Populations of gorgonian and other benthic organisms in the Natural Park of Cap de Creus and Natural Park in Montgrí experienced a high mortality rate during 2017 due the proliferation of filament algae in the Catalan coast during 2017. This phenomenon could be the result of the high temperatures in spring and summer and the high concentration of nutrients in the environment, according to a report on the monitoring of the marine environment in the Natural Park of Cap de Creus and the Natural Park in Montgrí, Medes Islands and Baix Ter in Catalonia (Spain).