This video says about itself:
15 April 2015
However, ever since the 1970s, their numbers declined.
Recently, some fishermen say the numbers are going up again.
To see whether that is true, some shrimp fishermen will tag sharks which they catch, and release them.
Today, 28 August 2015, was supposed to be the start of this. However, the young school shark caught today was too small to tag, so it was freed without having been tagged.