Marine seaweeds restoration, afforestation, and cultivation projects are fundamental for mitigating the impacts of global warming and for re-establishing ecosystem services in coastal marine environments. In this context, understanding the phenology and carrying capacity of natural beds, which are potential sources of donor matrices, constitutes the first step in implementing these projects. In this study, the phenology of Sargassum filipendula – a species that forms extensive beds in Southern Brazil – was monitored over one year through monthly collections at three sampling stations in the North Bay of Santa Catarina Island: Ratones Grande Island (RGI), Ponta do Sambaqui Beach (PS) and Sambaqui Médio Beach (SM). In addition to phenology, the recovery of a natural S. filipendula bed was also evaluated following the collection of matrices used for laboratory reproduction of the species. The S. filipendula bed was assessed before, immediately after, 2 and 4 months after the collection of matrices, considering the following parameters: number of individuals per m², fresh weight per m², fresh weight of mature fertile branches per m², and reproductive effort. All collections for this study were performed by sectioning the fronds (the annual portion of the thallus) at 3 ± 1 cm above the holdfast (the perennial portion of the thallus) to allow for regrowth and recovery of the sampled bed. Partial results can be viewed in Tables I and II (below). This work is expected to contribute to the development of marine forest restoration, afforestation, and cultivation projects in the Southern Brazil region.