When I first read Moby Dick, I was struck by Melville's insistence that there was no way that the whaling industry could threaten the overall existence of whales. The ocean was so vast, and the hunting methods were so inefficient, that the whales would always exist in huge numbers. Even though he goes into great detail (and praise) for the factory ship systems of that day, he simply did not see any way humans could threaten the existence of so plentiful a species.
My father went to high school in the late 1930s, and he told me about the humiliating day his teacher ridiculed him in front of the class for writing an essay in which he dared suggest that human actions could threaten the continued existence of certain animals. Did he realize, the teacher asked him in wonder, how vast were those numbers and how puny were man's ability to diminish them?
That was not that long ago. My father graduated from high school only a few years before Cousteau first went under water with his aqualung and camera. We have since developed the ability to destroy ecosystems far beyond what we could have imagined only recently. When Cousteau first started diving, sharks were everywhere in abundance; it is only in the last few decades that we were able to kill 90% of them and see what a devastating effect that slaughter has created. It is only in the past few decades that fishing methods have become so effective that we are now able to strip the word's oceans of fish with little more effort than we are using now.
Unfortunately, the idea of an eternal abundance in the seas still lingers in the minds of many. Jacques may well have been infected with it still when he began his career, but his descendants have a completely different attitude now.