Sharks are displayed after being unloaded from wooden boats in a fish port in Banyuwangi in Indonesia's East Java province in 2008. Three shark attacks in Australia in two days that year sparked a global media frenzy of "Jaws" proportions, but sharks are more at risk in the ocean than humans with man killing 100 million sharks each year. Reuters

New analysis of our oceans projects a dire future for Earth’s shark and ray populations. A study more than 20 years in the making found that one-quarter of all shark and ray species face extinction within the next few decades.

A team of nearly 300 scientists conducted what is the first systematic analysis of the conservation status of sharks, rays and chimaeras (known informally as “ghost sharks” or “ratfish”). Researchers from the International Union for the Conservation of Nature, the world’s largest and oldest global environmental network that keeps a “Red List” of threatened species, looked at the number of sharks left in our oceans as well as the causes of their population collapses. They found that overfishing, the global market for shark fin soup and killing of large predator sharks because of human fear have all caused shark and ray populations to plummet over the years.

“Our analysis shows that sharks and their relatives are facing an alarmingly elevated risk of extinction,” Nick Dulvy, a researcher at Simon Fraser University in British Columbia, Canada, and co-chair of the IUCN’s Shark Specialist Group, said in a statement. “In greatest peril are the largest species of rays and sharks, especially those living in shallow water that is accessible to fisheries.”

The study, published in the journal eLife, looked at the population statuses of 1,041 chondrichthyans – the class of jawed fish that includes sharks, rays and chimaeras. Researchers concluded that 181 of the 1,041 species observed are threatened; 25 species are considered critically endangered; 43 species are endangered; 113 are considered vulnerable and 132 species are deemed “near threatened.” Only 23 percent of them were considered “least concern.”

"Surprisingly, we have found that the rays, including sawfish, guitarfish, stingrays and wedgefish, are generally worse off than the sharks, with five out of the seven most-threatened families made up of rays," Colin Simpfendorfer, co-chair of the IUCN Shark Specialist Group and professor of environmental science at James Cook University in Queensland, Australia, said in a statement. "While public, media and government attention to the plight of sharks is growing, the widespread depletion of rays is largely unnoticed. Conservation action for rays is lagging far behind, which only heightens our concern for this species group."

The most threatened families of sharks and rays, according to the report, are sawfishes, angel sharks, wedgefishes, sleeper rays and whiptail stingrays. Many of these are killed in the form of bycatch, getting caught in commercial fishing nets.

While the global shark fin trade is also a major concern, the authors highlight other, lesser-known threats to shark populations. They include the trade in shark and ray meat, manta ray gill rakers and liver oil.

Additionally, sharks are threatened because of their killer reputation. Sharks often get a bad rap because of sensational stories that appear in the media about shark attacks, even though worldwide, annual shark attacks number less than 100. In comparison, mosquitoes are responsible for more than 600,000 deaths a year, primarily in Africa, where the insect spreads malaria. Hippos kill roughly 2,900 people every year; even deer kill more people in the U.S. annually than sharks do globally.

“Sharks have a PR problem that might be hurting their chances of survival,” Live Science noted in a 2013 article on sharks’ decline. “A study out last year found that a majority of the media coverage they get involves shark attacks on humans, which doesn't reflect how rare these scary encounters are.”