Efficacy of calcein as a chemical marker of green-lipped mussel (Perna canaliculus) larvae and its potential use for tracking larval dispersal

An optimal chemical shell marking protocol was developed for the New Zealand green-lipped mussel, Perna canaliculus with a view to its future use in larval tracking experiments. Larval P. canaliculus aged either 10, 15 or 19days post fertilization were immersed in treatments of 50, 100 and 200mgL1 of calcein for a period of 24h before measurements of shell mark brightness were taken. There was 100% marking success in all calcein treatments for all age classes, with 19-day larvae immersed in 200mgL1 calcein producing the brightest mark. Growth was not affected by calcein immersion; however, 10-day larvae exhibited significantly higher levels of mortality compared with 15- and 19-day larvae suggesting a reduced resilience to the marking protocols in younger larvae. In a mass staining experiment, a solution of 100mgL1 calcein was used to successfully stain15.6 million hatchery reared P. canaliculus larvae. Calcein, therefore, offers a low impact method with which to stain the sensitive early life stages of this species thus providing a rapid method for identifying individuals of interest, i.e. individuals released in the wild or specific family lines within a hatchery environment.