October is National Seafood Month, but a new study published by the World Wildlife Fund suggests you probably shouldn't celebrate with a seafood tower. The WWF's Living Blue Planet Report found that populations of marine vertebrates—fish, mammals, birds, and reptiles—fell by 49 percent between 1970 and 2012. Some of the fish we love to eat have been hit even harder, with fish in the tuna, bonito, and mackerel families declined by 74 percent between 1970 and 2010. That includes blue and yellow-fin tuna, some of the top dogs in sushi.
The Living Blue Planet Report isn't the first study to say that the oceans and its inhabitants are in poor shape. One study famously said that the oceans could be fish-free by 2050 at the rate we're going before a later study walked back the claim. Such dire predictions have led to calls for sustainable seafood, and guides like the Monterey Bay Aquarium's Seafood Watch, the National Oceanic and Atmospheric Administration's FishWatch, and Greenpeace's grocer guide aim to help consumers choose fish that are caught using more ocean-friendly methods and aren't critically endangered.
The report points to a number of factors playing into the decline in fish and the deteriorating environment of the oceans. There's climate change, which can warm the oceans and lead to acidification that can kill off important habitats like coral reefs, which one study projected could disappear by 2050 at current rates. There's coastal degradation and pollution, too. Eight million tons of plastic waste is dumped in the ocean each year, set to double by 2025 according to one study, which is troublesome for those hoping to curb the growth of the Great Pacific Garbage Patch. One study found that a quarter of all fish sold contains man-made trash.
But the biggest issue for fish populations is overfishing, with 29 percent of fisheries overfished and 61 percent fully exploited, the report says. Illegal fishing is a big concern, too, particularly in developing countries of the Southern Ocean, accounting for somewhere between 12-28 percent of the global fish catch and an estimated $23 billion annually. Fishing techniques like longlines and trawling that result in bycatch—fish or other species caught unintentionally—are particularly problematic, and the report cites a 2005 study that estimated there are 7.3 million tons of bycatch annually. The WWF says that includes 300,000 small whales, dolphins, and porpoises that die tangled in fishing nets.
There are less obvious casualties, too. The study found that a third of its sea grasses have been lost, and deforestation of mangroves is proceeding at three to five times the average rate of deforestation on land. These are important habitats and spawning grounds, not to mention coastal buffers.
And consider the sea cucumber, a luxury item in Asia, which has been heavily harvested since the early 1980s. The report highlights the case of the Galapagos, where the first legal sea cucumber fishery opened in 1993 and where by 2004 the population of sea cucumbers had declined 98 percent.
It's undeniable that we're eating more fish these days, twice the amount per capita compared to fish consumption in the 1960s. And with the world population set to grow to more than 9 billion this century, fish will continue to be an important source of protein for people the world over, not to mention the center of an industry employing millions.
It's not all doom and gloom, though, and the WWF points to better fishing techniques that eliminate bycatch, reduction in carbon emissions and better regulation of fisheries as ways to turn the tide. Other efforts include feeding farmed fish vegetarian fish feed and calls to eat fish at the bottom of the food chain to give bigger fish populations a chance to rebound. Here in the United States, NOAA reported that overfishing and the number of overfished stocks hit an all time low last year. Just one more reason to buy local.