The word "鲈鱼" is formed by combining the character "鲈", which specifically denotes perch, with the character "鱼", meaning fish. The character "鲈" itself is constructed using the semantic radical "鱼" on the left to indicate its relation to fish, and the phonetic component "卢" on the right to suggest its pronunciation "lú". Thus, "鲈鱼" directly signifies "perch fish" through this compositional structure.