“ The territorial limits of Kentucky extend across the river to low-water mark on the northerly shore. Indiana v. Kentucky, 136 U.S. 479, 519, 10 Sup. Ct. 1051, 34 L. Ed. 329. And we think it clear that no limitation upon the power of that commonwealth to protect fish within her own boundaries by proper legislation resulted from the mere establishment of concurrent jurisdiction by the Virginia Compact. ”