Transcriptomic Analysis on the Effects of Altered Water Temperature Regime on the Fish Ovarian Development of Coreius guichenoti under the Impact of River Damming

Abstract

Field investigation indicated that the reduction in fish spawning was associated with the alteration in water temperatures, even a 2–3 °C monthly difference due to reservoir operations. However, the physiological mechanism that influences the development of fish ovary (DFO) remains unclear. Thus, experiments of Coreius guichenoti were conducted at three different temperatures, optimal temperature (~20 °C, N) for fish spawning, lower (~17 °C, L), and higher (~23 °C, H), to reveal the effects of altered water temperature on the DFO. Comparisons were made between the L and N (LvsN) conditions and H and N (HvsN) conditions. Transcriptomic analysis differentially expressed transcripts (DETs) related to heat stress were observed only in LvsN conditions, indicating that the DFO showed a stronger response to changes in LvsN than in HvsN conditions. Upregulation of DETs of vitellogenin receptors in N temperature showed that normal temperature was conducive to vitellogenin entry into the oocytes. Other temperature-sensitive DETs, including microtubule, kinesin, dynein, and actin, were closely associated with cell division and material transport. LvsN significantly impacted cell division and nutrient accumulation in the yolk, whereas HvsN only influenced cell division. Our results highlight the impact of altered water temperature on the DFO, thereby providing insights for future reservoir operations regarding river damming and climate change and establishing fish conservation measures.

River Damming Impacts on Fish Habitat and Associated Conservation Measures

“…Tao et al, 2020), which delays the timing for reaching CTT and advances the timing for reaching the ATT (T. . It has been shown that elevated temperatures of 2-3°C in winter can have a significant impact on the development of fish gonads (T. M. Farmer et al, 2015;T. Li et al, 2022).…”

“…Operation of large reservoirs results in cooling in spring and summer, and warming in autumn and winter (Long et al., 2019; Y. Tao et al., 2020), which delays the timing for reaching CTT and advances the timing for reaching the ATT (T. Li et al., 2021). It has been shown that elevated temperatures of 2–3°C in winter can have a significant impact on the development of fish gonads (T. M. Farmer et al., 2015; T. Li et al., 2022). When the time to reach the ATT is advanced, fish tend to consume energy in the yolk in order to maintain early exercise and strengthen metabolism (Mcqueen & Marshall, 2017; Wright et al., 2017).…”