This publication was produced by ABARES for Plant Health Australia Overview Experience from overseas indicates that the cost of an incursion by black-striped mussel is likely to be large without management. This report presents a comparison of the estimated costs associated with the alternative responses to an incursion: eradication and containment. Hypothetical incursions of black-striped mussel in ten case study areas across four Australian ports were considered. The cost of eradicating the initial mussel incursion from a case study area is compared to the cost of containing the mussel population to the port encompassing the case study area. The findings indicate that eradication is in most cases the preferred and less costly option over a range of time scales with the caveat that the likelihood of successful eradication will depend on early detection and response. Key Issues * Mytilopsis sallei (black-striped mussel) is an invasive marine species that has been translocated from its native range in the Caribbean to a large number of ports in southern and eastern Asia. * An incursion of black-striped mussel in Darwin in 1999 was successfully eradicated at a cost of in excess of $3.2 million in 2012 terms. This species has been reported to have become established in a number of overseas trading ports, including Singapore, Hong Kong and Mumbai. The risks of translocation to Australia have therefore increased in recent years. * If an incursion by this species is not managed, it has the potential to cause significant and widespread economic and environmental damage. * A comparison of the costs associated with eradication with those of containment and control in a range of scenarios found that in many cases eradication is the preferred option, but containment and control may be preferred in some situations.