Journal of Marine Science and Engineering Article Small Jellyfish as a Supplementary Autumnal Food Source for Juvenile Chaetognaths in Sanya Bay, China Lingli Wang 1,2,3, Minglan Guo 1,3, Tao Li 1,3,4, Hui Huang 1,3,4,5, Sheng Liu 1,3,* and Simin Hu 1,3,* 1 CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;
[email protected] (L.W.);
[email protected] (M.G.);
[email protected] (T.L.);
[email protected] (H.H.) 2 College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China 3 Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 510301, China 4 Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences, Sanya 572000, China 5 Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya 572000, China * Correspondence:
[email protected] (S.L.);
[email protected] (S.H.) Received: 10 October 2020; Accepted: 19 November 2020; Published: 24 November 2020 Abstract: Information on the in situ diet of juvenile chaetognaths is critical for understanding the population recruitment of chaetognaths and their functional roles in marine food web. In this study, a molecular method based on PCR amplification targeted on 18S rDNA was applied to investigate the diet composition of juvenile Flaccisagitta enflata collected in summer and autumn in Sanya Bay, China. Diverse diet species were detected in the gut contents of juvenile F.