Abstract

We report for the first time the occurrence of the Japanese kelp Saccharina japonica on the Pacific coast of southern Chile following an illegal introduction for aquaculture purposes. In November 2020, a citizen complaint indicated that the non-native kelp was being illegally farmed in Canal Caicae ' n. Specimens of the non-native kelp were collected during successive surveys for molecular and morphological analyses, and reproductive viability tests. The species was determined using two mitochondrial molecular markers, COI and trnW-L. Phylogenetic analysis confirmed the taxonomic identity of the specimen as S. japonica and revealed a genetic similarity with S. japonica x S. latissima hybrid cultivars Sanhai and Rongfu. In April 2021, several adult specimens became fertile at the farm site and the laboratory and released meiospores were able to develop into embryos after 15-20 days of incubation. These findings underline the risk for this kelp to disperse and colonize in the natural surrounding habitat, with potential impacts on local coastal ecosystems.