Towards reliable viability assessment for resilient life stages of invertebrates in ballast water This report presents results from the VIABLEGG project, which made important progress in identifying viable eggs and resting stages of invertebrates in ballast water. The findings show that some methods work well for certain species, offering practical value for inspections at ports. At the same time, the project provides new insight into why some life stages are difficult to assess and what biological and technical challenges must be addressed. The report offers concrete suggestions for future research, practical application, and the need for international coordination. These results lay a valuable foundation for efforts to prevent the spread of invasive species through global shipping. This report is financed by the Swedish Environmental Protection Agency and the Swedish Agency for Marine and Water Management.