The detained fishermen are from Rajbari, Pabna and Manikganj districts.
Shibaloy upazila Senior Fisheries Officer Rafiqul Islam said: “Upazila Nirbahi Officer Shamsul Alam led a drive at different points and detained 43 fishermen on Monday morning.”
On the other hand police nabbed 14 fishermen in Daultapur, confirmed local OC Rakibuzzaman.
Legal action would be taken against them in mobile court, the OC added.
The government has imposed a ban on catching, selling, transportation and hoarding of ilish from October 12 to November 2, the peak of the fish's breeding season.