Rugulopteryx okamurae beachcast trends in Algiers beaches
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Date
2026-06-30
Authors
SID AHMED, Souad
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Publisher
ENSSMAL
Abstract
This thesis examines the invasion of Rugulopteryx okamurae along the beaches of Algiers using Sentinel-2 satellite imagery and the Google Earth Engine platform. The ethodology is based on six field surveys and the analysis of 258 satellite images acquired between 2023 and 2026.
The classification model achieved an overall accuracy of 70.25%. The results indicate a progressive expansion of the species, with the highest biomass accumulations observed at El Djamila and Sidi Fredj beaches. Seasonal dynamics revealed increased floating biomass during summer and higher beachcast accumulation in winter and autumn, emphasizing the role of hydrodynamic conditions in biomass distribution. This study provides the first large-scale assessment of R. okamurae dynamics in Algeria and highlights the effectiveness of remote sensing for monitoring invasive marine macroalgae and supporting coastal management.