Rapid expansion of the invasive‐like red macroalga, Chondria tumulosa (Rhodophyta), on the coral reefs of the Papahānaumokuākea Marine National Monument

A rapid and exponential expansion of the invasive-like red macroalga, Chondria tumulosa, has been observed on the coral reefs of Manawai Atoll within Papahānaumokuākea Marine National Monument. Initially detected in 2016 forming dense mats on the forereef, this alga exhibited a dramatic increase in abundance over five years. By 2021, unattached C. tumulosa formed extensive dark accumulations spanning 41.32 km in length and covering 101.34 km² in area, marking a 56-fold and 115-fold increase from its first detection, respectively. High-resolution satellite imagery revealed an exponential expansion rate of approximately 16.02 km per year in length and 44.75 km² per year in area. This study provides a comprehensive temporal and spatial analysis of the alga's spread since its discovery, offering critical data for ecologists and resource managers to monitor its invasive-like behavior.

Lopes, K. H., Miura, T., Hauk, B., Kosaki, R., Leonard, J., & Hunter, C. (2023). Rapid expansion of the invasive‐like red macroalga, Chondria tumulosa (Rhodophyta), on the coral reefs of the Papahānaumokuākea Marine National Monument. Journal of Phycology, 59(5), 1107–1111. Portico. https://doi.org/10.1111/jpy.13369