Costa Rican officials, northern zone residents and tarpon fishermen everywhere are casting a concerned eye on Nicaragua.

That’s because Nicaraguan President Enrique Bolaños formally presented his nation’s plans for an inter ocean canal to visiting defense ministers in Managua Monday.

The presentation comes just a short time before residents of Panamá can vote on widening the canal in their country.

But for Costa Rica, the Río San Juan is the concern. The plan is to use the existing river, widen it and use it to connect the Caribbean with Lake Nicaragua.

The Rio San Juan is world class tarpon waters, and fishing is high on the tourism priorities list. Those involved in that activity are concerned that heavy dredging on the river channel that is in Nicaragua could hurt the flow in the river channels of the Río Colorado that enter the Caribbean from Costa Rica. The flow also feeds the Tortuguero area and Parque Nacional Barra del Colorado.

Tarpon notwithstanding, the Río San Juan has been a political flash point for Costa Rica, and both nations are now in the International Court in the Hague where Costa Rica is pressing for access and travel rights on the river. The river is not the border between the two countries but is entirely in Nicaragua.

Residents and workers in the underdeveloped northern zone use the river as a highway. Depending on the political wind, travel may be easy or made more difficult by Nicaraguan officialdom.

Costa Rican officials are unlikely to calmly accept a gigantic and possibly environmentally damaging public works project just feet from the border.

The Nicaraguan canal project is pegged at about $18 billion. And the idea has been considered for 150 years.