This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鱞 combines 魚 (fish) with 睘, which likely contributes a phonetic element. The exact historical development is uncertain.
With 魚 on the left, this kanji likely relates to fish, but its specific meaning is unclear. Picture a rare, mysterious fish with a complex body shape like the right side 睘.
For カン, imagine a can of rare fish: can -> カン, and the fish part 魚 reminds you it's about fish.