MIERA RIVER MOUTH
(RIA DEL CUBAS)
After its source, the Miera River runs placidly for 41 km through a glacial valley between narrow gorges, crossing small towns such as Liérganes or Mirones and other larger towns such as Solares, until it reaches its mouth in the Cubas estuary. Shortly before its mouth in the Bay of Santander through the Ría de Cubas, the Miera River receives the contributions of the Pontejos River
It is precisely this last section known as the Ría de Cubas (the one that runs through the municipalities of Ribamontán al Mar and Marina de Cudeyo), the area with the greatest ecological value and the protected area belonging to the LIC litoral de las Dunas del Puntal.
From its seabed we highlight the meadows of Zosfera Marina , a plant with many possibilities and that definitely contributes against climate change.
In turn, this is the area of the entire river route that receives the most pressure due to the high degree of livestock and industrial activity that takes place in its flood plains.
The estuary presents wide intertidal zones, occupied by sandbanks and muds on which Zostera seagrass meadows develop and halophilic scrubs of Spartina sp, Salicornia sp, Halimione portulacoides and Juncus sp., among other species.
In the Cubas estuary, a project is being developed to recover the "Fishing Eagle", a bird that appears in the category of «Vulnerable» in the National Catalog of Threatened Species and in «Critical Danger» in the Red Book of Birds of Spain.