This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鰢 combines 魚 (fish) and 馬 (horse), but the historical origin and intended meaning are uncertain.
The kanji visually contains 魚 (fish) and 馬 (horse), but no clear meaning emerges from these components alone.
For バ, imagine a horse (馬) neighing 'ba' at a fish (魚): ba -> バ.