Patterns of pelagic dispersal of the early stages of wild mussels are important ecologically for maintaining population connectivity, and economically for supplying wild seed for mussel aquaculture. However, it is difficult to trace the pelagic pathways of mussels due to their minuscule size, high abundance and interactions with the ocean environment. Microchemical methods can be used to infer locations of mussels during their pelagic journey by matching the trace metals sequentially deposited during the formation of the shells of the early stages of mussels to the chemical composition of the seawater in which the shell developed. This method was used to reconstruct the pelagic pathways for recently-settled green-lipped mussels, Perna canaliculus, sampled for two sequential 5-week periods, back to their natal locations for 22 sites covering a ∼110 km long coastal embayment in northern New Zealand. The majority (∼61 %) of the mussel settlers arrived at a specific part (∼25 km) of the coastline, and most of the settlers (∼84 %) were >
0.8 mm in shell length, indicating they were mostly juveniles undergoing secondary pelagic dispersal. Sequential microchemical analyses of the shells indicated that these juvenile mussels mainly (∼82 %) originated as larvae from a small length of the coastline (i.e., ∼12 km) with their larvae settling in the vicinity, prior to their subsequent pelagic dispersal as juveniles throughout the embayment. The mean net distance travelled by all sampled mussels was about 3-8 km higher than the mean dispersal distance to reach their primary settlement site (∼20 km) in these two sampling periods, suggesting that secondary pelagic migration by plantigrades extends the overall dispersal range in this species by about 15-41 %. These novel results allowed us to separate primary and secondary pelagic dispersal phases, and highlight the significance of the pelagic dispersal of juveniles subsequent to the initial dispersal of mussel larvae.