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.

Automated summary

The study provides a detailed staging system for hatchery-reared sunshine bass larvae, identifying a biphasic pattern of larval growth and demonstrating that age and standard length are good predictors of larval stage.