Why we need the oceans - and why they need us: the voyage "Around the Americas" hopes to draw attention to the revitalization of the world's waterways.

• Author: Rockefeller, David, Jr.
• Position: Worldview

THE CLIMATE skeptics were out early this year, fresh from shoveling snow where it rarely falls. Their theme is that environmental problems are not caused by human actions, but mostly are the result of natural cycles. Whatever your personal view of global warming, we need to be concerned about our oceans because, for centuries, we humans have been putting in what does not belong there and taking out entirely too much.

Ten years ago, I sat on the Pew Oceans Commission and learned in detail about how we systematically have been spoiling our oceans by using them mindlessly as a depository for our everyday waste, while, at the same time, extracting things vital to the seas' longterm health and viability. Nothing less is at stake than our health and food supply--and the culprit is not an abstraction; it is us.

Since World War II, the confluence of rapid population growth worldwide (demand) and technologically sophisticated fishing vessels (supply) effectively removed 90% of the large fish from the ocean. Yet, we persist in taking an unsustainable share of what remains. By 2025, worldwide seafood demand is projected to increase by more than 60% and, if left unchecked, the current stock of all species currently fished could collapse by mid century. The result is that the 1,000,000,000 people who depend upon seafood as their principal source of protein--as well as anyone who loves to eat from the sea--are at risk of losing that part of their diet entirely.

Global consumption of bluefin tuna has sky-rocketed since 1970. The Obama Administration recognizes the seriousness of putting ocean species at risk and has endorsed a full ban on the international Wade of Atlantic bluefin tuna, the strictest protection yet for these endangered giants. However, the Convention on International Trade in Endangered Species (CITES) rejected the ban, drawing sighs of relief from sushi chefs and fishermen everywhere.

One promising solution to the decline in wild stocks has been the rise of aquaculture and fish farming. Some 50% of the seafood now consumed worldwide is farm raised, but this fast-growing industry also has spawned some problems of its own. For instance, in salmon farming--a practice that usually involves "feeding pens" anchored to the ocean bottom in near-shore colonies--overcrowding in the pens can lead to disease, which then tempts farmers to use antibiotics that pass into human consumers. In addition, the salmon that escape and reproduce alter the...