The encyclical letter Laudato Si is available here on the Vatican website.
40. Oceans not only contain the bulk of our planet’s water supply, but also most of the immense variety of living creatures, many of them still unknown to us and threatened for various reasons. What is more, marine life in rivers, lakes, seas and oceans, which feeds a great part of the world’s population, is affected by uncontrolled fishing, leading to a drastic depletion of certain species. Selective forms of fishing which discard much of what they collect continue unabated. Particularly threatened are marine organisms which we tend to overlook, like some forms of plankton; they represent a significant element in the ocean food chain, and species used for our food ultimately depend on them.
Jacques Cousteau comes to mind as a popularizer of ocean exploration in the last century. Thoughtless exploitation of ocean resources not only damage undersea environments, but they also impact human life and culture, as food sources and means of work are altered or disappear.
Catholic Sensibility 