1. He was a pioneer in ocean exploration. He and Emile Gagnan invented the aqualung the first underwater breathing apparatus. He also invented many other tools, gadgets, and techniques to safely explore and film underwater.
2. He was a marine conservation advocate. Cousteau was passionate about protecting the ocean and its inhabitants. He worked tirelessly to educate the public about the importance of ocean conservation. He wrote over 50 books about ocean life and founded the Cousteau Society, a non-profit ocean conservation organization.
3. He was an oceanographer, underwater explorer and film maker. He made over 100 ocean documentaries and TV specials about life in the ocean and inspired many people to become ocean stewards.
Reference: https://en.wikipedia.org/wiki/Jacques_Cousteau