The 22-day ban on catching and selling hilsa began from Tuesday midnight and will continue till November 4.
The government imposed the ban in a bid to protect mother fish during peak breeding season.
River police, Bangladesh Coast Guard and the Department of Fisheries will jointly implement the hilsa protection campaign at 152 upazilas of 36 districts of the country.
The government will provide adequate food assistance to fisherfolk who cannot collect or sell hilsa during the ban so that no one involved in this process faces food crisis.