Gardaí are teaming up with the PSNI to target fish poachers.
'Operation Silver Fin' originally got underway in Toome, Co Antrim - located on Lough Neagh - several months ago.
The operation's now being moved to Strabane, which is located on the River Foyle and near the North's border with Donegal.
Officers will focus on encouraging the public to report poaching to authorities, as well as enforcing fishing regulations.
Officials say poaching can have serious impacts on the "economic, environmental and cultural lives of communities", as well as endangering the conservation status of some fish species.
PSNI Sgt James McLaughlin explained: "PSNI are committed to tackling wildlife crime including fish poaching in conjunction with our partners. Wildlife crime is taken extremely seriously by the Police Service of Northern Ireland.
"The significance of this kind of crime cannot be over stated."
Superintendent Martin Walker of An Garda Síochána added: "I fully endorse the collaborative efforts of all the enforcement agencies associated with this wonderful initiative to robustly challenge the illegal activities associated with all forms of fish poaching."
The operation will also involve the cross-border Loughs Agency and the Partnership for Action Against Wildlife Crime.