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Marine species have declined by almost half over the last forty-five years, according to the World Wildlife Fund's Living Planet Index, and leading marine scientists tell VICE News that the only hope of stopping mass death in the oceans is to radically and quickly transform human behavior.

Based on a study of 5,829 populations of 1,234 mammal, bird, reptile, and fish species in the world's oceans, the WWF found a decline of 49 percent between 1970 and 2012. Fish were the most threatened, in large part because of human overfishing: Over a third of fish consumed by humans measured by the Living Planet Index are under threat of extinction, with one family of tuna and mackerel falling 74 percent between 1970 and 2010.

Other animals that recorded massive and ongoing losses were sharks and rays, of which one in four species is threatened with extinction, and some species of turtles, which declined by 97 percent in the Eastern Pacific.

The mass death of larger animals is tied to the decimation of habitats that are critical to the ocean's biosphere. The WWF also noted that coral reefs — which support 25 percent of all marine life — could go extinct by 2050, and global surface areas of seagrass and mangroves, which provide spawning grounds, nutrients, and shelter for many animals, have declined precipitously.

The foundation attributes the death to a network of interrelated human behaviors, including overfishing, aquafarming, island- and ocean-based tourism, pollution, climate change, and offshore drilling in the oceans, which accounts for around a third of all oil and gas extracted worldwide. All of these factors have accelerated since the 1970's because of a rising standard of living globally, according to Michele Kuruc, the WWF's vice president of ocean policy.

"I've been doing this for 30 years, and I've seen some of the worst things in my lifetime," Kuruc said, "but I've also seen an optimistic trajectory starting to form with more awareness around a lot of this and understanding the need for us to change how we engage with the oceans."

Kuruc maintained that despite unprecedented levels of carnage in the oceans, she is buoyed by President Obama's announcement last fall of a special task force to fight illegal, unreported, and unregulated fishing. The WWF report cited overfishing as a leading cause of fish population decline, with 29 percent of the world's fish stocks classified as overfished and 61 percent as "fully exploited," meaning they have no ability to produce greater harvests.

One of the presidential task force's first efforts will focus on implementing a system to trace the origins of fish imported to the United States, which represents 90 percent of seafood consumed by Americans. More broadly, the task force will also enhance coordination between the federal government and local agencies and encourage America's trading partners, including China, to crack down on unregulated fishing. The European Union, which represents 40 percent of the global fishing market, announced a similar initiative five years ago.

Phil Dustan, a marine biologist at South Carolina's College of Charleston and the principal investigator of the Environmental Protection Agency's Coral Reef Monitoring Project, emphasized that while the decline in marine life is attributable to a number of factors, cracking down overfishing would give ocean habitats a chance to recover from the damage humans have caused.

"If you stop taking the pieces out of these ocean civilizations, they can begin to rebuild themselves," he told VICE News. "It's never going to regrow itself the way it was 50 years ago, and we are going to have to do the best we can and limp along in the Anthropocene, but we have to do what we can to stop the carnage and allow these systems the space to regrow."

A growing contingent within the scientific community argues that because of human influence on the air, water, and soil we are no longer living in the Holocene epoch, which began about 11,700 years ago with the end of the Ice Age, but are now in the Anthropocene — The Age of Humans.

Dustan added that the root of ocean destruction was human overpopulation, and he emphasized that education and reproductive rights were similarly critical to reversing ocean destruction. A focus on broader human behavior was echoed by Douglas J. McCauley, an ecologist at the University of California, Santa Barbara who recently authored a major study on the human-caused destruction of ocean fauna.

"It's great we are combatting overfishing, but if we are serious about biodiversity, I say in two months we are going to have a chance to do something serious for the oceans in Paris," McCauley said, referring to the UN's annual climate change conference later this year, where world leaders will attempt to agree on a pact aimed at avoiding dangerous levels of global warming. .

"I would say that those two weeks of negotiations are going to decide a thousand years of future in the oceans," he told VICE News.

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