The Pelagic Phase of Spiny Lobster Development

Abstract

A reappraisal of the pelagic phase of development in palinurid lobsters, in conjunction with recent oceanographic data, shows that the ontogenetic changes in the vertical migratory behaviour of phyllosoma larvae operate as a biological strategy to effect larval recruitment. Wind-driven surface currents can transport the larvae in the opposite direction to the general circulation of the upper 300 m water layer. Ocean circulation charts are unreliable indicators of likely paths of larval transport because of their gross scale, lack of seasonal information, and the absence of indications of wind-driven surface currents. The majority of larvae are transported beyond the continental shelf to areas greater than 100 km offshore. This appears to be the principal source of larval recruitment to benthic populations, although some local recruitment from coastal areas may occur. Larval transport between populations of Jasus sp. in the Southern Ocean appears likely but is unconfirmed. For some insular populations this may be the sole, or major, source of recruitment. Delayed development of phyllosomata, or of pueruli, may account for year-round settlement in some species. Salinity changes are implicated as a factor stimulating metamorphosis from the final phyllosoma larval stage. The pelagic phase is completed by the nektonic, puerulus stage which swims (possibly directionally) across the continental shelf before settling and metamorphosing into the benthic stage.