This special issue of Management of Biological Invasions includes an editorial and twelve applied papers from the 21^st International Conference on Aquatic Invasive Species (ICAIS) held in October 2019 in Montreal, Canada.

Special issue editors (Mattias Johansson, Brenda Koenig and Sarah Bailey) explain why

ICAIS is a unique forum for synthesizing knowledge of aquatic invasive species in their editorial.

Are you curious to learn more about novel tools and best practices for raising awareness about invasive alien species inside and outside classrooms? Read more here.

This study shows how structured decision-making is a useful tool for identifying shared goals, facilitating discussion and arriving at collective decisions in invasive species control.

A qualitative inquiry into the motivations and awareness of practitioners of Buddhist “life release” rituals in the United States offer new perspectives for reducing invasion risk.

A risk analysis for nine alien crayfish species in the Rhine-Meuse river (Netherlands) lists six possible strategies for population control.

Eradication of an invasive fish parasite affecting salmonids failed for a long time – but lessons learned led to a new and more effective strategy applied in Norway.

How to clean your boat? This review provides a useful overview of the effectiveness of different cleaning methods for recreational watercrafts.

An experimental study found that high-intensity hot water spraying is effective against killer shrimp (Dikerogammarus villosus) and zebra mussel (Dreissena polymorpha), but not for removing invasive aquatic plants.

Another good reason to check, clean and dry your boat! This study found that quagga mussels (Dreissena bugensis) can survive air exposure with wind speeds of 50 km/s for over 18 hours when attached to boat hulls.

This study shows that policies and regulations matter a great deal for the cost-effectiveness of ballast water treatment strategies.

Two papers highlight the importance of balancing effective control of invasive species with the risk of collateral damage to non-target species, including the use of glyphosate for controlling aquatic plants and EarthTec® QZ treatment for controlling New Zealand mud snails (Potamopyrgus antipodarum) in hatcheries.

Finally, this study investigated whether certain fish species will avoid water treated with biopesticides (or not).