Larval development staging table for hatchery-reared sunshine bass (Morone chrysops♀ x Morone saxatilis♂)

Aquaculture of hybrid Morone species is preferred over that of purebred strains due to their higher growth rates and resilience to a wide range of rearing conditions. One of the most popular hybrids is the sunshine bass, which is a cross between white bass (M. chrysops) females and striped bass (M. saxatilis) males. Yet, despite their growing economic importance, a detailed description of sunshine bass larval development under captive conditions is missing. Here, we provide a detailed staging system of hatchery-reared sunshine bass larvae. Based on externally visible features, we define 15 distinct stages from hatching to juvenile stage (2–43 days post-fertilization). We identified a biphasic pattern of larval growth, with a 2-fold increase in growth rates (from 0.2 to 0.4 mm/day) around the onset of metamorphosis and larger variations in length and weight after the completion of metamorphosis. Both age (R² = 0.93) and standard length (R² = 0.89) were good predictors of larval stage. Overall, this work provides a reference for studies of factors that affect sunshine bass larval development and, thus, is an important step towards resolving bottlenecks in larval rearing operations in this species.