So with the new Mistlands update, there seems to be three lines to follow.
Use the listed bait in the biome to catch the next fish, add the right trophy, move to the next biome, etc.
1-
Bait – Meadows –> Perch (+ Troll Trophy)
Mossy Bait – Forest –> Trollfish (+ Abomination)
Sticky Bait – Swamp –> Hearing (+ Fuling)
Stringy Bait – Plains –> Grouper (+ Lox)
Misty Bait – Mistlands –> Pufferfish
2-
Bait – Meadows –> Tuna (+ Ulv)
Cold Bait – Frost Caves –> Anglerfish (+ Surtling)
Hot Bait – Ashlands –> Magmafish (+ Drake)
Frosty Bait – North –> Salmon
3-
Bait – Meadows –> Pike (+ Serpent)
Heavy Bait – Ocean –> Coral Cod
Source: https://www.reddit.com/r/valheim/comments/zfghk0/new_fishing_progression_lines/