This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鰚 is a rare character combining 魚 (fish) with 宣. The exact historical development is uncertain, and it may be a kokuji or a specialized variant.
The left side is a fish 魚, and the right side is 宣, which can suggest proclamation or spread. Without a clear meaning, picture a rare fish that was once proclaimed in ancient texts but is now obscure.
For はらか, imagine a fish (魚) being proclaimed (宣) as 'haraka'—a made-up name for a legendary fish. The sound 'haraka' echoes through the market as the fish is announced.