Description: Damit ein Schiff unabhängig vom Beladungszustand stabil im Wasser liegt, muß ein Gewichtsausgleich durch Ballastwasser geschaffen werden. Dieses Wasser wird in den Häfen beim Be- und Entladen des Schiffes aufgenommen oder abgepumpt. Zusammen mit dem Ballastwasser können auch Pflanzen und Tiere (z.B. Algen, Kleinkrebse und Fische) mit aufgenommen werden, und so auf dem Seewege als „blinde Passagiere" weite Strecken zurücklegen. Findet ein eingeschleppter Organismus am Ziel seiner Reise günstige Bedingungen vor, so kann er sich dort massenhaft ausbreiten, und so zum ökologischen und ökonomischen Schädling werden. Ein Forschungsvorhaben von Umweltbundesamt, dem Institut für Meereskunde, Kiel, und der Universität Hamburg, soll nun klären, ob mit dem Schiffsverkehr eingeschleppte Organismen eine Gefahr für deutsche Gewässer darstellen.

Description: Highlights: • Monitoring of non-indigenous and cryptogenic species/populations needs to be initiated. • Monitoring should focus on bridgehead sites and dispersal hubs. • Monitoring methods should be internationally harmonized. • Rapid assessments of particular species may provide timely but limited information. • Monitoring data should be assembled in open access continually updated databases. Abstract: Non-indigenous species (NIS) are recognized as a global threat to biodiversity and monitoring their presence and impacts is considered a prerequisite for marine environmental management and sustainable development. However, monitoring for NIS seldom takes place except for a few baseline surveys. With the goal of serving the requirements of the EU Marine Strategy Framework Directive and the EU Regulation on the prevention and management of the introduction and spread of invasive alien species, the paper highlights the importance of early detection of NIS in dispersal hubs for a rapid management response, and of long-term monitoring for tracking the effects of NIS within recipient ecosystems, including coastal systems especially vulnerable to introductions. The conceptual framework also demonstrates the need for port monitoring, which should serve the above mentioned requirements but also provide the required information for implementation of the International Convention for the Control and Management of Ships Ballast Water and Sediments. Large scale monitoring of native, cryptogenic and NIS in natural and man-made habitats will collectively lead to meeting international requirements. Cost-efficient rapid assessments of target species may provide timely information for managers and policy-advisers focusing on particular NIS at particular localities, but this cannot replace long-term monitoring. To support legislative requirements, collected data should be verified and stored in a publicly accessible and routinely updated database/information system. Public involvement should be encouraged as part of monitoring programs where feasible.

Description: Several legal and administrative instruments aimed to reduce the spread of non-indigenous species, that may pose harm to the environment, economy and/or human health, were developed in recent years at international and national levels, such as the International Convention for the Control and Management of Ship's Ballast Water and Sediments, the International Council for the Exploration of the Sea Code of Practice on the Introductions and Transfers of Marine Organisms, the EU Regulation on Invasive Alien Species and the Marine Strategy Framework Directive, the US Invasive Species Act, the Biosecurity Act of New Zealand, etc. The effectiveness of these instruments can only be measured by successes in the prevention of new introductions. We propose an indicator, the arrival of new non-indigenous species (nNIS), which helps to assess introduction rates, especially in relation to pathways and vectors of introduction, and is aimed to support management. The technical precondition for the calculation of nNIS is the availability of a global, continuously updated and verified source of information on aquatic non-indigenous species. Such a database is needed, because the indicator should be calculated at different geographical scales: (1) for a particular area, such as port or coast of a country within a Large Marine Ecosystem (LME); (2) for a whole LME; and (3) for a larger biogeographical region, including two or more neighboring LMEs. The geographical scale of nNIS helps to distinguish between a primary introduction and secondary spread, which may involve different pathways and vectors. This, in turn, determines the availability of management options, because it is more feasible to prevent a primary introduction than to stop subsequent secondary spread. The definition of environmental target, size of assessment unit and possible limitations of the indicator are also discussed.

Description: In an assessment of non-indigenous species transported by international ship traffic to German waters, commissioned by the German Federal Environmental Agency, the survival of tropical plankton organisms in ballast water was studied by accompanying a container vessel on its 23-day voyage from Singapore to Bremerhaven in Germany. Two tanks, one filled off Singapore and the other off Colombo, Sri Lanka, were monitored for their phyto- and zooplankton content by daily sampling. As already reported in previous studies, species abundance and diversity, especially of zooplankton, decreased sharply during the first days, and only a few specimens survived the whole cruise. The contents of the Colombo tank, however, changed dramatically during the last week. The harpacticoid copepod, Tisbe graciloides, increased its abundance by a factor of 100 from 0.1 to 10ind. l–1 within a few days. This is the first time that a ballast water organism has been found to multiply at such a high rate. Opportunistic species such as Tisbe are apparently able to thrive and propagate in ballast water tanks under certain conditions. Ballast water tanks may thus serve as incubators for certain species depending on their characteristics.

Description: The most effective way to manage species transfers is to prevent their introduction via vector regulation. Soon, international ships will be required to meet numeric ballast discharge standards using ballast water treatment (BWT) systems, and ballast water exchange (BWE), currently required by several countries, will be phased out. However, there are concerns that BWT systems may not function reliably in fresh and/or turbid water. A land-based evaluation of simulated ‘BWE plus BWT’ versus ‘BWT alone’ demonstrated potential benefits of combining BWE with BWT for protection of freshwater ecosystems. We conducted ship-based testing to compare the efficacy of ‘BWE plus BWT’ versus ‘BWT alone’ on voyages starting with freshwater ballast. We tested the hypotheses that there is an additional effect of ‘BWE plus BWT’ compared to ‘BWT alone’ on the reduction of plankton, and that taxa remaining after ‘BWE plus BWT’ will be marine (low risk for establishment at freshwater recipient ports). Our study found that BWE has significant additional effect on the reduction of plankton, and this effect increases with initial abundance. As per expectations, ‘BWT alone’ tanks contained higher risk freshwater or euryhaline taxa at discharge, while ‘BWE plus BWT’ tanks contained mostly lower risk marine taxa unlikely to survive in recipient freshwater ecosystems.