This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鮍 combines 魚 (fish) with 皮 (skin/hide), likely a phono-semantic compound where 皮 contributes the sound and the meaning relates to a type of fish, possibly a filefish or triggerfish with rough skin. The exact historical development is uncertain.
The left side is a fish 魚, and the right side is skin 皮. Picture a fish with tough, leathery skin that needs to be peeled or scraped.
For ヒ, imagine the fish's skin being so tough it makes a hissing sound when you try to cut it: hiss -> ヒ.