1931 CE • Spain
“Sturgeon records from the Guadalquivir are available from the thirteenth century until 1992. From 1931 onwards, the spawning migration was interrupted by the building of the Alcala del Rio dam, causing a decline in all the migratory species. Ironically, a caviar and smoked-flesh factory started to run that same year . . . Additionally, human-induced aggressions such as the building of river dams and the establishment of gravel extraction factories combined with environmental phenomena such as dry springs, which restricted the spawning of sturgeon in the Guadalquivir, also had a negative impact on Iberian sturgeon. In retrospect, one can see that there were no chances of survival for the Guadalquivir sturgeon. The last specimen was caught in 1992 near the mouth of the river.”
Arne Ludwig, Arturo Morales-Muñiz, and Eufrasia Roselló-Izquierdo, “Sturgeon in Iberia from Past to Present,” Biology and Conservation of the European Sturgeon Acipenser Sturio L. 1758 (2011): 131-46.