Seasonal variations in diversity and abundance of surface ichthyoplankton in the northern South China Sea

Abstract

The objective of this study was to investigate the seasonal variations of ichthyoplankton diversity and abundance in the northern South China Sea based on the data collected during summer, winter and spring. In total, 95 taxa of larval fishes were identified. The greatest number of species was recorded in spring, followed by summer and winter. The number of species was distributed mainly in the coastal waters from the east of Leizhou Peninsula to the southeast of Hainan Island during the surveyed periods of summer and spring, but in the offshore waters during winter. The abundance of larval fish was lowest in winter, increased in spring, and reached the maximum in summer. High abundance of larval fish was generally restricted to coastal waters with the isobaths less than 50 m. Seasonal variations of larval fish richness, abundance and diversity index were significant (P<0.001). Carangidae was the most common and abundant taxon in summer and winter, while Sardinella sp., Thrissa mystax and Leiognathus sp. were dominant in spring. High diversity and abundance of larval fish might be attributed to increased temperature and coastal upwelling in spring and summer.

Plankton community of trafficked ports as a baseline reference for Non Indigenous Species arrivals. Case study of the Port of Bar (South Adriatic Sea)

“…Despite the low intensity and unfavourable conditions for spawning (different sources of pollution, noise and disturbance of the seafloor due to anchoring, as well as other port activities), there were still a significant number of different fish species found during the survey. The seasonal pattern of abundance and diversity of ichthyoplankton is consistent with the occurrence of seasonality in other (non-port) seas (Li et al, 2014). What is very interesting is the occurrence of the larval stages of Sparisoma cretense.…”

Identification of Eggs and Spawning Zones of Hairtail Fishes Trichiurus (Pisces: Trichiuridae) in Northern South China Sea, Using DNA Barcoding

“…Recent progress in understanding the reproductive biology and fishery ecology of these economic fishes has been made (Zhang et al, 1985;Chen et al, 2003;Yan et al, 2011;Shi et al, 2020). However, due to the difficulties identifying early life stages of fish, information of their spawning grounds based on ichthyoplankton surveys is limited in the SCS (Zhang et al, 1985;Zhou et al, 2011;Li et al, 2014;Chen et al, 2018).…”

Assemblage Structure of the Ichthyoplankton and Its Relationship With Environmental Factors in Spring and Autumn off the Pearl River Estuary

“…This suggests that many fish species spawn in both spring and autumn. Most species also have spawning peaks in spring, which corresponds to subtropical monsoon characteristics in the northern SCS and adjacent waters (Tzeng et al, 2002;Hsieh et al, 2005;Hsieh H. Y. et al, 2010;Xiao et al, 2013;Li K. Z. et al, 2014). Earlier analyses of fish spawning times were based largely on monitoring gonad development of fishes in the northern SCS (i.e., begin at gonadal maturity stage IV); such an approach is also expensive and requires considerable manpower and logistical resources (Chen et al, 2002(Chen et al, , 2003.…”

“…Precise identification of species in ichthyoplankton samples is important to understand species reproductive biology, preferred spawning time, and spawning grounds (Baumgartner et al, 2004;Cao et al, 2007;Claydon et al, 2014;Zhang et al, 2015). However, accurately identifying fish eggs and larvae to species is difficult, probably for which reason there have been few empirical studies on ichthyoplankton in the SCS (Li K. Z. et al, 2014;Huang et al, 2017;Hou et al, 2021). DNA barcode, which delimits species using molecular maker (e.g., cytochrome c oxidase subunit I, COI), have been widely applied to facilitate the identification of fish eggs and larvae (Valdez-Moreno et al, 2010;Frantine-Silva et al, 2015;Hubert et al, 2015;Leyva-Cruz et al, 2016;Burrows et al, 2018;Kerr et al, 2020;Chen et al, 2021;Hou et al, 2021).…”