The study, conducted by a group of internationally known marine scientists and economists, reveals that a variety of factors including overfishing, destruction of marine habitat, pollution and alterations in the ocean's biogeochemistry caused by climate change are taking a dramatic toll on life in the sea. Unless steps are taken to address these problems, there will be virtually no more wild seafood available on a commercial basis beyond the middle of this century.
The authors of this landmark study concluded that stresses to the world's oceans are dramatically reducing the ability of many marine organisms to survive, and that we are losing them at a faster rate than previously estimated. With the growing loss of species in the world's oceans, the entire marine system is beginning to unravel. This has enormous potential consequences to Earth's human population, which depends on ocean resources for jobs and income, food, medicines and a variety of ecosystem services such as filtering pollutants and absorbing carbon dioxide from the atmosphere that play a critical role in maintaining and ensuring quality of life on Earth.
The potential impact of a collapse (defined as 90 percent depletion) of the world's commercial fisheries are staggering. Fishing produces about $80 billion in revenue each year. Over 200 million people worldwide depend directly or indirectly on fishing as their principal livelihood. And more than 1 billion people, many of whom are among the poorest on Earth, rely on fish as their main source of animal protein.
A collapse of commercial fisheries on a global scale, with an accompanying decline in ecosystem services provided by a diverse and healthy marine environment, would have massive repercussions on the economies of coastal communities and states, and on the quality of human life worldwide. Revenue from ocean-related tourism, in the tens of billions, would decline, as would the value of ocean property in many areas experiencing ecological failure.
Moreover, the negative impacts of accelerating species loss in the sea transcend those that are simply economic. Entire communities would lose their way of life, with profound social consequences resulting from job loss, human dislocation, and deteriorating social services caused by a declining base of revenue. Likewise, the impacts on human health are likely to be significant, including greater prevalence of disease and infections caused by increasing coastal pollution, the invasion of exotic species, and declining human nutrition caused by accelerating protein deficiency.
The good news is there is still time to prevent most of these things from happening. There is great resiliency in the sea. Many populations of fish and other marine species will come back, if we simply give them a chance to recover. Halting the destruction of coastal habitat and taking steps to control and reduce pollution would help to restore the productivity of many areas of the world's oceans.
Most important, however, is putting an end to overfishing. Each year, it is estimated that humans remove about 150 million tons of life from the sea. The global marine environment cannot withstand these losses. The world's coastal nations must take steps to sustainably manage those fisheries within their own territorial waters and to restrict the use of destructive fishing gear that damages marine habitat and results in the incidental killing of huge numbers of fish and other marine species such as seabirds, turtles and dolphins that are thrown overboard dead and dying because they are unwanted.
Finally, a massive effort must be mounted to reign in illegal and unsustainable fishing on the high seas, that area of the world's oceans that lies beyond the 200-mile limit from shore, and is exploited by all countries, but protected by none.
For most of human history, the sea has provided a healthy bounty of food and other essential services to people. It can continue to do so, but not unless we reduce the number of fish we catch, and change the way we catch them. The time has clearly come to act, both nationally and globally. If we fail, the next generation will be facing far greater problems than simply having no fish to eat.