Introduction Of Non-indigenous Species Research Articles

Trade of live bait in Portugal and risks of introduction of non-indigenous species associated to importation

Different invertebrate groups are often exploited on sediment shores and mudflats, including polychaetes, sipunculids, bivalves and crustaceans. The commercial importance of polychaetes and sipunculids, that has increased in the early 2000's because of its use as a food source for the aquaculture sector and a growing demand of worms for use as sea angling bait, seems to be declining nowadays. In Portugal bait harvesting from natural populations became insufficient to meet market demands and as a result, polychaetes and sipunculids have been imported in recent years. Due to this it was important to know the ways of the live bait import to Portugal, and to assess the risk of introduction of non-indigenous species associated to that live bait trade. The origin and quantities of imported live bait were determined by examining the landing's records at Lisbon airport, from two periods: 2002–2003 and 2012–2015. Live worms imported to Portugal arrived almost exclusively from China, USA and Vietnam. Monthly import data and bait registers at fish auction landings were significantly correlated, showing that bait captures and imports are directly related to higher bait demand. In addition, the risk of live bait's importation as an introduction vector for non-indigenous species was evaluated by examining the bait boxes content. Five worm species were identified in bait boxes with foreign species: Glycera dibranchiata, Namalycastis rhodochorde, Perinereis cultrifera, Perinereis linea, and Sipunculus (Sipunculus) nudus. The examination of bait boxes in Portugal suggested that there is a low risk of associated hitchhiker species introduction and dissemination, mostly because of packaging procedures, which should be advised. The same is not true to the non-indigenous live bait species.

Seasonal and interannual variability of mesozooplankton in two contrasting estuaries of the Bay of Biscay: Relationship to environmental factors

Seasonal and interannual variations of total mesozooplankton abundance and community variability were assessed for the period 1998–2005 at 3 salinity sites (35, 33 and 30) of the estuaries of Bilbao and Urdaibai (southeast Bay of Biscay). Spatial differences in mesozooplankton seasonality were recognized, both within and between estuaries, related to differences between sites in hydrodynamic features and anthropogenic nutrient enrichment that drive phytoplankton biomass seasonal cycles. The within estuary seasonal differences in mesozooplankton community were mainly shown through seaward time-advances in the seasonal peak from summer to spring along the salinity gradient, linked to differences in phytoplankton availability during the summer, in turn, related to nutrient availability. These differences were most marked in the estuary of Urdaibai, where zooplankton seasonal pattern at 35 salinity (high tidal flushing) resembled that of shelf waters, while at 35 of the estuary of Bilbao zooplankton showed an estuarine seasonal pattern due to the influence of the estuarine plume. Cirripede larvae contributed most to the mesozooplankton seasonal variability, except at the outer estuary of Bilbao, where cladocerans and fish eggs and larvae were the major contributors, and the inner estuary of Urdaibai, where gastropod larvae contributed most. Total mesozooplankton increased at 30 salinity of the estuary of Bilbao and 35 salinity of the estuary of Urdaibai. Interannual variability of mesozooplankton at the lowest salinity of the estuary of Bilbao was mainly accounted for by copepods due to the introduction of non-indigenous species during estuarine rehabilitation from intense pollution. However, bivalve larvae and gastropod larvae showed the highest contributions at 35 salinity of the estuary of Urdaibai. At the rest of sites, the opposite interannual trends of polychaete larvae and hydromedusae generally made the highest contribution.

Recent introduction of non-indigenous vermetid species (Mollusca, Vermetidae) to the Brazilian coast.

The present study describes the bioinvasion of the vermetid gastropod Eualetes tulipa of the Brazilian coast. The species was first reported in the Pacific Ocean, off the coast of Panama (since the 1840s); however, the type locality was not specified in the original species description. Since then, E. tulipa has been introduced to Hawaii, the Caribbean Sea, southeastern Florida and India. In Brazil, the first documented occurrence was in 2005, at Ceara State, northeast Brazil, and later in 2009 it was registered at Rio de Janeiro State, southeast Brazil, 3000 km from the previous location. Nowadays, they are not only found growing on artificial substrates but also along sandstone fringing reefs and rocky reefs coexisting with the native species Petaloconchus varians. The impact on the native benthic community is unknown; however, studies have suggested impacts such as competing for space with fouling communities (E. tulipa, Venezuela), and causing deleterious effects on corals (Ceraesignum maximum, French Polynesia). The possibility of spread through Brazilian endemic areas (e.g. Abrolhos Marine National Park), is a legitimate cause for concern as a result of oil industry shipping further distributing this non-indigenous species. E. tulipa has a continuous year-long reproduction and fast settlement, within 24 h of hatching. This reproductive mode allows for the highly successful invasion and establishment to new areas following maritime transport or natural rafting, predicting a rapidly widespread distribution and invasion of Brazilian and International waters.

Development of an ATP assay for rapid onboard testing to detect living microorganisms in ballast water

Ballast water is a principal pathway for the introduction of pathogens and non-indigenous species to ports worldwide. The International Maritime Organization (IMO) and the United States Coast Guard (USCG) have adopted ballast water management regulations that require, e.g., the installation of shipboard ballast water management systems (BWMS). Rapid and simple analytical methods are needed to monitor whether ballast water disinfection ensures compliance with the discharge standards. In this study laboratory and full scale land-based testing was used to investigate the suitability of an adenosine triphosphate (ATP) assay for quantifying living organisms (≥10 and <50μm minimum dimension) in ballast water. In laboratory experiments the ATP assay was highly sensitive, with a detection limit of <5 cells 0.1mL−1. Diatom species (Chaetoceros simplex and Skeletonema costatum) had low ATP concentrations compared with dinoflagellate, Raphidophyceae, and Chrysophyceae species. This was because of differences in cell volume, as the ATP concentration increased exponentially with increasing cell volume. Using a regression model between ATP concentration and cell volume, an estimated the pass and fail ATP concentration in this study (788–98,610pgmL−1) was developed for the discharge of ballast water. In land-based testing the ATP assay also showed a good correlation with the presence of living natural plankton cells in control samples, but the ATP concentration (137pgmL−1) was much lower than the ATP guideline. The low ATP concentration in natural plankton cells may reflect a decline in their biological activity because of extended exposure to dark conditions. Although our results need further validation, the ATP assay is a suitable tool for monitoring compliance of ballast water treatment.

Threatened Fishes of the World: Telestes Croaticus (Steindachner, 1866) (Cypriniformes: Cyprinidae)

Abstract Telestes croaticus is a freshwater fish endemic in Croatia. It is a stygophile species, living above ground but occasionally retreating into subterranean waters. This species is found in the southwest region of Croatia, in the Lika-Jadova and Ričica drainages, in cold and clear waters in lowland habitats with little current, and in springs and associated wetlands. It is protected under Croatian law and was listed by the IUCN Red List as Endangered (EN). It has an extremely limited distribution which makes it vulnerable to different kind of traits such as habitat destruction, water extraction, dam construction, agricultural water pollution and especially the introduction of non-indigenous fish species. Suggested conservation actions for this species are: bans on watercourse regulation, reduction of pollution and eradication of alien fish species. Due to its fast decline in the last 10 years, it is our proposition that T. croaticus should be upgraded to a Critically Endangered species under criterion A2ace A4ace.

Evidence-Based Decision Making to Underpin the Thresholds in New Zealand's Craft Risk Management Standard: Biofouling on Vessels Arriving to New Zealand

AbstractVessel biofouling is a significant pathway for the introduction of nonindigenous marine species (NIMS). New Zealand is the first nation to regulate the vessel biofouling pathway, with controls scheduled to come into force in May 2018. The Craft Risk Management Standard (CRMS): Biofouling on Vessels Arriving to New Zealand specifies the hull fouling thresholds that vessels must meet; and here, we present the evidence-based decisions that underpin these thresholds.Under the CRMS, a vessel must arrive in New Zealand with a “clean hull,” the thresholds for which are governed by the intended duration of a vessel's stay in New Zealand. For example, long-stay (≥21 days) vessels must meet a more stringent standard of hull cleanliness due to the increased likelihood of release and establishment of NIMS. While setting a clean hull threshold at “slime layer only” can be tractable when vessels operate within the specifications of antifouling coatings, incidental amounts of macrofouling can establish even under the best management practices. Because of such instances, the thresholds within the CRMS were designed to allow for the presence of some macrofouling species, albeit with restrictions to minimize biosecurity risk. These thresholds are intended to limit species richness and to prevent successful reproduction and settlement of the allowed taxonomic groups while considering the practicality and feasibility of implementation.The difficulties of managing biofouling on different areas of the hull are acknowledged within these thresholds. For example, a greater tolerance of macrofouling has been allowed for niche areas due to the difficulties in preventing biofouling on these areas.

Evaluating efficacy of filtration + UV-C radiation for ballast water treatment at different temperatures

To prevent new ballast water-mediated introductions of aquatic nonindigenous species (NIS), many ships will soon use approved Ballast Water Management Systems (BWMS) to meet discharge standards for the maximum number of viable organisms in ballast water. Type approval testing of BWMS is typically conducted during warmer seasons when plankton concentrations are highest, despite the fact that ships operate globally year-round. Low temperatures encountered in polar and cool temperate climates, particularly during the winter season, may impact treatment efficacy through changes in plankton community composition, biological metabolic rates or chemical reaction rates. Filtration+UV irradiance is one of the most common ballast water treatment methods, but its effectiveness at low temperatures has not been assessed. The objective in this study was to examine the efficacy of filtration+UV-C irradiation treatment at low temperatures for removal or inactivation of phytoplankton and zooplankton populations during simulated ballast water treatment. Organisms from two size classes (≥10 to <50μm and ≥50μm) were identified and enumerated using microscope and culture techniques. The response of organisms in both size categories to UV-C irradiation was evident across a range of temperatures (18°C, 12°C and 2°C) as a significant decrease in concentration between controls and treated samples. Results indicate that filtration+UV-C irradiation will be effective at low temperatures, with few viable organisms ≥10 to <50μm recorded even 21days following UV exposure (significantly lower than in the control treatment).

Hydroid diversity of Eilat Bay with the description of a new Zanclea species

ABSTRACTEilat Bay is located at the southernmost tip of Israel in the Gulf of Aqaba (Red Sea). The list of hydroids currently known from there includes 51 species, and when extending it to the entire Red Sea, it includes 157 species belonging to 41 families. Nevertheless, the information regarding hydroids in the Gulf of Aqaba, and in particular in Eilat Bay, is not exhaustive. The aim of this work is to improve knowledge of hydroid biodiversity in this area. The specimens collected during the HyDRa project (Hydroid Diversity of the Northern Red Sea) revealed the presence of 27 species, 13 Anthoathecata and 14 Leptothecata, belonging to 17 families and 20 genera. Two families, Cladonematidae and Corynidae, and five genera, Cladonema, Slabberia, Campanularia, Nemalecium and Lafoeina, are new findings for the Red Sea. Furthermore, Nemalecium lighti, Zanclea gallii and the new species Zanclea eilatensis sp. nov. have never before been recorded in the Red Sea. Zanclea eilatensis sp. nov. lives in association with a bryozoan, has a monomorphic colony lacking a perisarc and only has stenoteles in the polyps. The medusa stage has two prominent perradial exumbrellar nematocyst pouches and two tentacles with about 50 cnidophores having long flagella and containing macrobasic euryteles. In the present work, 54% of the species were associated with other organisms, such as hydroids, corals and bryozoans. New ecological data about the Zanclea–scleractinian coral association are documented. The present investigation provides new information about diversity in the Red Sea, and in particular in Eilat Bay. In addition, our data also have significance for Mediterranean and Red Sea biodiversity conservation due to the recent expansion of the Suez Canal and the consequent possible increase in the introduction of nonindigenous species in both directions.http://zoobank.org/urn:lsid:zoobank.org:pub:C9EA7333-B9DF-4888-A643-4D45E6CD31CB

Rapid assessment of non-indigenous species in the era of the eDNA barcoding: A Mediterranean case study

With only a narrow opening through the Gibraltar and Suez Canals, the Mediterranean Sea is one of the largest semi-enclosed seas. The marine flora and fauna are some of the richest in the world, relative to its size, particularly in the coastal habitats, which are also characterized by numerous endemic species although the introduction of non-indigenous species threatens its rich and unique biodiversity. Following the opening of the Suez Canal, and in combination with shipping and aquaculture activities, non-indigenous species (NIS) introduction has had measurable impacts on the Mediterranean. Lagoon ecosystems along the French coastline, with approx. 100 NIS identified, are considered hot-spot areas for these species. Rapid assessment sampling for sessile benthic species together with DNA barcoding is a rapid, easy and cheap method to detect non-indigenous species. Two nearby and different ecosystems were sampled for invertebrate species: Saint-Nazaire lagoon, a Special Protection Area within the Natura 2000 Network and Canet port, a marina in a small village. The DNA barcoding tool for species identification was used for confirming the taxonomy. This showed that, despite the Saint-Nazaire Lagoon classification within the Natura 2000 network, it is already contaminated with a single NIS that was found in high densities and is clearly beginning to dominate the system. It is proposed that a rapid assessment of the sampled environment and the DNA barcode approach are efficient and can provide sufficient information on the new target species to be used in conservation planning and ongoing management efforts.

Interspecific Hybridization of Tilapiines in Lake Victoria, Kenya

Before the introduction of non-indigenous species like Oreochromis niloticus and Tilapia zillii (Gervais) in Lake Victoria, the great majority of the ichthyofauna of the lake was made up of two groups of indigenous cichlids, the haplochromines and the tilapiines. The latter, although much less diversified, represented an important part of the total fisheries catch, and were a highly-valued food resource for the local community. Two species constituted this tilapia stock: Oreochromis variabilis (Boulenger) and O. esculentus (Graham). In less than 20 years, several hundreds of species have disappeared from Lake Victoria among which are these two native tilapias. Today, these two species are no longer present except in a few satellite lakes of Lake Victoria. Most of these populations are considered either as endangered or as having suffered genetic modification by hybridization with closely related introduced species. Tilapias are well known for their hybridizing abilities in the natural environment when native species are in contact with introduced species. The hybrids between O. niloticus and O. variabilis were observed before the latter species had disappeared from the lake. It also seems likely that O. esculentus hybridized with O. niloticus. In order to protect the remaining populations of native tilapias in this region, it is important to be able to characterize the endemic species genetically to determine their degree of genetic. This will make the conservationists know how to handle these species and if at all we have pure breeds for protection of biological diversity.

Modeling sampling strategies for determination of zooplankton abundance in ballast water

Ballast water has been a major source of non-indigenous species introductions. The International Maritime Organization has proposed performance standard that will establish an upper limit for viable organisms in discharged ballast. Here we test different sampling efforts for zooplankton in ballast water on a commercial vessel. We fit different probability density functions to find the most representative and evaluated sampling efforts necessary to achieve error rates (α, β) of <0.05. Our tests encompassed four seasonal trials and five sample volumes. To estimate error rates, we performed simulations which drew from 1 to 30 replicates of each volume (0.10–3.00m3) for mean densities ranging between 1 and 20 organisms m−3. Fieldwork and simulations suggested that >0.5m3 samples had the best accuracy and precision, and that the Poisson distribution fit these communities best. This study provides the first field test of a sampling strategy to assess compliance with the future IMO standard for large vessels.

New Arrivals: An Indicator for Non-indigenous Species Introductions at Different Geographical Scales

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.

A primer to metabarcoding surveys of Antarctic terrestrial biodiversity

AbstractIce-free regions of Antarctica are concentrated along the coastal margins but are scarce throughout the continental interior. Environmental changes, including the introduction of non-indigenous species, increasingly threaten these unique habitats. At the same time, the unique biotic communities subsisting in isolation across the continent are difficult to survey due to logistical constraints, sampling challenges and problems related to the identification of small and cryptic taxa. Baseline biodiversity data from remote Antarctic habitats are still missing for many parts of the continent but are critical to the detection of community changes over time, including newly introduced species. Here we review the potential of standardized (non-specialist) sampling in the field (e.g. from soil, vegetation or water) combined with high-throughput sequencing (HTS) of bulk DNA as a possible solution to overcome some of these problems. In particular, HTS metabarcoding approaches benefit from being able to process many samples in parallel, while workflow and data structure can stay highly uniform. Such approaches have quickly gained recognition and we show that HTS metabarcoding surveys are likely to play an important role in continent-wide biomonitoring of all Antarctic terrestrial habitats.

Rate of biological invasions is lower in coastal marine protected areas.

Marine biological invasions threaten biodiversity worldwide. Here we explore how Marine Protected areas, by reducing human use of the coast, confer resilience against the introduction of non-indigenous species (NIS), using two very different Pacific islands as case studies for developing and testing mathematical models. We quantified NIS vectors and promoters on Vancouver (Canada) and Moorea (French Polynesia) islands, sampled and barcoded NIS, and tested models at different spatial scales with different types of interaction among vectors and between marine protection and NIS frequency. In our results NIS were negatively correlated with the dimension of the protected areas and the intensity of the protection. Small to medium geographical scale protection seemed to be efficient against NIS introductions. The likely benefit of MPAs was by exclusion of aquaculture, principally in Canada. These results emphasize the importance of marine protected areas for biodiversity conservation, and suggest that small or medium protected zones would confer efficient protection against NIS introduction.

Population attenuation in zooplankton communities during transoceanic transfer in ballast water.

Successful biological invasion requires introduction of a viable population of a nonindigenous species (NIS). Rarely have ecologists assessed changes in populations while entrained in invasion pathways. Here, we investigate how zooplankton communities resident in ballast water change during transoceanic voyages. We used next‐generation sequencing technology to sequence a nuclear small subunit ribosomal DNA fragment of zooplankton from ballast water during initial, middle, and final segments as a vessel transited between Canada and Brazil. Operational taxonomic unit (OTU) diversity decreased as voyage duration increased, indicating loss of community‐based genetic diversity and development of bottlenecks for zooplankton taxa prior to discharge of ballast water. On average, we observed 47, 26, and 24 OTUs in initial, middle, and final samples, respectively. Moreover, a comparison of genetic diversity within taxa indicated likely attenuation of OTUs in final relative to initial samples. Abundance of the most common taxa (copepods) declined in all final relative to initial samples. Some taxa (e.g., Copepoda) were represented by a high number of OTUs throughout the voyage, and thus had a high level of intraspecific genetic variation. It is not clear whether genotypes that were most successful in surviving transit in ballast water will be the most successful upon introduction to novel environments. This study highlights that population bottlenecks may be common prior to introduction of NIS to new ecosystems.

Bryozoan diversity in the Mediterranean Sea: an update

This paper provides a current view of the bryozoan biodiversity of the Mediterranean Sea updating the checklist by Rosso (2003). Bryozoans presently living in the Mediterranean increase to 556 species, 212 genera and 93 families. Cheilostomes largely prevail (424 species, 159 genera and 64 families) followed by cyclostomes (75 species, 26 genera and 11 families) and ctenostomes (57 species, 27 genera and 18 families). Few families and genera make the bulk of this biodiversity whereas one third of families are monospecific. The number of species-rank taxa has increased by 81 in the last dozen years but most of these additions relate to the revision of material from old collections and to the introduction of non-indigenous species. Most of the bryozoan diversity is distributed in the coralligenous and dark and semi-dark cave biocoenoses followed by detritic bottoms. Diversity lowers in shallow-water vegetated bottoms and in bathyal habitats. Further increase in diversity is expected from investigation of still poorly known areas and habitats and the need for rapid assessment is remarked on in view of the management of Mediterranean habitats through the EU Marine Strategy Directive.

A fuzzy ‘boater’ model to detect fouling and spreading risk of non-indigenous species by recreational boats

Recreational boating is an unregulated and underestimated vector of spread of non-indigenous species (NIS) in marine environments. The risk of a single boat to spread NIS depends not only on the local environmental context, but also on the type of boat and on the boat owner's behaviour (hull cleaning and painting frequency, travel history). In this paper we present a model to assess the risk of fouling and spreading of NIS and its application to data derived from a questionnaire given to Italian boat owners. The model uses a two-levels fuzzy logic approach: (1) the first level assesses the risk of hull fouling and risk of spreading separately; (2) the second level combines the two separate risks in an overall index ranging from 0 (null risk) to 100 (highest risk) and measures the global risk of NIS introduction and spread through recreational boating. The questionnaire and the fuzzy model allow for a simple and rapid assessment of boats most likely to be infested. The proposed fuzzy model can be easily edited and adapted to context-specific ecological and social conditions. The results of this Italian study showed that 53.9% of the respondents were in the very-low and low risk categories, and 46.1% in the medium, high and very-high risk categories.Possible associations between some boaters habits and the fouling and spreading risk were explored using logistic regression analyses. The results indicate a high-risk profile of boat owner as an experienced sailor who visits many marinas during the summer season. Biosecurity guidelines, containment measures and awareness raising programmes should be implemented to prevent and avoid further spread of NIS in marine environments, and such management actions would benefit from the early detection of high-risk boats, and from the identification of profiles of boaters upon which these initiatives should be prioritized.

Predicting and mapping the risk of introduction of marine non-indigenous species into Great Britain and Ireland

Non-indigenous species (NIS) can have adverse environmental, economic and social impacts. Their management is now incorporated into key legislation, including the European Union (EU) Marine Strategy Framework Directive and the EU Regulation on the prevention and management of the introduction and spread of invasive alien species. Prevention of NIS introductions and the early detection of NIS following their introduction are recognised as the most effective approaches for reducing the potential impacts of NIS. This is true for most aquatic environments but especially so for the marine environment, where control and/or eradication are often not achievable. By assessing introduction vector activity, it is possible to identify coastal areas and specific locations where marine NIS may be more likely to be introduced. This study uses data relating to the activity of key introduction vectors; shipping, recreational boating and live animal aquaculture import, to estimate the relative risk of introduction of NIS around coastal regions of Great Britain and Ireland. Spatial analysis was used to create “heat” maps indicating coastal areas of increased relative risk of introduction of NIS by these vectors. The results of the present study will be crucial for the implementation of targeted vector management plans, supporting preventive strategies, and will facilitate a risk analyses of NIS threats to inform monitoring and surveillance programmes.

Morphological and molecular methods reveal the Asian alga Grateloupia imbricata (Halymeniaceae) occurs on Cantabrian Sea shores (Bay of Biscay)

:Introduction of nonindigenous species (NIS) via anthropogenic activities (i.e. shipping) has serious consequences for marine ecosystems. On shores of the Cantabrian Sea (northern Spain), there is no routine NIS screening combining molecular and anatomical methods. This makes the detection of inadvertent expansions of exotic species difficult. In this work, a screening of nonfoliose Grateloupia specimens combining morphological and DNA barcoding procedures (COI-5P and rbcL genes) was conducted in the marina of Gijón, Bay of Biscay. A reproductive population of G. imbricata was found. This is the first report of this introduced Asian seaweed in continental Atlantic Europe. The detection of this species on shores of the Spanish Atlantic is relevant biogeographically since other previous records in the North Atlantic suggest a stepping-stones route via the Azores and Canary Islands. Routine screenings for early detection of exotic algae is becoming a powerful risk assessment tool for further introductions.

Non-indigenous fish in the northern branch of the central European invasion corridor

The assessment of risks associated with non-indigenous species implies a detailed knowledge of their taxonomical composition and distribution within a certain region. The northern branch of the central European ‘invasion corridor’—a series of canals connecting different watersheds—has formed an important migratory route for Ponto-Caspian fish (i.e. fish from the Black Sea, the Sea of Azov and the Caspian Sea). However, the current status of non-indigenous fish species in this region is very scarce. This article presents a comprehensive overview of recent distribution data of non-indigenous fish species in the northern branch of the central European invasion corridor. Here, extensive data are integrated based on studies performed during 2003–2014 comprising reliable published and unpublished records from the last 12 years. Altogether, ten non-indigenous fish species were currently found in the northern branch of the central European invasion corridor, constituting 19 % of its freshwater fish diversity. Three species, including the Prussian carp (Carassius gibelio), the round goby (Neogobius melanostomus), and the Chinese sleeper (Perccottus glenii), are considered invasive species. Eight species may potentially invade this region in the near future. A comparison of the history of non-indigenous fish species introduction in the inland waters of the northern branch and other countries of the central European invasion corridor revealed similar introduction trends. Potential expansion of non-indigenous fish species across the central European invasion corridor has international implications that require awareness, cooperation, and government support from each individual country. Disclosure of recently operating vectors for non-indigenous fish introductions within the central European invasion corridor will help predict and prevent their further spread and establishment in this region.