two possibilities
Dave:I can think of two possibilities for the black specks on your deck.1. They could be spider droppings. If that's what they are then a little (a drop or two) of chlorine bleach on each spot will get them out.2. Gel coat or paint sloughing off. My fiberglass guy told me that when the boat is made small bubbles are under the surface and after countless foot steps on them the surface finish comes off leaving the fiberglass underlayment in view. That was my problem so he mixed up some gel coat to match my deck color and applied it. I had about a dozen small spots and he charged me $75 to fix the appearance of the deck. He said it is cosmetic only and should never cause a problem to the boat's structure.There may be other causes. Perhaps others will offer up their thoughts.Good luck,Mike