Some Ocean Populations Declined by Nearly 50 Percent Between 1970 and 2012

Beneath the waves, the ocean teems with vibrant life. Or at least it once did. Mary Beth Griggs for Popular Science reports that a new report suggests that the population of some ocean-dwelling creatures around the world declined by nearly 50 percent between 1970 and 2012. 

The statistic comes the World Wildlife Fund’s Living Blue Planet Report 2015, which looked at the health of the world’s oceans and the impacts of human activity on marine ecosystems. The report tracked 5,829 populations and 1,234 species of mammals, fish and other plants and animals — and it paints a dreary picture of life under the sea. 

The report’s most dire finding relates to population numbers: It finds a 49 percent decline in ocean populations across the board during the 42-year period between 1970 and 2012. There isn't great data on the state of every ocean resident though, so to try and get a sense for a general trend, the report used sharks, marine turtles and sea cucumbers as bellwethers for marine health.

The WWF found that one in four species of sharks and rays could soon go extinct due to overfishing — a trend that could spark a chain reaction that trickles down to other animals. Despite increased conservation efforts, four out of seven marine turtle populations are “critically endangered,” and Eastern Pacific turtle populations are down 97 percent in the past three generations. And global demand for sea cucumbers has ravaged ocean populations — fishing has cut Galapagos sea cucumbers by 98 percent since just 1993. Things aren't any better for tuna and mackerel: The report shows a 74 percent decline in the species. 

“These findings coincide with the growing decline of marine habitats,” notes the WWF in a release. “Coral reefs could be lost across the globe by 2050; and almost one-third of all seagrasses have been lost.” Griggs writes that increasing marine protections could stave off the crisis, creating more established wildlife areas “with strict enforcement of fishing and development bans.” And organizations like the United Nations are getting more involved in ocean conservation, too. 

But are protected areas enough to stave off further population decline in the world’s oceans? Louise Heaps is the WWF’s chief UK advisor on marine policy and a co-author of the study. She tells The Guardian’s Fiona Harvey that overfishing is just the tip of the iceberg: Pollution, climate change and acidification are also to blame. But even Heaps is urging ocean lovers not to panic. “It’s not all doom-and-gloom,” she tells Harvey. “There are choices we can make. But it is urgent.” 

Erin Blakemore | | READ MORE

Erin Blakemore is a Boulder, Colorado-based journalist. Her work has appeared in publications like The Washington Post, TIME, mental_floss, Popular Science and JSTOR Daily. Learn more at erinblakemore.com.