For one the Moors were not apart of the Arab slave trade which was limited to Southeast Africa/Zanj's of Eastern Africa.
The Moors on the other hand were apart of the Trans Sahara trade like I stated to
@BlackFruitPunch. The Moors would have been limited to Northwest Africa. During the Moorish people they wouldn't be able to just steam roll right in and take slaves of their choosing. There was powerful Sahelian kingdoms/empires like Ghana and Mali acting as buffer zones against foreigners wanting to expand further south. The reason for this is they wanted the source of their gold to stay secret. Since Sahelian kingdoms/empires like Ghana and Mali controled 2/3's of the worlds gold at one point.
But more important in the TST it was slaves coming IN than the other way around. And when I mean slaves coming in, I mean European slaves. During the times of the Moors there has NEVER been any black slaves linked to the TST being exported out of Africa. We only start to see black slaves linked to TST AFTER the Moorish period and AFTER the fall of those powerful Sahelian empires:
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Africa from the Seventh to Eleventh Century, UNESCO, 1988
It is a myth that wont go away that the Moors sold black slaves in large numbers. And also that large amounts of blacks were linked to the TST. If anything the Moors enslaved/imported large numbers of European female slaves which had an impacted on modern day Berbers(Moors) DNA; their Mtdna being a result of European slave woman and their Y-DNA being African E-M81(African slave master). Thats what most Northwest Africans in general are a result of in ancestry.