Evaluation of Fish Communities in Daya Bay Using Biomass Size Spectrum and ABC Curve

Shannan Xu,Yong Liu,Jianzhong Guo,Yayuan Xiao,Youwei Xu,Chunhou Li,Jiangtao Fan,Bahram Barati

doi:10.3389/fenvs.2021.663169

Abstract

Based on the data collected by four trawl surveys during 2016–2017, we applied biomass size spectrum (BSS) and abundance–biomass comparison (ABC) curve to assess the status of fish communities’ status in Daya Bay, China. Our findings indicated a unimodal pattern and biomass size ranged from −2 to 10 grain levels and the pattern of the Sheldon-type BSS of fish in Daya Bay. Moreover, fishes in the range of four to eight size class were relatively abundant. The highest peak belonged to the two to four grain level (log2 size bins), mainly consisting of Leiognathus brevirostris, Callionymus meridionalis, Callionymus koreanus, Evynnis cardinalis, Trachurus japonicus, and other small fishes. The curves of the BSS in spring and winter were relatively flat and comprised a large curvature. The summer and autumn curves were comparatively steep, and the seasonal curvature was small. The curvatures of the curve were mainly related to a large number of small Evynnis cardinalis and a small number of large-sized Harpadon nehereus and Leiognathus ruconius. In our study, it was observed that the number and the size of the breeding population, trophic levels, migration habits, and other life history characteristics, as well as anthropogenic disturbances (especially overfishing), significantly affected the peak shape, slope, or curvature of the fish BSS, with overfishing being the main factor. The ABC curve exhibited that Daya Bay was in a critical state of disturbance throughout the year. The spring, summer, and autumn were in severe disturbance, while the winter was in moderate disturbance.

Highlights

Understanding how fish communities respond to natural disturbances is fundamental to assess ecosystem resistance and resilience mechanisms (Romero et al, 2020)
Eleven stations were set in Daya Bay, among which the coast consists of five stations, namely, S1, S2, S3, S6, and S9; the middle of the bay consists of four stations, including S4, S5, S7, and S8; and the mouth of the bay comprises two stations, namely, S10 and S11 (Figure 1)
The fish community mainly composed of Evynnis cardinalis and Callionymus richardsoni, which feed on benthic organisms; Trachurus japonicus and Apogon lineatus, which feed on plankton organisms; and Leiognathus brevirostris and Clupanodon punctatus larvae, which feed on plankton and benthic organisms

Summary

Introduction

Understanding how fish communities respond to natural disturbances is fundamental to assess ecosystem resistance and resilience mechanisms (Romero et al, 2020). Changes in the fish size influence the ecosystem (Peterson and Wroblewski 1984; Scharf et al, 2000; Woodward et al, 2005). The ecological and biological characteristics of fishes can be determined according to their size. Fishes throughout their life cycle traverse a few trophic levels that are. Fish Community Evaluation in Daya Bay positively associated with their size (Jennings et al, 2001). The size spectrum is extensively applied to study the characteristics of the fish community, in the aspects of production and abundance (Sheldon et al, 1977; Boudreau and Dickie 1992; Cyr and Peters 1996)

Methods

Results

Discussion

Conclusion