Reproductive Capacity, and Production Characteristics of Fertilization Eggs in Second and Third Generation by Natural Spawning of Cultured Broodstock Small Yellow Croaker, Larimichthys polyactis

This study investigated the reproductive capacity of the 1st generation of cultured broodstock small yellow croaker, Larimichthys polyactis, and the characteristics of fertilized egg production through natural spawning of 2SUPnd/SUP and 3SUPrd/SUP generation broodstock. Matured ovaries for had a fair of asymmetric crystovarian structure. Cultured females broodstock grow faster than males at the same age, the relationship between body weight (BW) and total length (TL) of female was expressed as BW = 92.293TLSUP0.1378/SUP (r²=0.2324). The range for fecundity was 35,844~87,778 individuals (TL and BL of broodstock were 19.0~23.0 cm and 101.8~214.1 g, respectively) and gonadosomatic index (GSI) was 29.8~40.8. Natural spawning of cultured 2SUPnd/SUP generation broodstock (3 years old) was maintained for 18~33 days by different supplied feed type (extruded pellet combine with shrimp, grounded fish feed (control) and moist pellet). The highest floating rate (27.3%) was observed in the moist pellet feed group, while spawning volume (2,728 mL) was found in the shrimp feed group. Natural spawning of cultured 3rd generation broodstock (2 years old) was maintained for 40 days, and the spawning volume (4,466 mL) and floating rate (67.0%) were improved compared to those of 2SUPnd/SUP generation (3 years old). These results suggest that reproductive capacity of cultured small yellow croaker was better than that of wild stock and it was increased as the generation progresses with domestication.