GnIH

Fish experiencing abnormally high or prolonged elevations in temperature can exhibit impaired reproduction, even for species adapted to warm water environments. Such high temperature inhibition of reproduction has been linked to diminished gonadal steroidogenesis, but the mechanisms whereby hypothalamic-pituitary-gonadal (HPG) axis signaling is impacted by high temperature are not fully understood.
Elsevier, General and Comparative Endocrinology, Volume 157, July 2008
All organisms respond to environmental cues that allow them to organize the timing and duration of life history stages that make up their life cycles. Superimposed on this predictable life cycle are unpredictable events that have the potential to be stressful. Environmental and social stresses have deleterious effects on life history stages such as migration, reproductive function and molt in vertebrates. Global climate change, human disturbance and endocrine disruption from pollutants are increasingly likely to pose additional stresses that could have a major impact on organisms.