Distribution and condition of pueruli of the spiny lobster Jasus edwardsii offshore from north-east New Zealand

Abstract

Pelagic spiny lobster, Jasus edwardsii, pueruli and phyllosomas were sampled on offshore transects from the south-east coast of the North Island of New Zealand in February 1998. Carapace length, weight, and total lipid content of pueruli (n = 360) were assessed; 33 pueruli had soft carapaces, indicative of recent metamorphosis from final-stage (stage 11) phyllosoma larvae. The recently metamorphosed pueruli occurred 24–216 km offshore, much farther offshore than has been previously suggested for the location of metamorphosis. Their distribution was compared to information on their size and condition, as well as their distance offshore, water depth, temperature and salinity, and estimates of phytoplankton biomass. The results indicate that a threshold of larval energy reserve is unlikely to trigger metamorphosis, but rather some exogenous trigger may be involved, or metamorphosis may be part of a programmed developmental process. The distribution and condition of the new pueruli suggest that about 84% had the energetic capacity to swim inshore to settle. This result may have important implications for patterns of puerulus settlement and subsequent recruitment of lobsters to coastal populations and their important associated fisheries. It may influence both the seasonal and interannual variability in settlement observed in this species.