Jacques Cousteau is known for being a “late-bloomer” conservationist, as he spent the initial parts of his life engaging in behaviour that was the complete opposite of conservation (such as capturing marine life in the name of science/research which resulted in their death).
However, as he began to explore the oceans even further, his eyes opened to the amount of damage that humans are doing to marine life and oceans. Hence, he began to devote effort to marine conservation and raising awareness for it.
This shows that human morals and ethics is not set in stone, and in fact, can even experience a 180-degree change. This is in line with the Pragmatism School of Ethic, which states that people can continuously reevaluate and improve their moral code through learning. As Cousteau learns more about the marine life, his morals began to change too, eventually changing his behaviour as well. Cousteau attempts to replicate what he went through for the public through his films and books, which we will find out more about later on.