The boundary between the southeastern and Chugach regions shall be the 141st meridian: Provided, That the Regional Corporation for the Chugach region shall accord to the Natives enrolled to the Village of Yakutat the same rights and privileges to use any lands which may be conveyed to the Regional Corporation in the vicinity of Icy Bay for such purposes as such Natives have traditionally made thereof, including, but not limited to, subsistence hunting, fishing and gathering, as the Regional Corporation accords to its own shareholders, and shall take no unreasonable or arbitrary action relative to such lands for the primary purpose and having the effect, of impairing or curtailing such rights and privileges.