Posidonia seagrass

The Posidonia oceanica meadows around Capo Testa are in exceptionally good health — a reflection of the low boat traffic, clean water, and geological substrate that the granite peninsula provides. The meadow acts as a nursery for juvenile grouper, sea bream, and cephalopods, and its dense leaf blades slow water movement, trapping sediment and keeping the water column clear. Dead leaf mats (matte) at the seagrass margin form hard substrate where nudibranchs and encrusting bryozoans flourish.