MBI summary – Volume 14 Issue 2 (June 2023)

This issue contains the proceedings of the 22^nd International Conference on Aquatic Invasive species, held in Ostend, Belgium, in 2022, starting with an Editorial about the return of ICAIS to Europe after 15 years and the impact of the global pandemic on the conference.

Monitoring of biological invaders is again a central theme in this issue. Environmental DNA (eDNA) was used to reveal the distribution, invasion fronts, and spatial configuration of invasion hubs of the American bullfrog (Lithobates catesbeianus) in Belgium. Also, eDNA-based assays were designed for the cost-efficient detection of the morphologically similar invasive amphipods Crangonyx pseudogracilis and C. floridanus and were subsequently applied across Europe. Additionally, it was demonstrated that satellite images can be used to detect Pontederia crassipes and Hydrocotyle ranunculoides, serving as suitable tools for large-scale, cost-efficient mapping of invasive aquatic macrophytes. However, high-tech methods are not always required for an efficient monitoring, as it was shown that rapid assessment surveys of floating pontoons in Ireland revealed a total of 25 non-native biofouling species, of which four were not previously reported. Even citizens can contribute to the detection of invasive alien species, as was shown for the invasive contained breeder Clogmia albipunctata that was found to be established in Sweden and Denmark through citizen-science.

Negative detections are evenly important as positive detections, especially since the patterns of zero and nonzero counts of Bigheaded carp (Hypophthalmichthys spp.) provide information about spatiotemporal distribution, aggregation and dispersion.

Relating monitoring data to environmental parameters can result in substantial synergies. It was found that high water temperatures were related to an increased mortality of invasive Zebra mussels (Dreissena polymorpha), and that dissolved oxygen concentration limited veliger distribution, suggesting that these parameters can “squeeze” them out of invaded reservoirs

Nonetheless, the monitoring and management conducted by wildlife and natural resource institutions may unintentionally result in movement and spread of invasive species. A conceptual framework is therefore included that evaluates institutional policies for invasive species prevention.

Buddhist life release practices are also a considerable pathway of invasive alien species in the USA. A survey of regional panels was able to provide guidelines on release practices that are acceptable in light of the problematics of biological invasions.

Laboratory and field comparisons of new and improved TFM bars to control larvae of invasive sea lampreys (Petromyzon marinus) were found to be superior over the conventional bar formulation.

It becomes increasingly clear that one must find ways to cope with biological invaders. It was found that for Australian redclaw crayfish (Cherax quadricarinatus), catch spoilage of fisheries could be significantly reduced by installing baited misdirection traps near gillnets in Africa.