Invasion status of hatchery‐origin pink salmon in an unstocked river at the Shiretoko World Natural Heritage Site in northern Japan

Research at the Shiretoko World Natural Heritage Site reveals significant invasion of hatchery-origin pink salmon (Oncorhynchus gorbuscha) into unstocked rivers, with strays comprising 40.0% and 19.0% of samples in 2021 and 2022, respectively. This finding underscores the potential genetic impact on wild populations, as hatchery fish and their hybrids exhibit lower reproductive success than wild counterparts. The study highlights the need for caution regarding straying rates, particularly for species like pink salmon with higher propensity to disperse beyond stocked areas. Investigators analyzed samples to quantify hatchery-origin fish, providing critical data for conservation efforts in pristine environments.

Yamada, T., Nobetsu, T., Urabe, H., & Nakamura, F. (2024). Invasion status of hatchery‐origin pink salmon in an unstocked river at the Shiretoko World Natural Heritage Site in northern Japan. Journal of Fish Biology, 104(5), 1633–1637. Portico. https://doi.org/10.1111/jfb.15690