Reading wind barbs from here:
Each short barb represents 5 knots, each long barb 10 knots. A long barb and a short barb is 15 knots, simply by adding the value of each barb together (10 knots + 5 knots = 15 knots). If only a station circle is plotted, the winds are calm.
With the lighter winds offshore Somalia to the east, more pirate attacks would be expected in that area over the next few days, though it depends on the number of pirate operatives in that area.
UPDATE: Another wind barb explanation from here: