Qinghai Lake's naked carp population migrates annually in June and July when the adjoining rivers sometimes overflow with fish. The species is endemic to the lake and has adapted to brackish water, but when spawning season arrives, the adults migrate to nearby freshwater to procreate. When carp migrate, the current stimulates their gonads to maturity, which allows them to mate during the journey.

The naked carp plays a critical role in maintaining Qinghai Lake's ecological balance, so locals have constructed specialized "stair-steps" and a five-meter-long "resting area" on the riverbed of the Quanji River, one of the region's busiest migration channels.

Naked carp can grow to a maximum of 48 cm long, so disassembling the tall dam into multiple steps helps make their leap easier. The exhausted fish can also take a break in the resting area before continuing their journey upstream.

Monitoring equipment has been set up along the river to collect population data 24 hours a day, which are analyzed to deduce migration habits, population structure and the impact of the river's physical characteristics.

(Cover image via CFP)

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