions from ballast water. Vessels not in compliance with these regulations presently have limited, often costly, and/or time-consuming alternatives available. Treatment with sodium chloride brine at an initial concentration of 230‰ has been proposed as an emergency ballast water management option and is examined here. Six shipboard trials were conducted under operational conditions to determine the efficacy of brine ballast water treatment. Trials were conducted on three vessels with full ballast tanks and on three vessels with only residual ballast water. Brine distribution in tanks was adequate, noting that vessel movement was essential to ensure mixing into ballast water or ballast residuals. Once mixing has occurred, approximately 25hour exposure to 45‰ brine or 1 hour exposure to 115‰ brine is required to effectively exterminate freshwater zooplankton. Brine appears to be a cost-effective and relatively safe procedure that could be implemented immediately for emergency treatment of non-compliant ballast water to reduce risk of new invasions in the Great Lakes.

Hull fouling as an invasion vector: can simple models explain a complex problem?

Summary 1. The most effective way to manage nonindigenous species and their impacts is to prevent their introduction via vector regulation. While ships’ ballast water is very well studied and this vector is actively managed, hull fouling has received far less attention and regulations are only now being considered despite its importance for introductions to coastal, marine systems. 2. We conducted comprehensive in situ sampling and video recording of hulls of 40 transoceanic vessels to assess propagule and colonization pressure in Vancouver and Halifax, dominant coastal ports in Canada. Concomitant sampling was conducted of harbour fouling communities to compare hull and port communities as part of a vector risk assessment. 3. Although this vector has been operational for a long time, hull and harbour communities were highly divergent, with mean Sørensen’s similarity values of 0·03 in Halifax and 0·01 in Vancouver, suggesting invasion risk is high. Propagule pressure (up to 600 000 ind. ship−1) and colonization pressure (up to 156 species ship−1) were high and varied significantly between ports, with Vancouver receiving much higher abundances and diversity of potential invaders. The higher risk of fouling introductions in Vancouver is consistent with historical patterns of successful hull fouling invasions. 4. The extent of hull fouling was modelled using ship history predictors. Propagule pressure increased with time spent in previous ports‐of‐call and time since last application of antifouling paint, whereas colonization pressure increased with time since last painting and with the number of regions visited by the ship. Both propagule and colonization pressure were negatively related to the time spent at sea and the latitude of ports visited. 5. Synthesis and applications. A major challenge for applied invasion ecology is the effective management of introduction vectors. We found that hull fouling has a strong potential for introduction of many species to coastal marine habitats and that management should be considered. Simple variables related to the vessels’ hull husbandry, voyage, and sailing patterns may be used to predict and manage hull fouling intensity. The results presented here should interest policy makers and environmental managers who seek to reduce invasion risk, and ship owners seeking to optimize fuel efficiency.

Brine-induced mortality of non-indigenous invertebrates in residual ballast water

All transoceanic vessels entering the Great Lakes are required to manage ballast water and ballast tank residuals with ballast water exchange and tank flushing, respectively. While these management procedures effectively reduce the density and richness of biota in ballast waters and thereby reduce the risk of transferring non-indigenous species, some ships are unable to uniformly manage all tanks. Laboratory experiments were conducted to evaluate sodium chloride brine as an emergency treatment for ballast tanks with non-compliant residuals. Invertebrate communities collected from i) Detroit River, ii) exchanged ballast tanks arriving in the Great Lakes, and iii) North Sea ports, were exposed to a range of brine concentrations (15–115‰) until complete mortality was reached. Results indicate that a 1-h exposure to 115‰ brine is a broadly effective treatment (>99.9% mortality) regardless of treatment temperature, taxonomic group, or species’ source habitat salinity. A median of 0.00% (range 0.00–5.33) of individuals are expected to survive treatment and the expected number of viable individuals released after treatment is within Canadian and proposed international discharge standards. Before implementation, validation with ship-scale trials is recommended.

Is vessel hull fouling an invasion threat to the Great Lakes?

AbstractAim 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 asGammarus tigrinusandDreissena 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.

Phylogeography of the widespread marine invader Microcosmus squamiger (Ascidiacea) reveals high genetic diversity of introduced populations and non‐independent colonizations

ABSTRACTThe spread of non‐indigenous species into new marine habitats represents an increasing threat to global diversity. Genetic techniques provide basic understanding of the invasion processes. The ascidian Microcosmus squamiger is considered to be native to Australia, having been spread worldwide via transoceanic vessels. It has successfully invaded artificial and natural habitats where it has become a pest. We studied phylogeography and genetic structure of 12 M. squamiger populations, including samples from its native range (Australia) and introduced populations from the Indian, Pacific, and Atlantic oceans, as well as the Mediterranean Sea. We amplified 574 bp of the mitochondrial COI gene in 258 individuals and found a total of 52 haplotypes. A haplotype tree revealed two main groups of haplotypes. The relative frequency of each group of haplotypes, multidimensional scaling, and analysis of molecular variance showed important differences between the western Australia localities and the remaining ones (eastern Australia and introduced populations). Furthermore, we found that the colonization of the different areas by M. squamiger has not occurred independently, as many introduced populations shared some low frequency alleles. A nested clade analysis showed a global pattern of restricted gene flow with isolation by distance, although we found episodes of long‐distance dispersal in some clades. A contiguous range expansion was detected between Australian populations. We conclude that M. squamiger is native to Australia and has most likely expanded its range of distribution sequentially through worldwide shipping, especially from the harbours of the more populated eastern Australia. In introduced populations, we found a high genetic diversity which suggests enhanced invasive potential. Consequently, there is a need to control this species, as it outcompetes local biota and is an economic threat.

Efficacy of open‐ocean ballast water exchange as a means of preventing invertebrate invasions between freshwater ports

Ballast water is a major vector of nonindigenous species invasion globally. Mandatory ballast water exchange (BWE) was implemented for vessels carrying ballast water into the Great Lakes in 1993. Despite the implementation of this policy, few data are available on its effectiveness, and invasions have continued to be reported in the Great Lakes. In this study, we conducted experiments to assess the efficacy of BWE on six operational transoceanic vessels traveling from the Great Lakes to European ports. Each vessel had paired ballast tanks, one of which was designated as a control that remained filled with Great Lakes water, while the other was exchanged with mid‐ocean water. Community composition was assessed immediately after tanks were filled and again prior to water discharge in European ports. BWE was verified by ship records and, in two cases, by in situ water quality sensors. BWE was highly effective (>99% loss) for reducing concentrations of freshwater zooplankton. Live sentinel amphipods and oligochaetes deployed in incubator chambers sustained nearly universal mortality in tanks that experienced BWE, but not in unexchanged tanks. Finally, BWE reduced in situ recruitment of zooplankton from diapausing eggs present in ballast sediments in additional incubator chambers deployed in these tanks. Collectively, these studies support the contention that BWE by transoceanic vessels traveling between freshwater ports results in ballast water that would exceed proposed International Maritime Organization (2004) ballast water performance standards if these standards were applied to freshwater species only. Thus, BWE provides strong protection to freshwater ecosystems against invasions by both pelagic and benthic freshwater species.

Sediments in ships: Biota as biological contaminants

Global ports are hubs for industrial activities and trade. In consequence, sediments and water in these areas are often contaminated by an array of chemicals. Sediments also harbour both living, active stages and various diapausing or resting stages of biota. International shipping activities move sediments containing these biotic stages around the world, possibly resulting in biological contamination of port areas. In this study we assess active and resting stages of invertebrates contained in ballast sediment of transoceanic vessels operating on the North American Great Lakes to determine if ballast sediments could serve as a vector of nonindigenous species. A cumulative total of 160 species were identified, including 22 freshwater species not recorded from the Great Lakes! basin. Hatch rates of resting stages are affected by thermal conditions, thereby affecting invasion success. Total abundance and species diversity of freshwater invertebrate animals hatched from resting stages were negatively related to salinity of residual water in ballast tanks from which the sediments were obtained, suggesting that ballasting a shallow lens of saltwater may provide some degree of risk reduction from freshwater species invasions.

Can sodium hypochlorite reduce the risk of species introductions from diapausing invertebrate eggs in non-ballasted ships?

Many transoceanic vessels enter the Great Lakes carrying residual ballast water and sediment that harbours live animals and diapausing eggs. In this study, we examine the potential for sodium hypochlorite (NaOCl) to reduce the risk of species introductions from diapausing invertebrate eggs in residual ballast sediment. We collected sediment from three transoceanic vessels and from Lake Erie and exposed them to NaOCl concentrations between 0 and 10,000 mg/L for 24 h. Hatching success was reduced by >89% in all four experiments at 1000 mg/L relative to unexposed controls. Fewer species hatched at high than at low NaOCl concentrations. Based on an average residual ballast of 46.8 tonnes, the volume of NaOCl required to treat inbound vessels is 374 L. Impacts of NaOCl use could be minimized by neutralization of treated residuals with sodium bisulfite. Further research is needed, however, to evaluate the effect of NaOCl on ballast tank corrosion.

Salinity tolerance of diapausing eggs of freshwater zooplankton

Summary1. Many freshwater zooplankton produce diapausing eggs capable of withstanding periods of adverse environmental conditions, such as anoxia, drought and extreme temperature. These eggs may also allow oligostenohaline species to survive increased salinity during periods of tidal flux or evaporation, and here we test the ability of diapause eggs to withstand such conditions.2. Salinity tolerance may also enable organisms to invade new environments. The increased rate of introduction of non‐indigenous species to the Laurentian Great Lakes since 1989, when ballast water exchange regulations (to replace fresh/brackish water at sea with full seawater) were first implemented for transoceanic vessels, has stimulated studies that explore mechanisms of introduction, other than of active animals, in ballast water. One hypothesis proposes that freshwater organisms transported in ballast tanks as diapausing eggs may be partially responsible for the increased rate of species introduction, as these eggs may tolerate a wide array of adverse environmental conditions, including exposure to saline water.3. We collected ballast sediments from transoceanic vessels entering the Great Lakes, isolated diapausing eggs of three species (Bosmina liederi, Daphnia longiremis and Brachionus calyciflorus), and measured the effect of salinity on hatching rate. In general, exposure to salinity significantly reduced the hatching rate of diapausing eggs. However, as non‐indigenous species can establish from a small founding population, it is unclear whether salinity exposure will be effective as a management tool.

Comparative Efficacy of Potential Chemical Disinfectants for Treating Unballasted Vessels

The release of ballast water from transoceanic vessels is a major vector for the introduction of nonindigenous species into the Laurentian Great Lakes. This study assessed the effectiveness of treating unballasted transoceanic vessels using three different biocides: glutaraldehyde plus a surfactant adjuvant (Disinfekt 1000 ®), sodium hypochlorite (NaOCl), and SeaKleen™ (menadione and menadione metabisulfite 2:8). Efficacy against several classes of aquatic organisms was evaluated using 24 h acute toxicity experiments and 11 day ballast tank simulation experiments. The results indicate substantial, compound-specific variations in organism sensitivity. For water-only exposures, NaOCl and SeaKleen™ were most effective: NaOCl had the lowest LC 90 (90% lethal concentration value) for the oligochaete Lumbriculus variegatus (1.0 mg L −1), while SeaKleen™ had the lowest LC 90 for the amphipod Hyalella azteca (2.5 mg L −1). Sediments profoundly affected efficacy, particularly for NaOCl: At a 1:4 sediment-water ratio, the estimated LC 90 for L. variegatus was > 2,000 mg L −1. Sediment quality also impacted efficacy: Sediments with higher organic carbon content typically required greater biocide concentrations to achieve comparable toxicity. Efficacy was further evaluated with 11 day bioassays using sediments from unballasted vessels. Results indicated that NaOCl and Disinfekt 1000 ® were more effective than predicted based on small scale sediment-water exposures. Overall, the data suggest that although NaOCl may be effective under water-only conditions, the higher concentrations required in the presence of sediments may cause corrosion problems for ballast tanks. Because of this, less reactive, non-oxidizing biocides such as SeaKleen™ and Disinfekt 1000 ® may be better candidates for treating sedimented tanks.

Viability of invertebrate diapausing eggs collected from residual ballast sediment

Natural or anthropogenic movement of sediments may be an important vector for the dispersal of invertebrate resting stages between water bodies. Here we record the presence of invertebrate diapausing eggs in residual sediments from transoceanic vessels and explore whether these may pose an invasion risk. Viability of diapausing eggs was explored under light and dark conditions using sediment collected from eleven tanks on nine vessels operating on the Great Lakes. Seventeen cladoceran, copepod, and rotifer taxa were identified. Four of the species hatched have not yet been reported as established in the Great Lakes. Egg viability for individual species varied from 0% to 92%. Exposure to saline water may impact egg viability of some freshwater species. Generally, the proportion of eggs hatched in light and dark treatments did not differ significantly, indicating that light was not required to terminate diapause. As a result, eggs could potentially hatch in dark ballast tanks when immersed in freshwater loaded as ballast during operation on the Great Lakes. Viability of diapausing eggs differed among ballast tanks on a single vessel, indicating that tanks with independent ballast histories have different invasion risks. While additional work is needed to quantify risk, results from this study indicate that vessels entering the Great Lakes with only residual ballast are a potential vector for the introduction of new nonindigenous species during multiport operations.

Assessing the Potential Efficacy of Glutaraldehyde for Biocide Treatment of Un-ballasted Transoceanic Vessels

Treating the ballast water of oceanic vessels with a biocide is one potential management strategy to reduce the number of nonindigenous species released into the Laurentian Great Lakes from NOBOB ( no ballast on board) vessels. To evaluate biocide effectiveness, glutaraldehyde, a five-carbon dialdehyde widely used for its antimicrobial properties, was investigated. Biocide effectiveness was assessed for various organisms using 24 h acute toxicity bioassays in water-only and water-sediment environments. Acute studies indicate a 24 h LC 90 value of 100 mg glutaraldehyde L –1 or less for most of the freshwater organisms tested. The main exception was the freshwater amphipod, Hyalella azteca, which was much more resistant to glutaraldehyde (24 h LC 90 = 550 mg glutaraldehyde L −1; 95% CI: 476–681). Biocide efficacy was also evaluated in water-sediment exposures. The presence of a test sediment (3% organic carbon) greatly increased lethal concentration estimates for the oligochaete Lumbriculus variegatus, but not for H. azteca: The 24 h LC 90 for L. variegatus varied depending on the water-sediment ratio, and ranged from 61 mg glutaraldehyde L −1 (95% CI 52–78) for an 8:1 water-sediment ratio to 356 mg glutaraldehyde L −1 (95% CI 322–423) for a 2:1 water-sediment ratio. This indicates that the amount of sediments present in NOBOB vessels may have a significant impact on biocide efficacy. Experiments using material from actual NOBOB vessels generally corroborated data from the water-sediment experiments and suggest a potential treatment concentration of approximately 500 mg glutaraldehyde L −1 for short exposure periods (e.g., 24 h).

Another exotic mollusc in the Laurentian Great Lakes: the New Zealand native Potamopyrgus antipodarum (Gray 1843) (Gastropoda, Hydrobiidae)

In 1991, the hydrobiid snail Potamopyrgus antipodarum (Gray 1843), native to New Zealand, was found 1 km offshore Wilson, New York, in Lake Ontario. This is the first known occurrence of the snail in eastern North America. Densities of P. antipodarum have increased since its discovery, and the snail is expected to spread quickly throughout the Great Lakes area. The biofouling potential of P. antipodarum is probably low; however, its most serious threat may be resource competition with native molluscs. This species was probably introduced in ballast water from transoceanic vessels, thus increasing the list of nonindigenous aquatic organisms introduced into the Great Lakes since the 1800s to 140 different organisms. The risk of other species invasions into the Great Lakes is still possible, despite the now mandatory ballast water regulations.

Multichannel VHF for marine communications

This paper is a discussion of a remotely controlled VHF Marine Radiotelephone designed for installation on boats which operate along the coasts, on inland rivers and lakes, as well as transoceanic vessels. This equipment provides simultaneous monitoring on three of the twenty-nine channels presently available. Basic design and construction are discussed.