Life-history habitat suitability modelling of a potential invasive alien species, smallmouth bass (Micropterus dolomieu), in South Korea

The aim of this study was to predict the distribution of a potential invasive alien species, smallmouth bass (Micropterus dolomieu), in South Korea using a life-history-based habitat suitability model. Environmental data (air temperature, water temperature, and fish occurrence) at present (2011-2020) were collected from 160 representative sites across the five river basins (Han, Nakdong, Guem, Seomjin, and Yeongsan). Future predictions were conducted under the representative concentration pathway 8.5 scenario in the 2050s (2046-2055) and the 2080s (2076-2085). Two spawning scenarios were implemented in the future, where smallmouth bass will not change the spawning season in the non-adaptive scenario and change the season in the adaptive scenario. The life-history habitat suitability (LHS) of smallmouth bass was evaluated using the geometric mean of the annual habitat suitability indices (HSIs) for each life stage (adult, juvenile, fry, and spawner). The LHS model was validated using the occurrence data of largemouth bass (Micropterus salmoides), which shares most of its habitats with smallmouth bass. The average LHS of smallmouth bass in South Korea was predicted to be 0.519 at present and expected to be 0.491 and 0.541 in the 2080s under non-adaptive and adaptive scenarios, respectively. Considering that the period for spawner fish may change in the future under climate change, the adaptive scenario seems to be more reasonable. The potential presence rate of smallmouth bass in South Korea was 100% at present, except for the Han River Basin (66%) which was expected to increase to 86% in the 2080s under the adaptive scenarios. The LHS model predicted that smallmouth bass could inhabit South Korea, and its distribution may expand under global warming, requiring urgent preventive measures.