Cascading fishery collapse associated with thermal habitat degradation, marine heatwaves, and predator influx

Global climate change and intensifying marine heatwaves contribute to abrupt fishery collapses. We investigate the fishery collapse of the Japanese flying squid (Todarodes pacificus) in the East Sea (Sea of Japan), which provides an early warning for climate-driven species replacements in warming oceans. Using multi-decadal observations (1993–2025), we identify a teleconnection where an intensified early-summer La Niña amplifies autumn–winter marine heatwaves within major fishing grounds. Sequential mediation analysis reveals that rising ocean temperatures drive the squid collapse through three interconnected pathways: gradual habitat degradation from long-term warming, acute thermal stress from marine heatwaves, and an ecological trade-off linked to the rapid influx of a warm-adapted predator (Seriola quinqueradiata). Climate model projections indicate unabated warming will increase the risk of the regional squid fishery reaching a zero-catch state by the 2040 s across multiple emissions scenarios. These findings underscore the urgent need for transboundary, climate-adaptive management. Early-summer La Niña conditions amplify marine heatwaves that are contributing to the collapse of the Japanese flying squid fishery and increasing the risk of a zero-catch state by the 2040 s, according to multi-decadal observations and climate projections.