Global wildlife populations will decline by 67% by 2020 unless urgent action is taken to reduce human impact on species and ecosystems, warns the biennial Living Planet Index report from WWF (World Wide Fund for Nature) and ZSL (Zoological Society of London). From elephants to eels, here are some of the wildlife populations most affected by human activity. Here: The maned wolf is among the large mammals in the Brazilian Cerrado that are threatened by the increasing conversion of grasslands into farmland for grazing and growing crops. (Photo by Ben Cranke/Nature Picture Library/Alamy Stock Photo)

Well before Corey Arnold ever thought about photography, he fished. As a child, he dressed as a fisherman for four consecutive Halloweens, and once brought a dead 3-foot Mako shark to school for show-and-tell. He knew he wanted to be a professional fisherman, even if he didn’t understand what that actually meant.

A small section of the expanding remains of the Veil Nebula, a massive star that exploded about 8,000 years ago. The entire nebula is 110 light-years across, covering six full moons on the sky as seen from Earth, and resides about 2,100 light-years away in the constellation Cygnus, the Swan. Image taken by NASA's Hubble Space Telescope. Released September 24, 2015. (Photo by Reuters/NASA/ESA/Hubble Heritage Team)

A Mongolian Bloody Mary, made with pickled sheep eyeballs and tomato juice, is displayed at the Disgusting Food Museum in Malmo, Sweden November 1, 2018. (Photo by Mikael Nilsson/Reuters)

Turkish police detained dozens of demonstrators participating in an LGBT pride march in Istanbul, Turkey on June 26, 2021. Police fired tear gas, rubber bullets and blocked attempts by protesters to gather in large numbers after a government decision to ban pride events in recent years. (Photo by Diego Cupolo/NurPhoto/Rex Features/Shutterstock)

A view of a turtle during an event at the Ministry of Environment in Phnom Penh, Cambodia, 24 June 2020. A Cambodian woman recently bought endangered Royal Turtles from local villagers and gave them to Ministry of Environment. (Photo by Kith Serey/EPA/EFE)

A man shows golf ball-size hail outside Parliament House after a severe hail storm hit Canberra, Australia, 20 January 2020. (Photo by Mick Tsikas/EPA/EFE)

Milena Jami whips her llama to win the first place in the a race for children of ages seven and eight at the Llanganates National Park, Ecuador, Saturday, February 8, 2020. Wooly llamas, an animal emblematic of the Andean mountains in South America, become the star for a day each year when Ecuadoreans dress up their prized animals for children to ride them in 500-meter races. (Photo by Dolores Ochoa/AP Photo)