GretagrundGretagrund is a shoal located a few km southeast of Ruhnu island in the Gulf of Riga, Estonia.Protected areaSince 12 August 2010 the water area was taken under protection as being a habitat for the following migratory birds: Black-throated loon, little gull, red-throated loon, long-tailed duck, velvet scoter and razorbill. During a survey in 2008, Paramysis intermedia was found in Gretagrund as a new species in the Baltic Sea.