Sixteen percent of the species associated with characters in “Finding Nemo” that have been evaluated face the threat of extinction, according to the study, which was conducted by the International Union for Conservation of Nature (IUCN) and Canada’s Simon Fraser University. The analysis of 1,568 species is not just a whimsical look at American popular culture and its cartoon characters. It reveals how humans treat some of the ocean’s most charismatic inhabitants.
“These are species that should be doing better because they are the ones we care about,” said Loren McClenachan, a post-doctoral fellow at Simon Fraser University. She said that highly migratory species such as turtles, sharks and rays are particularly vulnerable to fisheries and other human pressures. “They’ve got life histories that cause them to interact with people wherever they go,” McClenachan said.
The Oscar-winning 2003 Disney/Pixar movie, which details how the clownfish Marlin defies all odds to save his son from the aquarium trade, has a conservation message. But the film actually inspired a booming aquarium trade in the bright orange fish with white stripes, significantly reducing native clownfish populations on coral reefs in Australia and elsewhere.
While the IUCN classifies clownfish as a “species of least concern,” meaning it does not face an imminent extinction risk, 18 percent of the evaluated species that are related to Nemo — those of the scientific family Pomacentridae — are at risk of extinction. There have been few formal scientific assessments of coral reef fish populations that are sought by the aquarium trade, McClenachan said, so “it’s very hard to know the true extent of the aquarium, live reef and curio trade.”
Disney officials could not be reached for comment.
Boris Worm, a marine biologist at Canada’s Dalhousie University who has reviewed the study, which is being published Tuesday in the journal Conservation Letters, said the clownfish boomlet underscores the complex relationship humans have with marine species.
“When people see a beautiful film about tigers, they don’t go out and shoot a tiger. They don’t go out and purchase a tiger,” Worm said in an interview. “In the case of things in the ocean, they think, ‘I care about them, so I’d like to have them,’ or, ‘I care about them, that’s why I’d like to fish them.’ ”
Direct exploitation is the key driver of many of the species’ decline. Many sharks are being targeted to make the Asian delicacy shark fin soup; seahorses are coveted as curios. Other species, such as sea turtles, are vulnerable because they can easily get entangled in commercial fishing gear and because their nesting areas have been trampled or hampered by development.
A survey of the animals with speaking parts in “Finding Nemo” gives a decent sense of how these species are doing. More than half of all hammerhead sharks (personified by “Anchor” in the movie) face a threat of extinction, according to the IUCN, along with all species of marine turtles (“Squirt” and “Crush”).
Those species, McClenachan said, “are more threatened than the most threatened vertebrates on land.”
Neil Hammerschlag, a research assistant professor at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science who studies sharks, said many people are unaware that sharks are under such pressure.
“They are truly the celebrities of the ocean,” Hammerschlag wrote in an e-mail. “Despite their legendary status, most people are unaware that sharks are literally being fished to extinction.”
Nicholas K. Dulvy, who co-authored the study and serves as the Canadian Research Chair in Marine Biodiversity and Conservation, said the group of species he and his colleagues analyzed is not representative of the ocean as a whole. It is “a biased sample, but it’s biased in interesting ways,” he said. Because the movie focuses on coral reefs and areas in the Indo-Pacific, he said, it captures key regions of “the world’s biodiversity.”
In some cases, these populations are beginning to rebound. Nesting populations of marine turtles in Costa Rica increased by more than fivefold between 1971 and 2003, for example, after authorities began protecting nesting females there. And the Convention on Migratory Species’ 116 member parties will ban fishing for giant manta rays and impose measures to safeguard their habitat after the group voted to protect the species.
Dulvy, who also chairs the IUCN Shark Specialist Group, said the paper aims to highlight the “conservation bottleneck” many species face even after researchers have documented their steep population declines. Fewer than 10 percent of the threatened shark and ray species surveyed by the study are protected under the Convention on International Trade of Endangered Species of Wild Fauna and Flora (CITES).
CITES Director-General John E. Scanlon said in a recent interview that his group is working to build political support to protect additional marine species, as well as to raise funds from member nations to support legal enforcement of wildlife trade bans. While many focus on the prospect of how climate change may drive some species out of existence, he said, “All the time we’re planning, we’re losing biodiversity through illegal trade and unsustainable trade of species. Why don’t we deal with the here and now?”
For the four authors of the Nemo paper, focusing on the here and now meant watching the movie four or five times. But Dulvy said he came away with a better impression of the film than when he first saw it eight years ago, especially after watching Bruce the Shark struggle with his pledge to stop eating fish.
“They tried to portray sharks in a way more positive way than is usually done. But they showed them to be fallible, which makes them closer to reality,” he said. “I really enjoyed it.”