[alcover]

Fascinating question.

Wildly speculating, I'd suppose european concubines were very much sought after by slavers and their 'customers'. And even more so blonds and redheads for their 'exotism'.

Now some Algerians look very european. You can even see redheads, though I remember redheadness appeared independantly in Europe and the Levant I think.

[inglor_cz]

The indigenous people of North Africa are Berbers, and many Berbers have lighter complexion and hair.

The same was true about the Guanche, who used to inhabit the Canary Islands before their Spanish conquest. They were "whiter" than the Spanish who conquered them.