When I first came to Malta in 1977, we British expatriates used to pay Lm2 to buy a turtle from the market at Marsaxlokk, just to place it back in the sea and try to save its life.
This was to no avail, of course, as the local fishermen just caught it again, to sell to restaurants to make turtle soup.
Now you are putting up posters warning about the jellyfish invasion, as Malta is now surrounded by them. Turtles feed on jellyfish, so if they had not all been fished out of the sea 30 years or so ago, this jellyfish problem would not exist, and the sea would be safe for all toswim in today.
Therefore, it would have been a good idea to listen to us at the time. Much as I enjoy living in Malta, I preferred it 34 years ago.