Understanding the ontogenetic changes in particle processing of the greenshell™ mussel, Perna canaliculus, in order to improve hatchery feeding practices

Despite the commercial aquaculture importance of the Greenshell™ mussel, Perna canaliculus, the morphological development of gill structure (ctenidial filaments) in relation to potential particle feeding abilities have not been described. Scanning electron microscopy (SEM) and light microscopy were used to examine the ontogenetic changes across five size classes of mussels from post-settlement larvae to adults ranging from 300μm to >100mm in shell height. Key morphological characteristics were measured including filament width, the eulatero-frontal cirri (ELF) length, interfilamentary space (IFS) and the mean distance between adjacent ELF, dELF. Overall the development of the ctenidial filaments in P. canaliculus, shared some similarities to other homorhabdic filibranch bivalves with differences in the timing of development. Filament width and ELF length followed sigmoidal growth curves in relation to increasing shell height of mussels. The morphological changes of the ctenidia, reflected in changes in the ELF/IFS ratios, together with the development of cilia in the ELF may help explain the differences in the capture efficiency of small particles between small individuals (