There is a slight issue with this concept.
Sharks don’t have scales, they have a skin.
Their skin is very rough, and in fact it could be used as sandpaper.
The problem with dimples on surfboards in the past is that they have all been around the 2 to 3 inch size. The “dimples” on a shark are less than a millimeter (fractions of an inch).........
....And in fact are tiny little raised dots, not unlike a non-skid surface on a boat. (With me RM?).
Don’t know if that would work on a ridged structure like a surf board.
If you really want to find out paint the bottom of your board with a marine non-skid paint.
As for me I'm happy with a wet rub.
Wet rub
No thats not a crude Australian joke, a wet rub as in sanding the bottom.
No, No the bottom of the surfboard

Imagination is more important than knowledge.
For knowledge is limited to all we now know and understand.
While imagination embraces the entire world, and all there ever will be to know and understand.
Albert Einstein ... Yeah Bert.