Recovering mussel spat normally lost during seeding onto farms

Massive losses of mussel spat shortly after it is seeded onto coastal farms is a significant challenge for aquaculture. This initial study examined the potential for separating wild Greenshell™ ( Perna canaliculus ) mussel spat that were at high risk of being lost during seeding operations and then re-settling them onto new substrate and subsequently transferring them onto coastal mussel farms to recover spat that would be otherwise lost from production. Simply immersing the harvested wild spat material in seawater for 5 min prior to seeding onto a mussel farm resulted in the detachment of 11.2 % of the spat present in the material and enabling their recovery. A total of 82.0 % of the recovered spat could be re-settled onto cotton stocking substrate and seeded onto a coastal mussel farm, alongside the remaining harvested wild mussel spat material from which the spat had been separated. After 3.5 months, 9.5 % of the re-settled spat remained compared to 3.5 % in the originally harvested wild spat. Overall, this spat recovery process enabled more mussel spat to be retained after 3.5 months relative to the normal process for directly seeding harvested wild spat material directly onto coastal mussel farms. Further developing and applying this approach to harvested wild spat has the potential to greatly reduce overall mussel spat losses and lead to increased mussel aquaculture production. • Mussel spat that are at high risk of being lost during seeding operations can be recovered. • Detached spat can be re-settled onto new substrates and seeded for on-growing on mussel farms. • The spat recovery process has the potential to help reduce spat losses.