Out-of-season spawning of largemouth bass in a controllable recirculating system

Chen-Hao Hu; Han-Qing Bie; Zi-Yi Lu; Yang Ding; He-He Guan; Long-Hui Geng; Shuai Ma; Yuan-Xiang Hu; Qi-Xue Fan; Zhi-Gang Shen

doi:10.3389/fphys.2023.1175075

Out-of-season spawning of largemouth bass in a controllable recirculating system

Front Physiol. 2023 Apr 24:14:1175075. doi: 10.3389/fphys.2023.1175075. eCollection 2023.

Authors

Chen-Hao Hu¹, Han-Qing Bie¹, Zi-Yi Lu¹, Yang Ding¹, He-He Guan¹, Long-Hui Geng¹, Shuai Ma¹, Yuan-Xiang Hu¹, Qi-Xue Fan^{1

2}, Zhi-Gang Shen¹

Affiliations

¹ College of Fisheries, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture and Rural Affairs/Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Engineering Technology Research Center for Fish Breeding and Culture in Hubei Province/Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt of Ministry of Education, Huazhong Agricultural University, Wuhan, China.
² HuBei HuangYouYuan Fishery Development Limited Company, Wuhan, China.

Abstract

Largemouth bass (LMB) production exceeded 0.7 million tons in 2021 and has become one of the most important freshwater aquaculture species in China. The stable and fixed culture cycle led to regular and drastic price fluctuation during the past decade. Strong price fluctuation provides opportunities and challenges for the LMB industry, and out-of-season spawning (OSS) and culture will provide technical support for the opportunities. To induce OSS at a low cost, we established a controllable recirculating system that allows precise thermo-photoperiod manipulation. In the system, four experimental groups were assigned, 18NP (18°C overwintering water temperature, natural photoperiod), 18CP (18°C overwintering water temperature, controlled photoperiod), 16CP (16°C overwintering water temperature, controlled photoperiod), and NTNP (natural water temperature and natural photoperiod), to determine the effects of chilling temperature and photoperiod on spawning performance. OSS was observed in all the experimental groups without significant differences, except NTNP. The manipulated broodstock can re-spawn 3 months later in the next spring in advance. Further analysis of the volume percentage of different stages of oocytes provides a base for excellent regression between the volume percentage of the primary growth stage, cortical alveoli stage, vitellogenesis/maturation stage, and gonadal development/maturation. The results suggest that the volume percentage of oocytes is a better indicator of gonadal development and maturation than the gonadosomatic index. We also found that LMB prefers palm fiber as a spawning nest over gravel. The findings of this work provide important technique guidance for practical OSS of the LMB aquaculture industry and standardization of ovary development and maturation in fish with asynchronous developmental oocytes.

Keywords: energy allocation; largemouth bass; out-of-season spawning; ovary development; recirculating system.

Grants and funding

This research was supported by the National Natural Science Foundation of China (32273122) and Fundamental Research Funds for the Central Universities (2662021SCPY001).