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How is Freshwater Fish Reproduction Affected From Changing Climatic Patterns

Manish Devkota, Hemraj Kathayat, Theingi Nan Soe

There are multiple literatures with evidence of changing climatic pattern and their effect on the freshwater ecosystem. The habitat within it is highly vulnerable to these changes because many species have limited abilities to get dispersed with the changing environment. Specifically, “what are the impacts and upshot of global climate pattern shift on the freshwater fish reproductive physiology and phenology?” is the interesting question to seek. Notable observations have been made in temperatures, hypoxia, and hydrology regimes, presumably affecting spawning (timing, pattern, and habitats), endocrine (HPG) axis, sexual maturation, gamete formation, sex differentiation, embryonic development, and hatching. Phenological changes are primarily driven by abrupt fluctuations in temperature - increasing temperature along with hypoxia disrupts the endocrine and brings reproductive impairment. Freshwater fish respond to changing climatic patterns by shifting their distribution range, changing migration times, and spawning. Similarly, Temperature-Dependent Sex Differentiation (TSD) species are more affected and the effect is projected to increase in the near future. In the meantime, there are several concerns regarding the harm to freshwater fish, either due to changes in climate trends or due to anthropogenic activities, but there is growing evidence of the impact of change in climatic patterns on the reproduction, development, structure, and abundance of freshwater fish populations.