Larval Fish Assemblages and Distribution Patterns in the Zhongsha Atoll (Macclesfield Bank, South China Sea)

Delian Huang,Jing Chen,Zhaojin Lin,Feiyan Du,Yafang Li,Shuangshuang Liu,Lianggen Wang,Jiajia Ning,Lei Xu,Xuehui Wang

doi:10.3389/fmars.2021.787765

Delian Huang, Jing Chen + Show 8 more

Open Access

https://doi.org/10.3389/fmars.2021.787765

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Abstract

The remote coral reef in the deep sea is one of the most important nursery grounds for many marine fishes in the South China Sea. Diversity studies on larval fishes in this area are few, and the fish information on the coral reefs ecosystem is lacking. In this study, larval fishes were sampled during the summer of 2019 from the Zhongsha Atoll in the South China Sea and identified using DNA barcodes for the first time. Ninety-five larval fish species were recognized, belonging to 37 families and 12 orders based on morphological classification and DNA barcoding identification. The larval fish collected could be assigned to three categories as reef-associated, deep-sea, and pelagic. Most of the species were small fish with low commercial value but would play an essential role in the coral reef ecosystem. Some commercial fishes, including Auxis thazard, Euthynnus affinis, Sarda orientalis, Decapterus macarellus, Lutjanus viridis, and Centropyge vrolikii, were the dominant species higher than 2% total catch. The larval fish assemblage showed distinct spatial differences responding well with the geographical conditions. The most reef-associated fish occurred inside the Atoll, and the abyssal fish presented near the edge. In addition, larval fish spread over from the southwest to northeast may reflect the oceanography effect.

Highlights

Larval fish is the basis for the sustainable utilization of fishery resources, with survival directly influencing recruitment
445 larval fish were collected, 146 specimens were used for molecular experiments after morphological classification, and 12 samples failed in DNA extraction and PCR process
In face to the coral decline, understanding the present status of coral reef fishes in the South China Sea in terms of their biodiversity and abundance is essential for the sustainable protection and restoration of coral reef ecosystems (Jones et al, 2004; Brandl et al, 2019)

Summary

Introduction

Larval fish is the basis for the sustainable utilization of fishery resources, with survival directly influencing recruitment. Its investigations serve as an alternative approach for fish biodiversity, especially for some habitats, e.g., coral reefs and mangroves, where conventional fish sampling is challenging. The information on the distribution and abundance of larval fish provides a means to know the fish diversity, which is the base for fisheries management and conservation planning of the ecosystem (Almany et al, 2017). Coral reefs are among the most biologically diverse and valuable ecosystems, providing habitat for over 4,000 species of fish at some point in their life cycle (Teh et al, 2013; Woodhead et al, 2019), especially in the early growth stages. Living coral reefs play as spawning areas, hatchery yards, nursery grounds, and recruitment sites (Jones et al, 2005; Cole et al, 2008; Almany et al, 2017).

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