Temporal Patterns of Larval Fish Occurrence in a Large Subtropical River

Abstract

Knowledge of temporal patterns of larval fish occurrence is limited in south China, despite its ecological importance. This research examines the annual and seasonal patterns of fish larval presence in the large subtropical Pearl River. Data is based on samples collected every two days, from 2006 to 2013. In total, 45 taxa representing 13 families and eight orders were sampled. The dominant larval family was Cyprinidae, accounting for 27 taxa. Squaliobarbus curriculus was the most abundant species, followed by Megalobrama terminalis, Xenocypris davidi, Cirrhinus molitorella, Hemiculter leuscisculus and Squalidus argentatus. Fish larvae abundances varied significantly throughout the seasons (multivariate analyses: Cluster, SIMPROF and ANOSIM). The greatest numbers occurred between May and September, peaking from June through August, which corresponds to the reproductive season. In this study, redundancy analysis was used to describe the relationship between fish larval abundance and associated environmental factors. Mean water temperature, river discharge, atmospheric pressure, maximum temperature and precipitation play important roles in larval occurrence patterns. According to seasonal variations, fish larvae occurrence is mainly affected by water temperature. It was also noted that the occurrence of Salanx reevesii and Cyprinus carpio larvae is associated with higher dissolved oxygen (DO) concentrations, higher atmospheric pressure and lower water temperatures which occur in the spring. On the other hand, M. terminalis, X. davidi, and C. molitorella are associated with high precipitation, high river discharge, low atmospheric pressure and low DO concentrations which featured during the summer months. S. curriculus also peaks in the summer and is associated with peak water temperatures and minimum NH3–N concentrations. Rhinogobius giurinus occur when higher atmospheric pressure, lower precipitation and lower river discharges occur in the autumn. Dominant fish species stagger their spawning period to avoid intraspecific competition for food resources during early life stages; a coexistence strategy to some extent. This research outlines the environmental requirements for successful spawning for different fish species. Understanding processes such as those outlined in this research paper is the basis of conservation of fish community diversity which is a critical resource to a successful sustainable fishery in the Pearl River.

Patterns of larval fish assemblages along the direction of freshwater input within the southern branch of the Yangtze Estuary, China: implications for conservation

“…Such seasonal peaks in abundance and number of species of larval fish were also observed in the lower Yangtze River (Ren et al 2016). The timing of reproduction is critical for a fish species to obtain optimal environmental conditions for offspring survival (Yin 2003;Shuai et al 2016). Zooplankton is the major food for most fish species during the larval stage as observed in fishes of the Yangtze River (Zhu 1987;Zhang et al 2002;Li et al 2014) and other water systems (Barletta-Bergan et al 2002;Koutrakis et al 2004;Winder and Jassby 2011).…”

“…Patterns of larval fish assemblages reflect the spawning and nursery functions of an estuary for fish (Strydom 2015;Teodosio and Garel 2015;Jiang et al 2016). Various biotic or abiotic factors, such as zooplankton abundance, water temperature, salinity, and water runoff influence larval fish assemblages in estuaries (Cao et al 2007;Shuai et al 2016;Zhang et al 2016). The sensitivity of ichthyoplankton to environmental factors potentially makes larval fish assemblages an important resource for understanding the key factors that determine the spatial and temporal patterns of habitat use, which may contribute to efficient conservation practices (Cao et al 2007;Able et al 2010;Primo et al 2011).…”

Composition and Abundance of Drifting Fish Eggs on the Upper Reaches of Xijiang River, China, after the Formation of the Cascade Reservoirs

“…Temperature strongly influences the dynamics of fish populations [28], by stimulating the gonads [29] and affecting spawning frequency [30]. Furthermore, flood pulses trigger spawning, especially for fish with drifting eggs [12, 31, 32]. Longer flood durations and greater flow discharge enhance fish production [33].…”

Distribution of economically important fish larvae (Characiformes, Prochilodontidae) in the Central Amazonia, Brazil

“…Such temporal patterns need to be understood to provide reliable evaluation of fish status and accurate basis for planning, and ensure healthy, well‐managed fisheries (Booth, ; Shuai et al., ). However, in the Amazon, studies of ecology and distribution the fish larvae remain scarce; exceptions are the studies of Oliveira and Araújo‐Lima (), Oliveira (), Araújo‐Lima, Silva, Petry, Oliveira and Moura (), Lima and Araújo‐Lima (), Oliveira and Ferreira (), Mounic‐Silva and Leite (), Ponte et al.…”

“…Such temporal patterns need to be understood to provide reliable evaluation of fish status and accurate basis for planning, and ensure healthy, well-managed fisheries (Booth, 2000;Shuai et al, 2016).…”