I believe there is only one species of seal in the Mediterranean - the Mediterranean Monk Seal. The males are about the same size as male sea lions but the females are much larger than female sea lions (Seal male = 315kilo, 2.4m/sea lion male = 300kilo,2.4m; seal female 300kilo, 2.4m/sea lion female 100kilo, 1.8m). So it is far more likely to have been seals than sea lions - which live in the Pacific Ocean and parts of the Southern Atlantic. However, there are reckoned to be less than 700 individual seals left in the Med so if they were a Monk seals then a sighting of a couple would be a very rare event.
Well worth contacting a Turkish wildlife organization with your video to see if they verify this exceptional sighting.