basin
(1) Whenever two or more States having a common interest in any basin jointly enter into a cooperative agreement with the Secretary under subsection (a) of this section to carry out a research and development program to conserve, develop, and enhance anadromous fishery resources of the Nation, or fish in the Great Lakes and Lake Champlain that ascend streams to spawn, the Federal share of the program costs shall be increased to a maximum of 66⅔ per centum. For the purpose of this subsection, the term “basin” includes rivers and their tributaries, lakes, and other bodies of water or portions thereof.