Response to Environmental Factors of Spawning Ground in the Pearl River Estuary, China

Dongliang Wang,Lijun Yao,Ruirui Hu,Jing Yu,Pimao Chen

doi:10.3390/jmse9070763

Abstract

Spawning grounds are important areas for fish survival and reproduction, and play a key role in the supplement of fishery resources. This study investigated environmental effects on the spatiotemporal variability of spawning ground in the Pearl River Estuary (PRE), China, using the generalized additive model (GAM), based on satellite remote sensing (sea surface temperature (SST), chlorophyll-a concentration (Chl-a), sea surface salinity (SSS), depth), and in situ observations. Results showed that 39.8% of the total variation in fish egg density was explained by these factors. Among them, the most important factor was SST, accounting for 14.3%, followed by Depth, SSS, and Chl-a, with contributions of 9.7%, 8.5%, and 7.3%, respectively. Spawning grounds in the PRE were mainly distributed in the waters with SST of 22 °C, depth of 30–50 m, SSS of 16–35 ‰, and Chl-a of 6–15 mg/m3. From spring to summer, the spawning ground moved from the outlet of the PRE to the east. The distribution of the spawning ground in the PRE was mainly affected by the Pearl River Plume (PRP), Guangdong Coastal Current (GCC), and monsoons in this area.

Highlights

Spawning grounds are the areas where fish, shrimps, and shellfish mate, spawn, hatch, and breed, and are critical for the survival and reproduction of aquatic animals [1].Fish eggs, as an important biological group, are the foundation for the replenishment of fishery resources and sustainable utilization of fishery resources [2]
generalized additive model (GAM) Analysis In GAMs, the contribution of each selected factor to the egg density indicates the degree of influence of each factor on the egg density (Table 3)
The environmental effects of the spatiotemporal distribution of fish eggs were quantified in the Pearl River Estuary (PRE)

Summary

Introduction

Spawning grounds are the areas where fish, shrimps, and shellfish mate, spawn, hatch, and breed, and are critical for the survival and reproduction of aquatic animals [1].Fish eggs, as an important biological group, are the foundation for the replenishment of fishery resources and sustainable utilization of fishery resources [2]. It is of great significance to understand the distribution of fish eggs for maintaining the balance of marine ecosystems [3]. As a critical and vulnerable period in the life cycle of fish populations, the distribution of fish eggs is influenced by the spawning behavior of fish (including spawning locations, timing, etc.) and ocean dynamics phenomena (currents, eddies, upwelling and stratification of the water column, etc.) [4,5,6,7,8], and by water temperature, salinity, water depth, and topography [9,10,11]. Studies have shown that the timing of spawning population emergence in fish distributed in the English Channel was related to water temperature.

Methods

Results

Discussion

Conclusion