She shook her head. The problem this posed was great. The only real solution was to move them. Find a new home for the Merfolk. Which makes it incredibly hard to keep them from the open seas. Black Lake was among the largest lakes in the Highlands that Avalon covered. Not that Avalon had any jurisdiction over Hogwarts, but the lands were close enough and the pact I made with the Founders ensured their safety. The fact that it has been held all these years was a blessing. 