Spiny lobster development: do the final-stage phyllosoma larvae of Jasus edwardsii swim towards the coast?

Several papers from New Zealand have all suggested that late-stages, or at least the final stage phyllosomas of Jasus edwardsii can swim horizontally from offshore to inshore towards the coast. This was largely based on the observation that the late-stage phyllosomas were distributed inshore of the mid-stage phyllosomas off the east coast of New Zealand. A review of these data, plus additional information on the diurnal vertical migration behaviour of the phyllosoma larvae of J. edwardsii not available at the time of publication of the earlier papers,suggests an alternative explanation. These new data clearly show different diurnal vertical migration behaviour of the mid and the late-stage phyllosoma. It is suggested that even small differences in the vertical movements of the phyllosoma larvae can result in dramatic changes in their horizontal distribution because these movements take them into different current layers and this, not horizontal swimming, is probably responsible for the different locations of the mid and late-stage phyllosomas of J. edwardsii off the east coast of New Zealand