The global mussel aquaculture industry relies heavily on the regular supply of wild seed mussels, to initiate aquaculture production. Supplies of wild mussel seed have a lower cost than seed produced in a hatchery, but wild seed are often highly variable in quantity, size, nutritional condition, which greatly affects their performance after being seeded out onto coastal mussel farms. For example, high losses of more than 80% of seed consistently occur within the first few weeks after seeding out in New Zealand’s green-lipped mussel (Perna canaliculus) (hereafter called GLM) industry. These losses have often been associated with the variability of nutritional condition of wild mussel seed prior to seeding.
GLM seed of 1.0 – 3.0 mm in shell length were starved for 0, 3, 6 and 9 days and then seeded onto a coastal mussel farm. Their subsequent retention on growing ropes after 2 weeks of seeding out onto the mussel farm was assessed. The nutritional condition of mussel seed both at the end of experimental starvation periods and after recovery from the farm was measured
The retention of GLM seed at the end of the experimental starvation tended to decrease with increasing periods of starvation, but was only significantly lower in mussel seed that were starved for 9 days. In contrast, the retention of mussel seed following seeding out in mussel farm was not different among mussel seed from different starvation periods (~30% across all treatments) (Figure 1).
The primary energy reserves, quantified as total carbohydrate of mussel seed decreased with increasing period of laboratory starvation treatment. Mussel seed that were starved for 9 days showed the lowest total carbohydrate content (16.5 ± 0.5 mg g tissue mass-1). After seeding out, total carbohydrate content of mussel seed from all starvation treatments were at similar level of mussel seed starved for 9 days in laboratory (Figure 2).