This special issue of Management of Biological Invasions includes applied papers presented at the 2018 International Invasive Sea Squirt Conference held at Woods Hole, Massachusetts, USA, May 2-4, 2018, and at the 10th International Conference on Marine Bioinvasions held in Puerto Madryn, Argentina, October 16–18, 2018.

Four papers were presented at the International Invasive Sea Squirt Conference:

 Carman et al. (2019) surveyed ascidians within eelgrass meadows in the USA and Canada and found eight species colonizing eelgrass, of which four were non-native and one was cryptogenic.

 Another eelgrass paper by Carman and Grunden (2019) examined the potential of crabs to consume ascidian-covered eelgrass. They found that the spider crab Libinia dubia consumed eelgrass fouled by Botryllus schlosseri and Molgula manhattensis, while the green crab Carcinus maenas did not.

 Zhang et al. (2019) examined the metabolic rates for two invasive and one native ascidian and found Didemnum vexillum to regenerate NH4 + faster.

 Osborne and Poynton (2019) report how invasive ascidian species are more tolerant to pollution - namely copper levels - which may give them an edge in interspecific competition.

 Two management-focused papers from the International Conference on Marine Bioinvasions are part of this joint special issue.

 Couton et al. (2019) shows how metabarcoding represents an efficient approach to the detection and study of non-indigenous species at an early planktonic larval stage, while highlighting the importance of building local reference collections.

 Finally, Cunningham et al. (2019) highlight the role of precautionary and proactive pathway management plans in mitigating the growing threat of marine bioinvasions, particularly in high value areas.

 Please visit our website and download Volume 10 Issue 4 of Management of Biological Invasions – it's Open Access!