From PathfinderWiki

The Bloodpools are a series of caves that lie within the underground district of the Knotworks in the pirate city of Port Peril. The Bloodpools are filled with all manner of exotic sea urchins and it is believed that the depths of the Bloodpools holds some sort of connection to the seas of the surrounding Jeopardy Bay. It is perhaps due to this clandestine connection to the sea that visitors sometimes report seeing merfolk and other, stranger creatures within the Bloodpools' depths.1