Aquaman's first origin story was presented in flashback from his debut in More Fun Comics #73 (November 1941), narrated by the character himself:  The story must start with my father, a famous undersea explorer--if I spoke his name, you would recognize it. My mother died when I was a baby, and he turned to his work of solving the ocean's secrets. His greatest discovery was an ancient city, in the depths where no other diver had ever penetrated. My father believed it was the lost kingdom of Atlantis. He made himself a water-tight home in one of the palaces and lived there, studying the records and devices of the race's marvelous wisdom. From the books and records, he learned ways of teaching me to live under the ocean, drawing oxygen from the water and using all the power of the sea to make me wonderfully strong and swift. By training and a hundred scientific secrets, I became what you see--a human being who lives and thrives under the water.  In his early Golden Age appearances, Aquaman can breathe underwater and control fish and other underwater life for up to a minute. Initially, he was depicted as speaking to sea creatures "in their own language" rather than telepathically, and only when they were close enough to hear him (within a 20 yards (18 m) radius). Aquaman's adventures took place all across the world, and his base was "a wrecked fishing boat kept underwater," in which he lived.  During his wartime adventures, most of Aquaman's foes were Nazi U-boat commanders and various Axis villains where he once worked with the All-Star Squadron. The rest of his adventures in the 1940s and 1950s had him dealing with various sea-based criminals, including modern-day pirates such as his longtime archenemy Black Jack, as well as various threats to aquatic life, shipping lanes, and sailors.  Aquaman's last appearance in More Fun Comics was in issue #107, before being moved along with Superboy and Green Arrow to Adventure Comics, starting with issue #103 in 1946.

Answer this question "What were his powers in the Golden Age?" by extracting the answer from the text above.
Aquaman can breathe underwater and control fish and other underwater life for up to a minute.