Match-mismatch between parturition and winter upwelling: Identifying oceanographic conditions that favor larval survival of winter-parturition rockfishes (Sebastes spp)

Recruitment variability to populations of winter-spawning rockfish (Sebastes spp.) arises primarily as a consequence of highly variable survival through the larval stage.  To identify conditions that favor survival of larval rockfishes, we developed simple models to relate variation in growth rates and survival of rockfish from parturition through the pelagic juvenile stage to environmental forcing of the coastal ocean, and compared the predictions from such models to the distribution of survivors’ backcalculated birthdates derived from pelagic juvenile rockfishes collected off central California from 1983 to 2004.  Results from this analysis indicate that wind-driven coastal upwelling, although often intermittent or of relatively low intensity, is a key determinant of whether larval rockfish released into the plankton encounter favorable conditions during the winter months.  Given a relatively constant distribution of parturition dates, these results provide a further step towards forecasting recruitment to winter-parturition rockfishes on the basis of environmental observations.