Nudibranch

Cathedral Rock's arch walls host a rich nudibranch fauna including the white-and-orange Limacia clavigera, which feeds on bryozoans coating the rock alongside jewel anemones. The sheltered nature of the arch interiors creates a microhabitat with reduced surge and lower light that favours slow-moving grazers. Spring through early summer brings the highest nudibranch diversity, with spawning aggregations of multiple species sometimes visible simultaneously on the same rock face.