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Site of Special Scientific Interest (SSSI)

Sites of Special Scientific Interest (SSSI's) are areas that are protected for their  biological or geological features.


Aerial picture showing the SSSI boundary at Cosmeston LakesA SSSI is a conservation designation where some of the most important habitats, species and geological features can be found.  There are over 1,000 SSSI's in Wales covering more than 235 thousand hectares this is just over 12% of the country's land surface. 


SSSI's are protected by law against damage from development or damaging management practices.  

A SSSI's can vary dramatically in size, the smallest is a Lesser Horseshoe bat roost in Pembrokeshire at only 0.004ha the largest is the Berwyn mountain range with 24,321ha of moorland, heath, blanket mire and associated upland birds.


Cosmeston Lakes has 25.6ha designated as a SSSI to protect a rare plant called Starry stonewort (Nitellopsis obtuse).  Starry Stonewort prefers lakes between 1 and 6m deep at low altitudes in calcareous waters usually near to the coast, thus Cosmeston lakes are an ideal habitat. 


In the UK Starry Stonewort is classified as endangered and is also scarce throughout Europe. Habitat degradation water pollution and eutrophication particularly from phosphates and nitrates are some of the major factors causing loss or decline of the species. Find out more about SSSI's on the  Natural Resources Wales website.


Natural Resources Wales 



3D Video of East Lake

This video clip shows a 3D image of the East lake. The information was captured by Cardiff BSAC with their sonar Camera.


Depth in Metres:

  • White areas 9 Metres
  • Light blue 7.5 Metres
  • Dark blue 6 Metres
  • Green 4 metres
  • Yellow 3 Metres
  • Orange 1 Metre
  • Red less than 1 Metre