Only the green marks are visible ABS denuded of the outer vinyl layer and they are quite modest.
No harm done if you want to cover those streaks with some spray paint (Krylon Fusion or other) but I certainly wouldn't do any more.
Of course, those old whitewater Royalex canoes will wear into the foam core of the ABS eventually and it usually happens in the area under the pedestal which draws a significantly deeper draft in a highly-rockered boat and where the paddler's weight is concentrated. Sometimes it is hard to judge when the outer ABS stratum is getting thin to the point of breaking through but it usually only happens after a sizable patch of ABS is denuded. Sometimes you can tell by pushing hard with your thumb and seeing if the ABS indents a bit.
My old Encore (a fuscia one by the way) did wear through and I repaired it with a three layer patch of E 'glass under the pedestal area using G Flex and it seems to have held up just fine so far.
Touring Kayak Paddles
Reflective Hull Decals
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