A saved but caged Sumatran tiger. A tiny seahorse clinging to a discarded Q-tip cotton swab to swim downstream. Anemone fish showing off parasitic isopods that live inside their mouths (banner, above). An Arctic fox carrying a stolen egg. An elephant matriarch caught in repose after she’s led her herd to water during a dry spell.

These are the finalists in the 53rd annual running of the prestigious Wildlife Photographer of the Year Awards, to be presented Tuesday night at La black-tie ceremony at London’s Natural History Museum.

The awards feature categories ranging from animal portrait to emerging young photographers, aged 11-14. One of the distinguishing features of this year’s competition is that two of the 13 finalists for Wildlife Photograph of the year — the WPOTY equivalent of best-in-show — come from the young age group: Laura Albiac Vilas’ blink-and-you’ll-miss-it glimpse of a rare Iberian lynx in Spain’s Sierra de Andújar Natural Park, and Ashleigh Scully’s serendipitous capture of a bear cub hugging its mother in Alaska’s Lake Clark National Park.

©Ashleigh Scully/2017 Wildlife Photographer of the Year

As in past years, though, it’s the environmental awareness images — the photos that trigger an emotional and intellectual debate about habitat destruction, climate change and the sixth mass extinction — that are causing the biggest stir. Veteran National Geographic big-cat specialist Steve Winter’s image of an adolescent Sumatran tiger snarling in a cage, shortly after having a badly damaged leg amputated, and California photographer Justin Hofman’s image of a seahorse swimming against a sea of muck, are standouts.

©Justin Hofman/2017 Wildlife Photographer of the Year

Hofman’s seahorse, in particular, has gone viral, in part because it’s an artistically striking image — brilliant colour rendition and near-perfect compositional balance — and primarily because it tells such a vital story.

“It’s a photo I wish didn’t exist but now that it does, I want everyone to see it,” Hofman posted on his Instagram account (https://www.instagram.com/justinhofman/). “What started as a cute opportunity to photograph a cute little seahorse turned into one of frustration and sadness as the incoming tide brought with it countless pieces of trash and sewage.”

Hofman captured the image off the Indonesian island of Sumbawa, where he happened to be diving at the time. As striking to the eye as the image is, it tells a disturbing story about the daily travails of marine life living in seas and oceans choked by human and industrial pollution.

“This seahorse drifts along with the trash day in and day out as it rides the currents that flow along the Indonesian archipelago,” Hofman continued on Instagram. “This (image) serves as an allegory for the current and future state of our oceans. What sort of future are we creating? How can your actions shape our planet?”

Indonesia is increasingly in the environmental crosshairs. Winter’s injured tiger was captured in Indonesia; last year’s winning WPOTY image, captured by Tokyo-born National Geographic wildlife photojournalist Tim Laman, was of an Indonesian orangutan — critically endangered, owing to the wholesale destruction of its forest habitat. In a 2015 Environmental Health Perspectives study, Indonesia ranked second only to China among the world’s largest producers of marine pollution on the planet, thanks to more than 3 million metric tons of plastic waste dumped into the ocean every year.

©Tim Laman/2016 Wildlife Photographer of the Year

Hofman hopes his photo will shake people’s complacency and help galvanize change.

This year’s 13 finalists were chosen from a shortlist of 100 images, themselves culled from more than 50,000 entries from 92 countries around the world.

London’s Natural History Museum will present a full exhibition of images from Oct. 20 through the spring, in the hopes that, to paraphrase the late jazz great Louis Armstrong, humanity may once again see skies of blue and clouds of white, the bright blessed day and dark sacred night, so we may collectively once again be able to think to ourselves, what a wonderful world.