Data on snail coverage in a mesocosm experiment in the Oslofjord June to September 2022

<p><span>In August and September 2022, we measured <em>Littorina</em> sp. coverage on step 2 (the lower intertidal) in each basin. Coverage was visually identified as presence or absence in each of 16 5x5cm large cells within a 20x20 cm frame. Three frames were randomly placed within the seaweed patches and three in the seaweed-free corridors outside of the patches. Coverage was estimated as the percent of all 16 cells in the frames having <em>Littorina</em> sp. presence. </span></p>