Routine monitoring in the Maritime Provinces, Canada reveals novel records and range extensions for introduced red algal (Rhodophyta) species

The senior author has been studying seaweed diversity in the Maritime Provinces over the past 30 years. In recent years, ongoing baseline surveys have revealed novel species and range extensions into these coastal waters. The gradual creep of Bonnemaisonia hamifera Hariot and the first records for Antithamnion cf. sparsum Tokida, Dasysiphonia japonica (Yendo) H.-S.Kim, and Lomentaria orcadensis (Harvey) Collins in the Bay of Fundy are provided. Additionally, the first Canadian records for Bangia sp. 1Asia, Callithamnion debile Harvey, and Melanothamnus japonicus (Harvey) Díaz-Tapia & Maggs are presented. Further, the overlooked species Bangia sp. 4BAN was encountered for the third time in Atlantic Canada joining two previous records in the Bay of Fundy from 2010 (Nova Scotia side) and 2020 (New Brunswick side). Similarly, the presence of Melanothamnus cf. eastwoodiae (Setchell & N.L.Gardner) Díaz-Tapia & Maggs is confirmed in Atlantic Canada having been first encountered in 2022. Finally, Dasya elegans (G.Martens) C.Agardh (previously known as Dasya baillouviana (S.G.Gmelin) Montagne) is now recognized as an introduction to the Gulf of Saint Lawrence ca. 1960 and to the Bay of Fundy presumably at some point in the past few years.