Trout of the Mesa river Food and drink · Jaraba, Comunidad de Calatayud, Zaragoza Image of Jaraba, not of the place itself. The river Mesa, a tributary of the Piedra belonging to the Ebro basin, flows through the provinces of Guadalajara and Zaragoza and empties into the Tranquera reservoir, in Nuévalos; at Jaraba it receives a large amount of water from its thermal springs. Its cold waters, especially as it passes through the gorges, sustain a population of trout, and in the past it was also home to abundant Iberian river crayfish, now practically extinct after the introduction of the American red crayfish; there are signs that otters also live there. In the villages along the Mesa and Piedra rivers, trout is prepared floured and fried, a traditional recipe of the area's freshwater cuisine, and a fish farm once operated alongside the river. Photo: Alberto-g-rovi (CC BY-SA 3.0) What to see and do in Jaraba