The ornamental design for a fishingboatpontoon, as shown and described.
FIG. 1 is a perspective view taken from above the right front of the pontoon as part of a fishing boat, with a seat structure and feet rest of the boat shown in phantom for illustrative purposes only and forming no part of the claimed design;
FIG. 2, a perspective view taken from above the right front of the pontoon;
FIG. 3, a top plan view;
FIG. 4, a left side elevation view, the right side elevation view being a mirror image thereof;