PopeJ,
I use the default typ and style, earlier various known wilderness/protected areas, on land, did not render at all. After trial and error, a lot, using different typ and style I found the problem. One of the results was the marine areas such as you pointed out were "nature reserve" color. I did play around with draw order and resolution but found, for now, the least worst solution is to keep, as is. I found that almost all those marine areas, on any of my maps are just sea/ocean. In the case of those island areas near Los Angeles there may be some oil platforms, but I have # all of those sorts of point, lines and poly's in the style sheets, so they won't show up anyway. As I pointed out in my first post, OSM is Euro centered so I've adapted the best I can for US and North America in general given I'm still learning the fine art of osm/mkgmap mapmaking.