herring
鰊 centers on a specific fish: the herring. It is a narrow, concrete term without broad abstract extensions.
鰊 combines 魚 (fish) with 柬, which likely contributes the sound レン. The character was created to name the herring specifically.
The left side 魚 means fish, and the right side 柬 looks like a bundle of fish tied together. Picture a bundle of herring caught in a net.
For レン, imagine a herring leaping in a lens-shaped arc: lens -> レン, and the fish jumps like a herring.