Finding out why, or if, Aniseed attracts fish reveals few answers, because aniseed or anything like it does not occur naturally in salt or freshwater.
It seems that aniseed is used mostly in freshwater fisheries especially in Europe. It's use was exported to New Zealand, and was used enough to warrant it's ban on use being printed on early licences.
In New Zealand Aniseed along with all other bait 'enhancers' are banned in trout fishing water, so check your licence carefully.
For further information check out Google, using 'aniseed AND fishing' as your search phrase, exactly as shown (without the quotes), but including capitalisation.
Ainseed is not the only plant 'bait enhancer'. In some places garlic and lemon juice are used. In some freshwater fisheries, baits are often salted.
Article written by Tony Bishop (Bish)