It seems clear that they have lived peacefully with other "normal" humans for generations.

zoomed out shot of glossy Selkie in scuba gear, varied expressions and poses, perfect eyes, scared; tetradic colors, waxy, detailed, futuristic, photorealistic, maximalist; Makoto Shinkai, J.C. Leyendecker, ilya Kuvshinov, Royo, Karol Bak, Alphonse Mucha, Jordan Grimmer, Greg Rutkowski

ugly, tiling, poorly drawn hands, poorly drawn feet, poorly drawn face, out of frame, extra limbs, disfigured, deformed, body out of frame, blurry, bad anatomy, blurred, watermark, grainy, signature, cut off, draft