Öz The “First International Conference on the Mediterranean Monk Seal, Rhodes, Greece, 2-5 May, 1978” revealed that monk seal, Monachus monachus populatious disappeared on the west Mediterranean coastlines of Enrope, but stili they Iry to live on the coastline of Turkey and Greece in eastern Mediterranean, and if they are not protected properly soon they will be extinct in a few decates, but unfortunately there were no sound ecological or biological infor- matiou on their lifehistory t o begin to protect them soon. From 1980 onward3 being supported by the University of Ankara we have been carried on researches on this subject. We have already obtained almost enongh biological Information needed for protection, but with two exceptions; The exact localities of suitable breeding caves and the length of distance needed between two protected area to prevent the inbreeding and degenerations of the protected popnlation. By inquiring the small Coastal fishermen and veryfying the obtained Information in the place and finally taking detailed notes, we tried to visit nearly ali Turkish coastlines as many times as possible in order to compare the events with each others. Thus we could find out the longest distance monk seals could cover per year as 600-700 km. Ve discussed and evaluated the biological effects and results of this length for a succesful monk seal protection.