There are two New Zealand green-lipped mussel populations. The Northern and Southern populations split south of Cook Strait. There are no stock assessments for the species but a Quota Management System began in 2004, with eight management sub-units (GLMs) at national level. The northern green-lipped mussel population extends along the GLMs 1, 2, 8, 9 and 10, while the southern green-lipped mussel population extends along the GLMs 3, 7A and 7B (MPI 2014).