Anti-trawling device

Kind of artificial reef

Anti-trawling devices are a specific kind of artificial reef. Trawling is a controversial fishing practice which has attracted environmental, legal, and political objections. Anti-trawling devices have been invented, manufactured, and deployed to damage trawlers' nets and thus slow them down, force them to stop operating, or force them elsewhere. They are usually large concrete blocks with metal hooks or blades embedded in their tops. Anti-trawling devices are being used by environmental groups, fishermen, and sometimes even by governments.

This keyword could refer to multiple things. Here are some suggestions: