Role of nutritional history in the attachment and retention of green-lipped mussel spat

The global mussel aquaculture industry relies heavily on the use of wild seed mussels or spat to initiate aquaculture production. However, production efficiency is often compromised by the poor performance of spat following seeding onto aquaculture substrates such as grow ropes. A potential cause of poor performance of spat is compromised nutritional condition that can be associated with poor natural feeding conditions for wild spat immediately prior to harvest, as well as their subsequent inappropriate handling until seeding into aquaculture infrastructure. This study examines the importance of nutritional condition of spat to their subsequent attachment and retention after seeding into mussel aquaculture. Spat of the green-lipped mussel, Perna canaliculus, were experimentally starved for 0, 3, 6 and 9 days before being seeded into suspended culture in a coastal mussel farm. At the end of the laboratory starvation phase of the experiment the attachment, growth, soft tissue deposition and energy reserves (total carbohydrate content) of spat all tended to decrease with increasing starvation treatment. Fourteen days after seeding the spat to a mussel farm, there was a further general decrease in all of the observed variables in spat from their initial state at seeding out. The results suggests that after seeding to the mussel farm, the spat were subject to poor local feeding and environmental conditions and that conditions at mussel farms at the time of seeding spat may play an important role in determining early spat performance. While providing a short period of feeding for spat prior to seeding onto mussel farms will improve their immediate nutritional condition, growth and attachment, the subsequent performance of spat after seeding onto farms may be more dependent on ensuring favourable conditions at the farm site.