El Castillo has some tasty places to eat while options are more limited in Boca de Sábalos and fairly poor in San Juan de Nicaragua. All riverside lodges serve meals for their guests, however, so you won't go hungry.
Tourism and the Disappearing River Shrimp
When travelers began flowing into the Río San Juan, they quickly developed a taste for one of the region's delicacies: the giant river shrimp, which had long been enjoyed grilled or sautéed in garlic by local residents.
However, instead of local families enjoying the crustacean now and again, with the influx of visitors it was suddenly on menus all along the river all the time.
Unfortunately, harvesting wasn't regulated and large quantities of shrimps of all sizes were being hauled out of the river and served to hungry travelers. Needless to say this was a disaster for local shrimp populations and now the tasty critter is nowhere to be found in the area around El Castillo where they were once abundant.
Some shrimp are still being caught way downriver near San Juan de Norte but in far smaller quantities than before and there is little evidence that these are being harvested more sustainably. To compound the problem, local efforts to breed the animal in captivity have proven unsuccessful.
The dish has disappeared from most local menus where it once was the prize offering, although shrimp imported from far downriver are still being offered in some places. Give it a miss and go for something more sustainable.