Saving Nemo: scientists study the animated stars of a classic movie and find that their real-life counterparts are in danger.
The portrayal of ocean life in Finding Nemo--which will be released in 3-D this fall--is scientifically accurate, says Loren McClenachan, an ecologist at Simon Fraser University in British Columbia, Canada, who was involved in the study. Audiences love the animals in Finding Nemo--but are people doing a good job protecting their real-life counterparts?
To find the answer, the team studied more than 1,500 marine species and evaluated their risk of extinction. They chose which species to study by selecting animals with speaking roles in Finding Nemo and then examining the status of every species in their taxonomic families.
"There's this mythology that the oceans are fine and that we don't need to worry about them," says Nick Dulvy, leader of the research team. But 16 percent of the marine animals his group evaluated were threatened with extinction. For many species, not enough information existed to tell if they're in danger. But the scientists suspect that many of those are threatened too.
Information about many of these species is scarce because the ocean is hard to study, says Dulvy. "We can't just see what's going on there. And humans care about what they see." The new study gives a rare glimpse into ocean health.
When Nemo is just an egg, his parents find a new home in the Great Barrier Reef off Australia's northeast coast. Their new home is amongst the tentacles of an animal called a sea anemone. Then a barracuda attacks, and only Nemo and his dad survive.
Nemo and his father are clownfish, part of the family Pomacentridae, a highly diverse marine family with 250 species. Clownfish aren't endangered, but other species in their family--like the Galapagos damsel--are.
One major threat to reef fish like clownfish is climate change. The anemones that they live in grow on coral reefs, which provide homes to one quarter of ocean life. "Coral reefs are possibly the most diverse habitat on the face of the Earth," says Dulvy.
When water temperatures rise a few degrees, corals expel the algae living in them. These algae provide food for the coral, so with the algae gone, the reef dies, and the fish lose their home.
Dory, a reef fish, helps reunite Nemo and his dad. Many species in Dory's family, Acanthuridae, depend on healthy reefs. Scientists don't think her family is in danger of extinction, but they need more information to be sure.
Crush talks like a carefree surfer and spends his days riding ocean currents. He and his son. Squirt. are green sea turtles, and their family, Cheloniidae. is among the best-studied in the ocean.
Six out of seven sea-turtle species are endangered. One reason is that turtles have long migration routes that often put them in contact with humans, says McClenachan. Leatherback turtles, for instance, can travel 16,000 kilometers (10,000 miles) in a single year--that's like swimming from New York to London and back.
Luckily, people are more aware of the need to safeguard turtles, says McClenachan. For example, green-turtle nesting sites on Costa Rica's Tortuguero Beach (which can be translated as "Land of Turtles") have been protected since 1955. As a result 400 percent more green turtles nest there. "Turtles are a really good example of how having knowledge can really turn things around for species that aren't dong so well," says McClenachan.
Mr. Ray, Nemo's teacher, is eager to teach his class all about their coral-reef home. He's a spotted eagle ray, of the family Myliobatidae.
The animals that make up Myliobatidae are mostly large animals that live in the open ocean. They're a mysterious group of creatures that scientists still don't know much about, says Dulvy. In fact, in the past few years, scientists have identified more than 20 new species of large rays and their relatives.
One of the biggest threats to these animals is people. Fishermen hunt rays, for example, for their gills, which the animals use to filter out food from the water. These gills are dried, powdered, and used in traditional Chinese medicines.
For now, scientists have limited data on the Myliobatidaes. But they estimate that species such as manta rays have declined by 30 percent in the past couple of years.
Marlin and Dory are terrified when they meet three sharks. But Bruce and his friends--of the families Sphyrnidae and Lamnidae--turn out to be harmless vegetarians trying hard to remember that "Fish are friends, not food."
Sharks are threatened by people who buy and sell shark fins, which are used to make shark-fin soup, a Chinese delicacy that can sell for $100 per bowl. Some states, like California, Washington, and Oregon, have recently passed laws banning the sale of imported shark fins.
The fishing industry also threatens sharks. Fish such as tuna are caught on long lines baited with thousands of hooks. Fishermen often hook sharks, along with the tuna, as accidental bycatch. All in all, scientists estimate that people kill about 38 million sharks every year.
Recent laws protect sharks in some areas, such as parts of the Bahamas. But sharks have huge ranges, and that makes them hard to protect. "Even when there are laws, they're hard to enforce because the ocean is so big," says McClenachan.
In real-life, sharks aren't vegetarians, but they rarely eat people. There are far more fatal dog attacks than shark attacks.
People are beginning to recognize that sharks aren't bloodthirsty monsters but animals worth protecting. "Things like Finding Nemo have helped shift our perceptions of sharks," says Dulvy.
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|Title Annotation:||BIOLOGY: CONSERVATION|
|Date:||Apr 16, 2012|
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