Recently, a new study shows that California's large-scale salmon, which adopts a rare late migration strategy, is more likely than similar populations to survive years of drought and marine heat waves. The findings show that as environmental conditions continue to change with climate change, conservation strategies are needed to maintain population diversity and ensure the long-term resilience of this endangered species. On October 28, the paper was published in Nature - Climate Change.
Population diversity is an important way for species to resist natural or man-made disturbances, including those brought about by climate change. Salmon migrate from freshwater to saltwater during their life cycle, and flexible migration times may be particularly important for this fish.
Flora Cordoleani of the National Oceanic and Atmospheric Administration and colleagues used the strontium isotope ratio of the ear bone of the spring-shaped large-scale salmon as a geo-marker, reconstructing the life history of 123 adult fish migrating to California's Central Valley from 2007 to 2018. These fish stay in the freshwater streams where they were born in the summer during the first winter or spring after birth, rather than migrating to the ocean. Studies have shown that this late migration strategy is critical for species to survive drought and ocean heatwave years.
Late migration requires suitable cool rivers, which are expected to decline rapidly in the coming years due to climate change, and most of which are located above dams that fish cannot cross. In light of this, the researchers note that habitat connectivity should be considered to maintain population diversity, which is important for the long-term survival of the species. (Tang Yichen)
Source: China Science Daily