Hopes that Greece’s long-defunct caviar industry could make a comeback were revived yesterday after fishermen discovered a rare type of sturgeon in the delta of the River Evros in northeastern Greece after an absence of 30 years. The five-month-old fish, which measured 35 centimeters, was located in the river on Tuesday and was taken to nearby Alexandroupolis for tests. It was due to be released back into the water yesterday at the same spot it was found. European sturgeons and other species of the fish have been listed as endangered by international authorities. Sturgeons were last seen in Greek waters in 1975. It was also the last time that Greece produced its own caviar, which is made from the eggs of sturgeons. Experts said that this species returns to spawn in the same waters in which it was born, prompting hopes that more sturgeons may soon be found in the area.