West Bromwich Albion's Saido Berahino (front) is challenged by Manchester City's Fernandinho during their English Premier League soccer match at The Hawthorns in West Bromwich, central England December 4, 2013. (Photo by Eddie Keogh/Reuters)

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.

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)

Singer Rihanna prepares for a photoshoot with photographer Annie Leibovitz in Havana, Cuba, May 28, 2015. (Photo by Reuters/Stringer)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

An Indian man, Kalpesh Modi, performs stunts with his motorcycle during the rehearsal for the forthcoming Lord Jagannath Rath Yatra, an annual Hindi festival, in Ahmedabad on June 23, 2019. The 142nd Lord Jagannath Rath Yatra festival in Ahmedabad is scheduled for July 4. (Photo by Sam Panthaky/AFP Photo)

Lukas Podolski of Koeln is challenged by Philipp Wollscheid of Nuernberg during the Bundesliga match between 1. FC Koeln and 1. FC Nuernberg at RheinEnergieStadion on April 3, 2011 in Cologne, Germany.

A visiitor bungee jumps during an outdoor festival to celebrate German Unity Day on the 21st anniversary of German reunification on October 3, 2011 in Berlin, Germany. German Unity Day is a national holiday and marks the day West Germany and East Germany were reunited in 1990 following the collapse of the Iron Curtain. (Photo by Adam Berry/Getty Images)