Abstract
We investigated the invasion status of alien lineage of the Pond loach, Misgurnus anguillicaudatus in central eastern Kagawa Prefecture using genetic and morphological approaches. Genetic analyses based on mitochondrial DNA (mtDNA) revealed the invasion of a Chinese lineage at four of the five sites, while the Japanese lineage was restricted to one of the sites. Morphometric characteristics, including the number of branched soft rays of the dorsal fin and caudal peduncle length, exhibited distinct trends between the two lineages. As alien loaches have been introduced for fish farming, they may have spread along major rivers within the prefecture. Accurate lineage identification in future surveys is crucial for the conservation of the native lineage of M. anguillicaudatus.
