Vocalization behavior differs across reproductive stages in cultured large yellow croaker Larimichthys crocea (Perciformes: Sciaenidae)

The large yellow croaker (Larimichthys crocea) is among the most important commercial aquaculture fish species in China. Although croakers are known to produce sounds, especially during the spawning season, the relationship between vocal behavior and spawning activity in this species remains largely unknown. In this study, sound production of cultured sexually mature L. crocea was monitored before and during the spawning periods. We estimated the spawning time of L. crocea by examining the embryonic development of fertilized eggs, and divided reproductive stages into four periods (T1-T4) based on the timing of hormonal treatment and spawning of L. crocea. A total of 1340 calls from four periods were analyzed to investigate the relationship between the call characteristics and the different spawning periods. The results demonstrated that L. crocea produced low-frequency pulsed sounds, and sound features differed significantly across reproductive stages in all four periods. During the spawning periods (T3 and T4), longer sounds were produced, with a higher number of pulses per call, a shorter pulse period, and a higher peak frequency than those produced before the spawning periods (T1 and T2). ‘Chorus’ calling was closely related to spawning activity. During the ‘chorus’ periods, the sound pressure level of soundscape in the tank increased by ~30 dB compared to prior no ‘chorus’ periods. Therefore, L. crocea vocalizations can be used as important indicators to determine spawning states and spawning time. We demonstrate that passive acoustic monitoring of L. crocea can provide information about the species spawning time, which will aid in improving both aquaculture management and discovery and protection of spawning habitats of wild L. crocea populations.