In a saucepan, combine all the ingredients. Bring to a boil. Cook for about 10 minutes or until a candy thermometer reads 116 °C (240 °F), stirring occasionally.
Remove from the heat and let cool.
Lightly butter a marble slab or line a baking sheet with parchment paper.
For each turtle, place a few pieces of pecans, the equivalent of 1 whole nut, on the baking sheet.
With two spoons, spread approximately 7.5 ml (1 1/2 teaspoons) of caramel over each serving of pecans. Gently reheat the caramel along the way, if necessary. Let cool completely.
In a double boiler, melt half the chocolate. Remove from the double boiler.
Peel half of the turtles off the slab or parchment paper, then dip them, one by one, into the melted chocolate, holding them between two forks. Melt the remaining chocolate and repeat with the remaining turtles. Place on parchment paper and let stand overnight.