The grass carp, Ctenopharyngodon idella, is an invasive species in North America that has been recorded in 45 states with breeding populations in several major river basins. Established populations of grass carp have had cascading, negative effects on aquatic ecosystem structure and function. Oral piscicide baits have been examined as a potential method to manage invasive grass carp. Our goal was to examine the oral toxicity of the dimethyl-dithiocarbamate fungicide, Ziram, to grass carp. Three toxicity experiments used different carriers to deliver single Ziram doses ranging from 0.25 to 250 mg/kg by gavage. No acute mortality was observed when grass carp were gavaged with Ziram at the highest concentrations dissolved in ethanol at 40 mg/kg, suspended in dimethyl sulfoxide (DMSO) at 250 mg/kg, or suspended in polyethylene glycol (PEG) at 150 mg/kg. Ziram exposure through intraperitoneal injection resulted in acute mortality at 150 mg/kg potentially due to increased residence time in the peritoneal cavity and thereby greater opportunity for absorption. These results indicate that Ziram is acutely toxic to grass carp, however, additional research is required to formulate a successful novel grass carp toxicant that can be used to target the invasive species while minimizing effects on non-target fish species.

On February 9–10, 2022, the Pacific States Marine Fisheries Commission, U.S. Fish and Wildlife Service, U.S. Geological Survey, and Washington State University hosted a workshop to establish research priorities that support the implementation of action items listed in a current invasive species management plan, the Quagga and Zebra Mussel Action Plan (QZAP) 2.0, that are intended to limit the establishment and spread of quagga and zebra mussels in the western United States. The workshop focus was on developing research priorities for the thematic areas that are addressed in QZAP 2.0: 1) early detection monitoring, 2) prevention and containment, 3) control and management, and 4) rapid response. In addition, research priorities were developed for a fifth thematic area that addressed dreissenid mussel biology. Forty scientists participated in the two-day workshop. Prior to the workshop, participants were asked to review and rank research priorities that were established for a previous version of the QZAP and to offer suggestions on emerging research priorities. During the workshop, subject matter experts presented information describing current knowledge of research and information associated with the thematic areas of early detection monitoring, prevention and containment, rapid response, control and management, and biology in the context of strategies and actions listed in QZAP 2.0. The rankings of previous research priorities and suggestions of emerging priorities were then reviewed, and a revised list of research priorities was formed. The list of research priorities is presented by thematic area.

Although there have been many attempts at eradicating exotic ant incursions, most efforts have been unsuccessful, and a lack of specific biological knowledge is believed to have been a major contributing factor. In early May 2013, an exotic ant species, Lepisiota frauenfeldi, was found for the first time in Australia. Identifying the species proved difficult, and little biological information about the species was available. In making the decision to eradicate and develop the treatment protocols, four assumptions were made about the ant’s biology. Here we detail rapid and basic research that was used to assess the assumptions underpinning the decision to eradicate, contribute to determine some eradication protocols for this understudied species, as well as how our understanding increased following the discovery of two other incursions of this species in Australia. The research found that all initial assumptions of the ant’s biology used in the original eradication plan were wrong. Distribution modelling found the ant could potentially inhabit a larger area than first thought, and updating the model with the subsequent incursions greatly increased the area of suitable climate in Australia. The ant’s foraging and reproductive regimes were not as expected, so too its nutrition pathways to queens, which had implications for the treatments. Our work serves as a clear warning for invasive species practitioners that management decisions that are based on assumptions, “gut feelings” or knowledge based on information from elsewhere in the world, or from other species, can be expected to be flawed. Rapid, small-scale and strategic research conducted on-site can enhance management outcomes.

Discharging untreated ballast waters supports the spread of invasive species. One of the most successful ballast-water mediated biological invasions was a transatlantic transport of the ctenophore Mnemiopsis leidyi to many Eurasian seas, where it has significantly impacted local ecosystems. To prevent its spread to new areas, we studied the survival of different M. leidyi life stages exposed to several eradication techniques. We looked closely into the technical applicability of an onboard thermal treatment by calculating its duration and the required energy to perform it. The duration was considered as a sum of the time to heat ballast tanks by using the engine’s waste heat for two types of ships and M. leidyi’s eradication. The calculated duration of the proposed treatment allowed us to estimate a minimum travel length undertaken by a specific type of ship to eliminate M. leidyi successfully. The travel length determines the appropriate technique and minimal requirements to eliminate M. leidyi successfully and, thus, can serve as a guideline for a management plan. In conclusion, the proposed onboard treatment would be efficient on smaller ships and minimum distances of 200–300 km depending on the season but not on the short routes where other treatment techniques, e.g. exposure to ultrasonic cavitation or microwave radiation, should be considered.

We present three studies assessing the efficacy and non-target impacts of multiple unregistered forms of hydrogel ant baits, as well as some co-use with the granular bait Antoff, that were experimentally used targeting Argentine ant, Linepithema humile, and yellow crazy ant, Anoplolepis gracilipes, within natural/semi-natural environments in Australia. The three studies varied greatly in design and treatment regimens, and were each conducted to address real-time learning needs while attempting to understand how best to use these experimental baits within the spatial, temporal and logistic limitations of three eradication programs. All studies involved broadscale applications of numerous forms of the baits, with greatly varying treatment regimens, coupled with before-after sampling of ant communities, as well as other soil invertebrates in one study. All studies found the baits were highly efficacious against both species, more so for A. gracilipes than L. humile. Eradication is considered to have been achieved for A. gracilipes in one treatment area with a triple treatment regimen, but not using different treatment regimens in other areas. Six treatments conducted approximately one week apart did not eradicate L. humile. Few non-target impacts were found, predominantly occurring only when sampling was conducted within days of a treatment, or at the end of six treatments of a high application rate. Instead, non-target species richness and composition were most often more affected by spatial location or sample time than treatment. Any treatment effects were non-persistent after 6–18 months. Hydrogel baits are likely to have significant roles to play for ant management and eradication.

Sun corals, Tubastraea spp., are native to the Indo-Pacific Ocean, but have established populations in different areas of the Atlantic Ocean. Tubastraea spp. are considered invasive in Brazil, being targets of a National Plan for Prevention, Control and Monitoring. One of the objectives of this plan is to develop scientific research and technology, focused on subsidies for the prevention and management of sun coral dissemination. Through manipulative experiments under controlled laboratory conditions, we analyzed the effects of exposure to air in sun coral colonies during different time intervals, to provide general biosecurity subsidies for possible management operations using desiccation. In addition, we recorded the coral ability to regenerate soft tissues damaged after trauma due to desiccation. We observed that Tubastraea sp. resists up to four hours out of seawater without permanent damage, despite being a typical subtidal organism. The number and severity of wounds and loss of soft tissues increased with exposure time to air, which affected the recovery capacity of this coral. Full mortality of the colonies (all polyps dead) was achieved only after four days of exposure to air. In addition, the healing regeneration process was recorded here for the first time in sun corals. The proportion of polyps partially retaining soft tissues involved in feeding is determining for the recovery of the entire colony, which can occur in just two weeks. Such data offer relevant biosecurity subsidies for possible management operations using desiccation.

Signatories to the Antarctic Treaty System’s Environmental Protocol are committed to preventing incursions of non-native species into Antarctica, but systematic surveillance is rare. Environmental DNA (eDNA) methods provide new opportunities for enhancing detection of non-native species and biosecurity monitoring. To be effective for Antarctic biosecurity, eDNA tests must have appropriate sensitivity and specificity to distinguish non-native from native Antarctic species, and be fit-for-purpose. This requires knowledge of the priority risk species or taxonomic groups for which eDNA surveillance will be informative, validated eDNA assays for those species or groups, and reference DNA sequences for both target non-native and related native Antarctic species. Here, we used an expert elicitation process and decision-by-consensus approach to identify and assess priority biosecurity risks for the Australian Antarctic Program (AAP) in East Antarctica, including identifying high priority non-native species and their potential transport pathways. We determined that the priority targets for biosecurity monitoring were not individual species, but rather broader taxonomic groups such as mussels (Mytilus species), tunicates (Ascidiacea), springtails (Collembola), and grasses (Poaceae). These groups each include multiple species with high risks of introduction to and/or establishment in Antarctica. The most appropriate eDNA methods for the AAP must be capable of detecting a range of species within these high-risk groups (e.g., eDNA metabarcoding). We conclude that the most beneficial Antarctic eDNA biosecurity applications include surveillance of marine species in nearshore environments, terrestrial invertebrates, and biofouling species on vessels visiting Antarctica. An urgent need exists to identify suitable genetic markers for detecting priority species groups, establish baseline terrestrial and marine biodiversity for Antarctic stations, and develop eDNA sampling methods for detecting biofouling organisms.

One of the most widespread and common invasive aquatic plant species in North America is Myriophyllum spicatum L. (Eurasian watermilfoil). Given the variety of impacts it has on ecological and recreational values, identifying an effective treatment strategy for Eurasian and hybrid watermilfoil is a priority for invasive aquatic plant management agencies. Unfortunately, traditional control efforts using herbicides have not only been variably effective, but they have also resulted in non-target impacts. The herbicide florpyrauxifen-benzyl (trade name ProcellaCOR®) has recently been approved but understanding of effectiveness is mostly limited to mesocosm studies. Our study reports the outcome of using florpyrauxifen-benzyl to treat a strain of hybrid watermilfoil in an inland lake in the Laurentian Great Lakes region. Mean abundance in treatment areas decreased at all points sampled (or stayed the same where initial cover was zero). Percent cover in the two quadrats declined from 50% to 5% in area 1, and 20% to 0% in area 2. Of the nine native plant species present, frequency of occurrence increased (six species) or stayed the same (three species) after treatment. Mean species richness at each transect increased pre- to post-treatment. The substantial decreases in this strain of hybrid watermilfoil abundance and increases in presence of native aquatic vegetation in this field study provide initial evidence that florpyrauxifen-benzyl is effective in partial-lake treatments of this strain of hybrid watermilfoil at an application rate of 12.68 oz/ac ft, with limited non-target impacts to native species. Our study balances observational studies with logistical management concerns to benefit researchers and lake stakeholders, alike. Study outcomes support recent advances in milfoil management that could lead to improved control, which translates to reduced ecological and recreational impacts of milfoil, as well as reduced non-target impacts and long-term management costs.

The presence of fish within navigation locks can introduce an environmental challenge for construction crews when maintenance is required. This study examined the effectiveness of a dual-deterrent fish herding technique using electricity and acoustic stimuli to reduce the abundance of fish within a navigation lock before a scheduled dewatering for maintenance. Fixed-location multi-beam imaging sonar was used to evaluate fish per minute (FPM) detections near the lock entrance before, during, and after the herding effort. Standardized mobile side-scan sonar surveys were also conducted before and after the herding to examine fish presence throughout the entire lock. Collectively, a 73% reduction in fish targets detected by side-scan sonar and a 43% reduction in FPM detected by imaging sonar were observed following the herding technique. Post-fish herding, an 88% reduction in FPM > 400 mm and a 35% reduction in FPM < 400 mm were observed. Fish abundance within the lock chamber was reduced and did not result in construction delays, which was problematic and costly during previous dewatering events. Because data from this study are limited to a single lock dewatering and fish clearing event, caution is warranted with the extrapolation of these results. However, the applied methods show promise and may inform future fish clearing efforts to aid lock maintenance.