This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鰀 combines 魚 (fish) with 爰, which likely contributes the sound カン. The exact historical development is uncertain.
The left side 魚 suggests a fish, and the right side 爰 is a phonetic component. Without a clear meaning, picture a rare fish whose name is uncertain.
For カン, imagine a can of rare fish: can -> カン, and the fish component 魚 reminds you it's a fish-related kanji.