Biological invasions, driven by the spread of non-native species, have become a critical global issue because of their far-reaching ecological and socioeconomic impacts. Effective communication of the risks of biological invasions is essential for implementing robust policy and legislation and gaining public support for conservation efforts. However, current policies often suffer from fragmentation and ineffectiveness, largely due to inadequate risk communication and complex multi-level governance. To address this challenge, we develop a global framework designed to enhance clearer communication about biological invasion risks. The framework contextualizes key terms across three domains in invasion science: species invasiveness, risk analysis, and decision support tools. Using both diffusion-of-English and ecology-of-language paradigms, and following a three-step process involving preliminary consensus, AI querying, and ground-truthing with final consensus, we validate the framework in 70 non-English languages which, together with English, have official status in at least one country and collectively cover all 195 countries worldwide. Our findings reveal that while terminology for risk analysis is well established, terminology for species invasiveness and, especially, for decision support tools remains underdeveloped in many languages, hindering effective communication and policy implementation. Our framework underscores the importance of cultural and political neutrality. By promoting clearer risk communication among scientists, policymakers, and the public globally, we aim to reduce policy fragmentation and foster enhanced collaboration in risk mitigation. We recommend expanding multilingual decision support tools to include the full risk analysis process: risk identification, risk assessment, and risk management. This will support intergovernmental mitigation efforts and promote a unified global response to biological invasions.

The establishment, spread, and impacts of aquatic invasive species (AIS) are accelerating globally, intensifying ecological and socioeconomic challenges for global fisheries requiring adaptive, context-specific strategies. Drawing on 11 AIS case studies, a global survey of 100 scientists, and an expert review panel of 21 scientists, we developed the recent technical paper Fisheries Responses to Invasive Species in a Changing Climate, published by the Food and Agriculture Organization of the United Nations. For established AIS, nine adaptive management measures were considered: (1) developing commercial fisheries, (2) promoting recreational harvesting, and (3) creating market opportunities to valorize AIS. To support these, (4) education and outreach and (5) stakeholder engagement are recommended to build awareness and co-management. Environmental strategies include (6) spatial control in priority areas, (7) biological control under strict conditions, and (8) ecological restoration. In some cases, (9) a “do nothing” approach may be justified when intervention is unfeasible or potentially harmful. Collectively, this analysis offers a flexible decision-support framework informed by available evidence, expert consensus, and practical experience. As climate change continues to reshape aquatic systems and modulate invasion dynamics, these strategies offer essential guidance for sustaining biodiversity, ecosystem services, and livelihoods in fisheries affected by AIS. Ultimately, their effective application will depend on a series of specific factors, which often include coordinated governance, adaptive policy, and inclusive science-policy dialogue.

This study highlights the role of ballast water management in preventing the global spread of harmful organisms. The entry into force of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments has created new challenges for policy and environmental managers. To adapt the most effective prevention strategies and enhance biosafety in the context of ballast water management systems, there is an increasing need for rapid analytical tools to detect microbes and assess the efficacy of ballast water treatment systems. In this study, ballast water was sampled from vessels before and after treatment at the port of Klaipeda, situated on the Baltic Sea coast. Results showed high levels of coliforms and Escherichia coli in untreated ballast water, with reduced levels after treatment, although statistical differences were not significant. No toxigenic Vibrio cholerae was found, but prior studies confirm the presence of other pathogenic Vibrio spp. Findings highlight the importance of ballast water monitoring and the potential for rapid monitoring methods to enhance biosecurity.

Managing non-indigenous species (NIS) is a key priority for natural resources managers, particularly as climate change increases the risk of these species becoming invasive. The lionfish (Pterois miles), an invasive NIS in the eastern Mediterranean and southern Aegean seas of Türkiye, has become a target for small-scale fishers (SSF) due to declining native fish stocks and NIS control efforts. A market-based approach to exploiting lionfish is a promising strategy, given the challenge of complete eradication in marine ecosystems – even though its commodification may carry unintended ecological and socio-economic risks in the long term. In Türkiye, despite market demand, fishers hesitate to supply lionfish due to potential gear damage and safe handling. This study examines the size selectivity and catch efficiency of thick trammel nets (TTNs), commonly used by SSF in Türkiye to overcome this barrier. Fishing trials from 2022 to 2024 mainly in the summer using TTNs with varying mesh sizes in the southern Aegean Sea caught 771 lionfish (18.2–42.7 cm total length). Results showed significant differences in mean total lengths across mesh sizes, with optimal model lengths exceeding the species’ first maturity length (L₅₀). Larger mesh sizes may meet market demand but are insufficient for population control, while smaller mesh sizes have an increased risk of bycatch of native species. Nevertheless, since TTNs generally have limited bottom contact compared to more destructive gear types such as trawlers and purse seiners, defining an optimal mesh size targeting lionfish has been the main aim of this study to inform decision-makers and SSF on best means available to tackle lionfish invasion in a collaborative way.

Invasive species guidelines recommend the early detection and rapid eradication of introduced species before they establish and spread. We adopted this approach to eradicate a recently introduced trout population from Timmelsjochsee, a small high mountain lake in the Austrian Alps, aiming to protect a rare melanic population of Daphnia longispina (“zschokkei” morphotype) inhabiting the lake. Eradicating introduced trout from originally fishless mountain lakes by intensive gillnetting is effective but typically time- and resource-intensive. This case study demonstrates that eradication can be achieved with minimal investment if carried out promptly, before the fish can establish. We deployed six multi-mesh gillnets over one year and monitored the native prey community (i.e., invertebrates and amphibians) throughout the process. Within a year, it appeared that all fish had been removed: seven adult Arctic charr (Salvelinus alpinus) and six adult rainbow trout (Oncorhynchus mykiss). Their similar size indicated that they had not yet established a reproductive population. The entire operation, including fish removal and field surveys, required eight days of fieldwork. During the eradication, the zooplankton community and the D. longispina (“zschokkei”) population did not show any obvious changes in density or composition. However, some changes in the littoral invertebrate community and in the common frog (Rana temporaria) population may indicate ecological recovery. The density of D. longispina (“zschokkei”) suggests that fish eradication occurred at an early stage during which the impact of such a small fish population was still minimal. This study provides an example of early detection and rapid eradication as a cost-effective restoration method. It underscores the importance of monitoring fish introductions into high mountain lakes and taking immediate action to protect fragile ecosystems before costs and impacts escalate.

Numerous control methods are in use and under development to manage invasive carps in the United States. Commercial harvest, electric deterrents, and chemical toxicants, among other methods, are most efficient at targeting larger individuals. Research on methods to control recruitment of juvenile invasive carps has been limited. Our primary objective was to assess the vulnerability of juvenile invasive carp and common native forage species, gizzard shad (Dorosoma cepedianum) to native fish predators. Eighteen two-week long experiments, from April–October in 2015 and 2016, were conducted in experimental ponds with differing habitats (structure, vegetation, or open), simulating backwater habitats that are commonly used by juvenile invasive carps. Bowfin (Amia calva), channel catfish (Icatalurus punctatus), shortnose gar (Lepisosteus platostomus), hybrid striped bass (Morone saxatilis × Morone chrysops), largemouth bass (Micropterus salmoides), blue catfish (Ictalurus furcatus), flathead catfish (Pylodictis olivaris), walleye (Sander vitreus), northern pike (Esox lucius), and smallmouth bass (Micropterus dolomieu) were tested as predators of bighead carp (Hypophthalmichthys nobilis), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella), and gizzard shad. We observed prey survival rates across seasons, habitats, and predator species. Invasive carp odds of survival varied from those of native gizzard shad between years. Hybrid striped bass, largemouth bass, smallmouth bass, and northern pike were effective predators of all tested prey species. Largemouth bass and smallmouth bass consumed bighead carp and silver carp over gizzard shad and grass carp (log OR < 0.5). Our results demonstrate the importance of habitat and cover availability, and that predator management may be a potential control method for juvenile invasive carps. Future research may consider effective predator densities, as well as studies in natural habitats.

Grass carp (Ctenopharyngodon idella), bighead carp (Hypophthalmichthys nobilis), silver carp (H. molitrix), and black carp (Mylopharyngodon piceus), collectively “invasive carp,” represent an ongoing management problem in the Mississippi and Missouri River basins of North America. Development of strategies to control their populations are also ongoing. As a follow-up to previous research, we tested two amino acids and an amino acid-based commercial feeding stimulant as olfactory stimulants that may attract or repel these species. We employed a two-pronged approach to test how invasive carp respond to the olfactory stimulants, using an electro-olfactogram (EOG) to measure olfactory response and a tank with a stimulant in one half to test behavioral response. Consistent with previous research, we found grass carp had a higher magnitude of EOG response to stimulants compared to bighead carp. However, neither silver nor black carp differed from each other or the other two species in terms of magnitude of EOG response. Lysine resulted in a greater response compared to alanine for black carp while it resulted in a lesser response compared to the commercial feeding stimulant for silver carp. In the behavioral tests, grass carp generally avoided the stimuli tested, while bighead carp were generally attracted to stimuli. Neither black nor silver carp showed a clear attraction or avoidance toward the stimuli tested. To further evaluate these solutions for management applications additional testing in ponds or open water may be necessary.

Common carp (Cyprinus carpio) is one of the world’s most widely distributed invasive fishes. Their high abundance and destructive feeding habits often lead to eutrophication, high water turbidity, and decimation of aquatic macrophytes. A relatively new control method for carp uses pop-up net systems (“box nets”) and bait placed within the net. Carp can quickly learn the bait location, which is often carp-specific, and form feeding aggregations, allowing large numbers of carp to be removed without significantly impacting native fish. However, the efficacy of box nets depends on the size and synchronization of carp feeding aggregations. Here, we investigated if acoustic conditioning might be used to enhance bait-induced carp feeding aggregations in a lake. Two study sites were established in Harrisons Bay, Lake Minnetonka, Minnesota, USA, in which 142 carp were tagged with passive integrated transponder (PIT) tags. Each site was subjected to sound-plus-bait, bait-only, sound-only, and no-stimuli treatments over the summer while the presence of carp visiting each site was continuously monitored using PIT antennas. While the carp did not respond significantly to the acoustic cue alone, pairing it with bait seemed to contribute to more synchronized feeding aggregations, resulting in faster and greater recruitment of carp to the sites after bait was dispensed. Specifically, the sound-plus-bait treatment was expected to recruit, on average, 11% more carp than the bait-only treatment. Further, the time to recruit 90% of the nightly tags decreased by 28% when bait was administered with the acoustic cue vs. alone. These findings suggest that adding an acoustic cue to bait applications might enhance the efficiency of bait-and-removal strategies and accelerate control of common carp populations.

Zebra mussels (Dreissena polymorpha Pallas, 1771) are an invasive mollusk that cause severe ecological and economic impacts on North American water resources. More information is needed on viable operational management options to control this invader and restore water use and ecology. This study evaluates the effectiveness of a chelated copper molluscicide (Natrix®) for controlling adult zebra mussels under in situ mesocosm conditions in Lake Minnetonka, Minnesota. Zebra mussel mortality and impacts to nontarget invertebrates were assessed in response to sustained free copper exposures of 0.5 and 1.0 mg Cu/L formulated as copper ethanolamine complexes. Copper concentrations, water temperature, pH, dissolved oxygen, and specific conductance were routinely monitored throughout all mesocosms. Results demonstrated a concentration and duration-related response, with 100% mortality of zebra mussels achieved at 0.5 mg Cu/L after 72 hours of exposure and 100% mortality achieved after 48 hours of exposure at 1.0 mg Cu/L. Water quality analyses revealed that environmental conditions were compatible with zebra mussel requirements and did not impact treatment outcomes. Non-target effects on benthic invertebrates showed no differences in the low-dose treatment, though there was a decrease in the numbers of invertebrates, but not taxa richness, in the high-dose treatment. This research provides valuable information to water resource managers on a chelated copper molluscicide to better inform zebra mussel management decisions.

The economic and environmental impacts associated with aquatic invasive species (AIS) introductions continue to rise, despite ongoing prevention measures. Education and outreach messages are foundational to prevention and the most effective messaging targets both specific behaviors and audiences. Most often, message development relies on self-reported behaviors which, while informative, can also be inflated due to social desirability or recall issues. Thus, obtaining objective behavioral information is essential to understand the situational context and what prevention behaviors are actually performed. Such knowledge can inform messages for specific behaviors and, theoretically, improve the likelihood of their completion. To that end, we observed boating anglers as they left select public water accesses in Minnesota to inform message development among an important segment of the boating community. Of particular interest were behaviors that complied with required and recommended actions such as removing vegetation from the boat, trailer, and equipment, removing the drain plug, cleaning equipment, and draining water from boat compartments and bait buckets. Across the summer of 2023, we observed 193 vessels at four accesses selected due to their comparability in design, traffic, and similarity in size and boating/angling resource. The majority of observed boating anglers took at least some of the required and/or recommended behaviors to prevent the spread of AIS. However, fewer than 50% comprehensively completed all required behaviors in accordance with Minnesota AIS prevention laws before leaving the public launch area. This gap represents an opportunity to improve prevention, education, and outreach among boating anglers to further limit the spread of AIS.

Awareness and behavior change campaigns are key tools in efforts to manage environmental problems, including the unwanted impacts of aquatic invasive species (AIS). Stop Aquatic Hitchhikers! and Clean Drain Dry are two common, nationally recognized brands used to target recreational boaters with an AIS-prevention messages within the United States. Despite how often these AIS awareness brands are used, though, there is limited evidence that these brands are associated with boaters performing AIS-prevention behaviors. To investigate the impact of these brands, we used data from a national survey to determine factors that are related to boaters’ self-reported frequency of performing AIS-prevention behaviors. Of the measured factors, overall awareness of AIS and awareness of Stop Aquatic Hitchhikers! and Clean Drain Dry were the most significant variables in predicting performance of AIS-prevention behaviors. This suggests that awareness of these commonly used brands is having a desirable impact on recreational boaters performing AIS- prevention actions and leveraging these brands and associated outreach materials is an effective method of outreach.