Spawning of Schizopygopsis microcephalus (Cyprinidae) in the unique
high-altitude conditions of the Tanggula mountains on the Tibetan
Schizothoracine fish spawning habitats in the Tibetan Plateau are poorly
understood but critical for conservation amidst anthropogenic threats
and climate change. In a 2019–2021 study, we located the spawning
grounds of Schizopygopsis microcephalus Herzenstein, 1891, at an
astounding 4800 m above sea level, the highest known fish spawning site.
This occurred in mid-June, before seasonal flooding. We found
approximately six circular egg burial nests per square meter, measuring
20–30 cm in diameter and 10–15 cm deep, nestled within gravel (4–5 cm
max diameter, D50 of 2.2 cm). Egg fertilization rates reached 98%, with
an 82% hatching rate. Intriguingly, eggs displayed delayed shell
hardening during natural incubation, possibly to protect against intense
high-elevation ultraviolet radiation. Further investigations are needed
to understand the role of the pliable membrane. Survival of the species
requires that this kind of rare habitat be conserved.