Open-ocean Ballast Water Exchange Research Articles

Efficacy of open-ocean ballast water exchange: a review

Efficacy of open-ocean ballast water exchange: a review

Assessing introduction risk using species' rank-abundance distributions.

Mixed-species assemblages are often unintentionally introduced into new ecosystems. Analysing how assemblage structure varies during transport may provide insights into how introduction risk changes before propagules are released. Characterization of introduction risk is typically based on assessments of colonization pressure (CP, the number of species transported) and total propagule pressure (total PP, the total abundance of propagules released) associated with an invasion vector. Generally, invasion potential following introduction increases with greater CP or total PP. Here, we extend these assessments using rank-abundance distributions to examine how CP : total PP relationships change temporally in ballast water of ocean-going ships. Rank-abundance distributions and CP : total PP patterns varied widely between trans-Atlantic and trans-Pacific voyages, with the latter appearing to pose a much lower risk than the former. Responses also differed by taxonomic group, with invertebrates experiencing losses mainly in total PP, while diatoms and dinoflagellates sustained losses mainly in CP. In certain cases, open-ocean ballast water exchange appeared to increase introduction risk by uptake of new species or supplementation of existing ones. Our study demonstrates that rank-abundance distributions provide new insights into the utility of CP and PP in characterizing introduction risk.

Net efficacy of open ocean ballast water exchange on plankton communities

We evaluated the efficacy of two ballast water exchange (BWE) methods during two transoceanic voyages of a bulk carrier in September 1999 and October 2000 between Rotterdam (The Netherlands) and Sept-Iles (Canada). The experimental design accounted for the uptake of new species during exchanges by considering only those taxa observed prior to BWE (initial taxa). To account for natural decreases due to mortality in the tanks, communities in exchanged ballast tanks were compared with those in control tanks, thus allowing the ‘net BWE efficacy’ of the procedures to be determined. The efficacy of the removal of organisms varied among BWE methods, plankton communities (microplankton and zooplankton) and taxonomic groups. BWE efficacy was greater for zooplankton (72–90%) than microplankton (49–80%). When the fairly high natural mortality observed in control tanks was considered in the calculation of BWE efficacy (net BWE efficacy), much lower efficacy was observed (microplankton: 29–40%; zooplankton: 23–54%). The 300% flow-through method (FT) is the most effective BWE method (net efficacy) for removing initial microplankton taxa (1999 and 2000), whereas the FT was either similarly (1999) or less than (2000) effective compared with the procedure normally carried out on board this vessel (NORM method) for the zooplankton community. However, BWE was more efficient in removing microplankton than zooplankton in 1999 while the opposite pattern occurred in 2000. The seasonal timing of voyages and the BWE site influenced the density and composition of species introduced to tanks during BWE.

Diapausing zooplankton eggs remain viable despite exposure to open-ocean ballast water exchange: evidence from in situ exposure experiments

To reduce the transfer of nonindigenous species, regulations require transoceanic ships to exchange ballast with ocean water before discharging into the Great Lakes. Although ballast water exchange (BWE) is effective for live freshwater animals, laboratory experiments provide mixed results with regards to its impact on diapausing zooplankton eggs. We conducted an in situ test of the effectiveness of BWE for treating diapausing eggs in ballast sediments. Incubation chambers containing ballast sediment were placed in ballast tanks of cargo vessels transiting from North America to Europe. Each vessel had paired ballast tanks, one of which remained filled with Great Lakes water (control), while the second was exchanged with mid-ocean water. Laboratory viability tests were then conducted to compare viability of eggs recovered from sediments placed in both treatments, as well as identical sediments that remained at the laboratory in cold storage. No significant differences in egg viability were detected between treatments, but more species hatched from sediment that remained in cold storage. Results indicate that physical conditions in ballast tanks may affect egg viability, but saltwater exposure does not eliminate the risk of species introductions via diapausing eggs. Strategies that minimize sediment accumulation in ballast tanks can reduce the risk of species introductions via diapausing eggs.

Concentrated sodium chloride brine solutions as an additional treatment for preventing the introduction of nonindigenous species in the ballast tanks of ships declaring no ballast on board

Currently, seawater flushing is the only management strategy for reducing the number of viable organisms in residual sediments and water of ballast tanks of vessels declaring no ballast on board (NOBOB) that traffic ports of the eastern United States. Previously, we identified several species of freshwater and brackish-water peracarid crustaceans able to survive the osmotic shock that occurs during open-ocean ballast water exchange and, potentially, to disperse over long distances via ballasted ships and NOBOB vessels. We tested the efficacy of concentrated sodium chloride brine solutions as an additional treatment for eradicating the halotolerant taxa often present in the ballast tanks of NOBOB ships. The lowest brine treatments (30 ppt for 1 h) caused 100% mortality in several species of cladocerans and copepods collected from oligohaline habitats. Several brackish-water peracarid crustaceans, however, including some that can survive in freshwater as well, required higher brine concentrations and longer exposure durations (45-60 ppt for 3-24 h). The most resilient animals were widely introduced peracarid crustaceans that generally prefer mesohaline habitats but do not tolerate freshwater (required brine treatments of 60-110 ppt for 3-24 h). Brine treatments (30 ppt) also required less time to cause 100% mortality for eight taxa compared with treatments using 34 ppt seawater. Based on these experiments and published data, we present treatment strategies for the ballast tank biota often associated with NOBOB vessels entering the Great Lakes region. We estimate the lethal dosage of brine for 95% of the species in our experiments to be 110 ppt (95% confidence interval, 85-192 ppt) when the exposure time is 1 h and 60 ppt (95% confidence interval, 48-98 ppt) when the exposure duration is 6 h or longer.

Effect of osmotic shock as a management strategy to reduce transfers of non-indigenous species among low-salinity ports by ships

Open-ocean ballast-water exchange (BWE) is currently the most common treatment used to reduce the ballast transfer of organisms and the subsequent risk of invasions among coastal ecosystems. Freshwater or estuarine organisms remaining after BWE often experience high mortality, due to osmotic shock caused by high-salinity exposure. We conducted 70 salinity tolerance experiments on 54 different taxa to measure mortality rates of freshwater and estuarine organisms after exposure to oceanic seawater (34 psu), simulating both flow-through (F-T) and empty-refill (E-R) BWE methods. We focused especially on larval and adult crustaceans from freshwater and mesohaline habitats adjacent to ports of the Baltic Sea, North Sea, Great Lakes, Chesapeake Bay, and San Francisco Bay. Animals from oligohaline habitats (0-2 psu) experienced the highest mortality: all individuals died in 82% of the F-T treatments and 88% of the E-R treatments. The effectiveness of both treatment types decreased with animals from low-salinity (2-5 psu, 100% mortality in 27% of F-T and 46% of E-R treatments) and mesohaline habitats (5-18 psu, 100% mortality in 40% of F-T and 52% of E-R treatments). In 43% of cases among all salinity categories, empty-refill treatments required less exposure time to cause significant mortality than flow-through treatments. Invertebrates that exhibited significant survivorship were most often peracarid crustaceans including widely introduced species of mysid shrimps and amphipods. Although salinity shock does not completely prevent the transfer of all low-salinity biota, BWE provides a useful management tool to reduce species transfers, especially considering the combined effects of removal and mortality.

Trans-Pacific shipboard trials on planktonic communities as indicators of open ocean ballast water exchange

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 350:41-54 (2007) - DOI: https://doi.org/10.3354/meps07016 Trans-Pacific shipboard trials on planktonic communities as indicators of open ocean ballast water exchange Michael D. Taylor1,*, Lincoln M. MacKenzie1, Timothy J. Dodgshun1, Grant A. Hopkins1, Eykolina J. de Zwart1, Carlton D. Hunt2 1Cawthron Institute, 98 Halifax Street East, Private Bag 2, Nelson 7042, New Zealand 2 Battelle, 397 Washington Street, Duxbury, Massachusetts 02332, USA *Email: mike.taylor@cawthron.org.nz ABSTRACT: A trans-Pacific voyage from Japan to New Zealand via Singapore was used to assess planktonic (and sediment-dwelling) communities as indicators of open ocean ballast water exchange (BWE). The research was part of a larger project to develop methods for verifying whether international shipping has complied with mandatory controls and voluntary BWE guidelines. The dilution efficiency of exchanges was compared with changes in the composition and abundance of ballast tank phyto- and zooplankton taxa. Changes in the planktonic communities were measured by sampling the source port, the ballast water at the source and recipient ports and immediately before and after BWE, and the open ocean water during exchanges. Although exchanges appeared relatively effective at reducing the abundance (90 to 100%) of phyto- and zooplankton indicator taxa (i.e. taxa in the ballast water uploaded from the source port that were not present in open ocean samples or were present at <0.001 the original concentration), such reductions must be considered in the light of variation in survivorship in the control tank. Relatively high rates of mortality were associated with a rapid warming (i.e. 14.0 to 27.8°C) of the exchanged and control ballast tanks as the vessel entered the tropics. The rapid decline in the abundance of indicator taxa after BWE contrasted with a less effective reduction (i.e. 30.3 and 25.0% for the first and second exchanges, respectively) in the total number of phyto- and zooplankton taxa. Management controls and guidelines should place greater emphasis on whether the water uploaded during BWE is sufficiently oceanic to minimise the risk of uploading harmful coastal organisms. KEY WORDS: Ballast water exchange · Tracer dye · Phytoplankton · Zooplankton · Sediment-dwelling species · Biological indicators · Open ocean · Trans-Pacific voyage Full text in pdf format PreviousNextCite this article as: Taylor MD, MacKenzie LM, Dodgshun TJ, Hopkins GA, Zwart EJd, Hunt CD (2007) Trans-Pacific shipboard trials on planktonic communities as indicators of open ocean ballast water exchange. Mar Ecol Prog Ser 350:41-54. https://doi.org/10.3354/meps07016 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 350. Online publication date: November 22, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

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 (&gt;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.

An ambient tax approach to invasive species

Invasive species have become an issue of increasing concern in recent years. Invasive species are species that are not native to an area but are imported either intentionally or unintentionally and become established. A primary pathway for introduction is the ballast water of ships. Although not all imported species become invasive, those that do cause extensive damage to ecosystems and have been blamed for the endangerment of numerous native species. In many cases, release of non-native species can be prevented, either through open-ocean ballast water exchange, retention of ballast water, or other biosecurity measures. However, policies designed to encourage such actions face several specific challenges. The difficulty of linking an invasion to a specific vessel and of monitoring individual vessels' care makes using standard environmental liability plans difficult if not impossible. In this paper, we present an alternative policy option, that of an ambient tax. Building on the work of Segerson [Segerson, Kathleen, 1988. Uncertainty and incentives for nonpoint pollution control. Journal of Environmental Economics and Management, 15: 87–98.], we show that an ambient tax can ensure socially optimal behavior in both the short-run and the long-run with minimal vessel specific information.

Optical signatures of seawater and potential use for verification of mid-ocean ballast water exchange

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 331:35-47 (2007) - doi:10.3354/meps331035 Optical signatures of seawater and potential use for verification of mid-ocean ballast water exchange Carlton D. Hunt1,*, Deborah Tanis1, Elizabeth Bruce1, Michael Taylor2 1Battelle, 397 Washington Street, Duxbury, Massachusetts 02332, USA 2Cawthron Institute, Private Bag 2, Nelson, New Zealand *Email: huntc@battelle.org ABSTRACT: Mandatory requirements for exchange of ships’ ballast water in the open ocean require an effective means of verifying that open ocean exchange has occurred. This study demonstrates that UV fluorescence of chromophoric organic matter in seawater has great potential to verify open ocean ballast water exchange. Ballast water samples, obtained for excitation-emission spectral analysis during 2 flow-through ballast water exchange events in the trans-Pacific voyage of a chemical carrier, establish a clear difference between the UV fluorescence characteristics of ballast water before and after mid-ocean exchange. The exchange of water in mid-ocean shifted the fluorescence signatures of ballast water from those typical of the coastal water at the donor ports to those of the exchanged mid-ocean water. Estimates based on the fluorescence data suggest that at least 90% of the coastal water was exchanged. The shifts in fluorescence intensity and structure were concomitant with a >99% reduction in the concentration of tracer dye added to the ballast tanks during ballasting in the ports of origin. In contrast, changes in phytoplankton and zooplankton species composition and diversity were not as great, which limit their potential for verification of mid-ocean exchange. The consistently low fluorescence intensity and lack of fluorescence structure of mid-Pacific ocean water relative to the coastal waters, and the stability of the fluorescence in the ballast tanks before and after exchange, suggest that fluorescence techniques can form the basis of verifying the presence of open ocean water in ballast tanks. KEY WORDS: Ballast water exchange · Aquatic nuisance species · Non-indigenous species · Coloured dissolved organic matter · CDOM · UV fluorescence Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 331. Online publication date: February 16, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Bridging Troubled Waters: Biological Invasions, Transoceanic Shipping, and the Laurentian Great Lakes

Abstract Release of contaminated ballast water by transoceanic ships has been implicated in more than 70% of faunal nonindigenous species (NIS) introductions to the Great Lakes since the opening of the St. Lawrence Seaway in 1959. Contrary to expectation, the apparent invasion rate increased after the initiation of voluntary guidelines in 1989 and mandatory regulations in 1993 for open-ocean ballast water exchange by ships declaring ballast on board (BOB). However, more than 90% of vessels that entered during the 1990s declared no ballast on board (NOBOB) and were not required to exchange ballast, although their tanks contained residual sediments and water that would be discharged in the Great Lakes. Lake Superior receives a disproportionate number of discharges by both BOB and NOBOB ships, yet it has sustained surprisingly few initial invasions. Conversely, the waters connecting lakes Huron and Erie are an invasion hotspot despite receiving disproportionately few ballast discharges. Other vectors, includ...

Rationale for Ballast Water Treatment Standards to Minimize Translocation of Unwanted Species

The transfer of unwanted species via ships' ballast water has become recognized as a major problem worldwide. Thousands of species of plants and animals are transported around the world daily, and colonization leading to infestations of many species has been well documented. Individual countries as well as international regulatory agencies are currently attempting to manage this transport of unwanted species. Currently, ships are required to have ballast water management plans in place, and the only accepted management option is open-ocean ballast water exchange. Due to the limitations of this option, ship-board treatment techniques need to be developed, but, treatment goals and standards currently do not exist. This paper proposes a rational for establishing ballast water treatment standards, so that ship-board technologies can be developed. Specifically, this paper demonstrates that by carefully evaluating past invasions, a group of organisms can be identified which pose a documentable risk of invasion. This group can then be classified by several common parameters, e.g., size, which allows for establishment of treatment options. It is then shown that the most rational standards are those mandating complete removal of high risk organisms, rather that a percentage removal of all organisms.