Though now a beach, but originally, it was a rocky shore where people carried sand to create a swimming area. This perhaps explains why you can see creatures that usually live on sandy beaches and those that usually live on rocky shores. For example, while there are animals which camouflage themselves in the sand, there are also those that camouflage themselves in the rocks. Also, if there you find uni or sea urchin rolling around in the sand, you are bound to find those clinging to the rocks too.