Larval Striped Bass (Morone saxatilis) Otolith Development

Otolith studies have become more prevalent in recent years as use has expanded from only aging to examination of migration and fidelity to natal habitats.  The otolith of striped bass, Morone saxatilis, is used for all of these purposes, yet its formation and early development have not been documented.   We identified the timing and formation of the three otolith pairs during late pre-hatch embryo, post-hatch larvae, and metamorphosis.  The sagittal otoliths were first to appear, forming shortly before hatch and were observed growing larger throughout the larval stage.  The lapilli otoliths formed within the first 24 hours post hatch.  The asterisci otoliths were more difficult to locate but formed between 4 and 15 days post hatch.  At hatch the sagittae appear spherical but flattened laterally.  At 15 days post hatch the otoliths begin to elongate along the anterior/ posterior axis and the sulcus has formed.  This knowledge of the when the otoliths form will affect any microchemical analysis done on the first year of life.