摘要Objective: To monitor the distribution of Cymodocea nodosa (Ucria) Ascherson in Las Canteras Beach (Las Palmas de Gran Canaria, Spain), comparing the status in 2005 with the distribution observed in 1985 and 1995. Methods: Field observations by selfcontained underwater breathing apparatus diving records and cartographic report.Results:rocks, which sheltered it from the strong north-east winds and swells. Since 1985 a gradual reduction of its extent has been observed and more than 80% of the original canopy disappeared in twenty years time, mostly due to the anthropogenic impact and modification of the sedimentary dynamics of the beach.Conclusions:Conclusions: The degradation of this seagrass meadow determinates the loss of the only meadow in the north of the island of Gran Canaria and the absence of a management plan for its conservation.