Thirteen fishing boats, including eight mechanised ones, were seized by Mandapam Marine police personnel near Katchatheevu today for allegedly using banned nets. The boats were seized during a patrol by a team of Fisheries Department officials led by Assistant Director D Kulanchinathan. Apart from the eight boats, the nets were also seized, Kulanchinathan said. Police said the owners of these boats would be prosecuted and penalised by court. Also, five country boats were detained near Pamban on similar charge of using banned nets.