There are at least three main sections, of this, not including the area around Andris, which from NW to S. is essentially one long Gaper coast.
Gapers, like Pixies, do enjoy their vacations by the waters of Oberin, much like Sea Serpents like to spend time by the shore. Even Bracken like to dip their roots far out to the ocean, proper.
Such is the environment of the North end of Oberin for 4.5 patches, stretching from Duldrus, possibly a Gaper nesting site, to about 3 /5's of the way from W. to E., to Marali.
Another further 1.5 patches stretch between Duldrus and Mirith, while from Welif to the Andris Bridge, there are about 2.
To the SE end of the main Continent, Gapers in small patches exist first above the Andris Bridge, then continue through the entire Lerilin Bridge area, further NE in 2 or so more patches up until Aborek.
Gapers finally exist along the NE Marali coast, in one further patch.
That works out to about 5-6 sections (if Andris is one), and 10-12 patches (ditto).