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Can a New DNA Database Help Save This Incredible Sea Turtle?
Hawksbill sea turtles happily flap through the world’s tropical oceans with bellies full of glass-like fragments. Researchers examining the turtles’ digestive tracts would be wise to take care not to slice their hands on shards of the mineral silica that form the skeletons of sea sponges, a mainstay of the hawksbills’ diet. “Few other organisms will eat these sponges,” says José Urteaga, an expert in sea turtle conservation and the director of marine partnerships at Wild Earth Allies, a wildlife conservation group. Named for their bird-like beaks, adult hawksbills can munch an average of around 1,200 pounds of sponges a year. Plucking sponges from the reef prevents the glassy invertebrates from overpopulating and creates gaps in the reef where young corals can attach and grow. “Hawksbills are like the gardeners of coral reefs,” says Urteaga.
Now critically endangered, hawksbill numbers have declined by an estimated 80 percent or more in the last century. Trade of the species was outlawed internationally in 1977, but the robust black market, primarily in Southeast Asia, remains a significant threat to their recovery. Stopping illegal trade is a challenge in part because shells and trinkets are often confiscated in a different country from where turtles are poached, making it difficult to know where protections for the species are most needed. To help untangle this mystery, in 2022 the World Wildlife Fund launched an initiative called ShellBank, which aims to use genetic analysis to trace sea turtle products to their points of origin. ShellBank works by collecting genetic material from illegally traded turtle parts, then comparing those genes with a database of sea turtle DNA collected from individuals in their home waters around the world. By working to establish genetic “fingerprints” unique to each region, investigators hope to match any given mysterious shell’s DNA to its provenance.
So far, the database contains some 13,000 entries for hawksbills and green sea turtles, but the team is hoping to add more sea turtle species and see increased policy and conservation results within the next one or two years, according to Christine Madden, ShellBank’s director and co-founder. Twenty-eight countries are already working with ShellBank or have expressed interest in it, some contributing DNA from seized turtle parts. To date, the program has trained 120 law enforcement officers and 75 local researchers in Southeast Asia to collect, handle and analyze the necessary genetic material. Their shared goal: “We want to use ShellBank to dismantle illegal trade in sea turtles,” Madden says.
Can a New DNA Database Help Save This Incredible Sea Turtle? | Smithsonian
Hungry Sea Otters Are Taking a Bite Out of California’s Invasive Crab Problem, New Study Finds
European green crabs are small, measuring just four inches across. But since they were first introduced in the 1980s, these spiny crustaceans have become a massive problem, wreaking havoc on coastal ecosystems along the western coast of North America. They destroy eelgrass habitats, feast on juvenile salmon and king crab, and outcompete native crabs. In doing so, these invasive critters also pose a threat to the crabbing and fishing industries, which many coastal communities rely on for income.
Now, biologists have identified a new, furry ally in the fight against European green crabs: sea otters. At the Elkhorn Slough National Estuarine Research Reserve in California, hungry southern sea otters (Enhydra lutris nereis) are gobbling up the invasive crabs and keeping their numbers in check, researchers report this month in the journal Biological Invasions.
Scientists believe European green crabs (Carcinus maenas), also known as Joe rocker crabs, first arrived in North America in the early 1800s. They likely caught a ride in the ballast of merchant ships sailing from Europe to the East Coast, according to the National Oceanic and Atmospheric Administration (NOAA). The crustaceans made their way to the West Coast in the 1980s—potentially also in ballast—and have since been spotted in California, Washington, Oregon, Canada and southern Alaska.
European green crabs are not only detrimental to coastal ecosystems, but they’re also extremely difficult to eradicate. States have spent millions of dollars trying to combat the invaders, without much success.
Southern sea otters, meanwhile, were nearly hunted to extinction for their soft, warm fur during the 18th and 19th centuries. Their population plummeted from between 150,000 and 300,000 individuals to a few thousand total individuals by the early 1900s, with just 50 off the coast of central California. But thanks to an international hunting ban in 1911 and the introduction of the Marine Mammal Protection Act in 1972, these charismatic creatures have been making a comeback. Today, an estimated 3,000 southern sea otters live along California’s central coast.
At the Elkhorn Slough National Estuarine Research Reserve, located roughly 20 miles north of Monterey, the first male southern sea otter showed up in the late 1990s. And, starting in the early 2000s, females began arriving. The Monterey Bay Aquarium also released 37 sea otter pups at the reserve, reports USA Today’s Elizabeth Weise. Some 120 individuals now inhabit the tidal estuary—a partially enclosed transitional area featuring both saltwater and freshwater—on California’s Monterey Bay.
Southern sea otters typically eat clams, mussels and sea urchins—and, since they lack blubber, they have to eat a lot to stay warm. But within the reserve, they’ve been happily foregoing these foods and munching on the abundant European green crabs instead. In 2014, for instance, one researcher was astonished to watch a single sea otter devour roughly 30 European green crabs in an hour, per the Washington Post.
“The otters are a just super voracious predator,” says study co-author Kerstin Wasson, an ecologist at the reserve and the University of California, Santa Cruz, to USA Today. “We calculated that the current otter population here eats somewhere between 50,000 and 120,000 green crabs a year.”
In the early 2000s, researchers caught as many as 100 European green crabs in one trap. Today, when they place traps in the same areas, they typically catch fewer than ten of the invaders. They’ve stopped catching large European green crabs altogether.
“I’ve studied green crabs in estuaries on three coasts and two continents for decades, and this is one of the first pieces of good news we’ve gotten,” says Jeppesen in a statement.
Hungry Sea Otters Are Taking a Bite Out of California's Invasive Crab Problem, New Study Finds | Smithsonian
Hawksbill sea turtles happily flap through the world’s tropical oceans with bellies full of glass-like fragments. Researchers examining the turtles’ digestive tracts would be wise to take care not to slice their hands on shards of the mineral silica that form the skeletons of sea sponges, a mainstay of the hawksbills’ diet. “Few other organisms will eat these sponges,” says José Urteaga, an expert in sea turtle conservation and the director of marine partnerships at Wild Earth Allies, a wildlife conservation group. Named for their bird-like beaks, adult hawksbills can munch an average of around 1,200 pounds of sponges a year. Plucking sponges from the reef prevents the glassy invertebrates from overpopulating and creates gaps in the reef where young corals can attach and grow. “Hawksbills are like the gardeners of coral reefs,” says Urteaga.
Now critically endangered, hawksbill numbers have declined by an estimated 80 percent or more in the last century. Trade of the species was outlawed internationally in 1977, but the robust black market, primarily in Southeast Asia, remains a significant threat to their recovery. Stopping illegal trade is a challenge in part because shells and trinkets are often confiscated in a different country from where turtles are poached, making it difficult to know where protections for the species are most needed. To help untangle this mystery, in 2022 the World Wildlife Fund launched an initiative called ShellBank, which aims to use genetic analysis to trace sea turtle products to their points of origin. ShellBank works by collecting genetic material from illegally traded turtle parts, then comparing those genes with a database of sea turtle DNA collected from individuals in their home waters around the world. By working to establish genetic “fingerprints” unique to each region, investigators hope to match any given mysterious shell’s DNA to its provenance.
So far, the database contains some 13,000 entries for hawksbills and green sea turtles, but the team is hoping to add more sea turtle species and see increased policy and conservation results within the next one or two years, according to Christine Madden, ShellBank’s director and co-founder. Twenty-eight countries are already working with ShellBank or have expressed interest in it, some contributing DNA from seized turtle parts. To date, the program has trained 120 law enforcement officers and 75 local researchers in Southeast Asia to collect, handle and analyze the necessary genetic material. Their shared goal: “We want to use ShellBank to dismantle illegal trade in sea turtles,” Madden says.
Can a New DNA Database Help Save This Incredible Sea Turtle? | Smithsonian
Hungry Sea Otters Are Taking a Bite Out of California’s Invasive Crab Problem, New Study Finds
European green crabs are small, measuring just four inches across. But since they were first introduced in the 1980s, these spiny crustaceans have become a massive problem, wreaking havoc on coastal ecosystems along the western coast of North America. They destroy eelgrass habitats, feast on juvenile salmon and king crab, and outcompete native crabs. In doing so, these invasive critters also pose a threat to the crabbing and fishing industries, which many coastal communities rely on for income.
Now, biologists have identified a new, furry ally in the fight against European green crabs: sea otters. At the Elkhorn Slough National Estuarine Research Reserve in California, hungry southern sea otters (Enhydra lutris nereis) are gobbling up the invasive crabs and keeping their numbers in check, researchers report this month in the journal Biological Invasions.
Scientists believe European green crabs (Carcinus maenas), also known as Joe rocker crabs, first arrived in North America in the early 1800s. They likely caught a ride in the ballast of merchant ships sailing from Europe to the East Coast, according to the National Oceanic and Atmospheric Administration (NOAA). The crustaceans made their way to the West Coast in the 1980s—potentially also in ballast—and have since been spotted in California, Washington, Oregon, Canada and southern Alaska.
European green crabs are not only detrimental to coastal ecosystems, but they’re also extremely difficult to eradicate. States have spent millions of dollars trying to combat the invaders, without much success.
Southern sea otters, meanwhile, were nearly hunted to extinction for their soft, warm fur during the 18th and 19th centuries. Their population plummeted from between 150,000 and 300,000 individuals to a few thousand total individuals by the early 1900s, with just 50 off the coast of central California. But thanks to an international hunting ban in 1911 and the introduction of the Marine Mammal Protection Act in 1972, these charismatic creatures have been making a comeback. Today, an estimated 3,000 southern sea otters live along California’s central coast.
At the Elkhorn Slough National Estuarine Research Reserve, located roughly 20 miles north of Monterey, the first male southern sea otter showed up in the late 1990s. And, starting in the early 2000s, females began arriving. The Monterey Bay Aquarium also released 37 sea otter pups at the reserve, reports USA Today’s Elizabeth Weise. Some 120 individuals now inhabit the tidal estuary—a partially enclosed transitional area featuring both saltwater and freshwater—on California’s Monterey Bay.
Southern sea otters typically eat clams, mussels and sea urchins—and, since they lack blubber, they have to eat a lot to stay warm. But within the reserve, they’ve been happily foregoing these foods and munching on the abundant European green crabs instead. In 2014, for instance, one researcher was astonished to watch a single sea otter devour roughly 30 European green crabs in an hour, per the Washington Post.
“The otters are a just super voracious predator,” says study co-author Kerstin Wasson, an ecologist at the reserve and the University of California, Santa Cruz, to USA Today. “We calculated that the current otter population here eats somewhere between 50,000 and 120,000 green crabs a year.”
In the early 2000s, researchers caught as many as 100 European green crabs in one trap. Today, when they place traps in the same areas, they typically catch fewer than ten of the invaders. They’ve stopped catching large European green crabs altogether.
“I’ve studied green crabs in estuaries on three coasts and two continents for decades, and this is one of the first pieces of good news we’ve gotten,” says Jeppesen in a statement.
Hungry Sea Otters Are Taking a Bite Out of California's Invasive Crab Problem, New Study Finds | Smithsonian
@sandiegozoo Wildlife Alliance released 5 ‘alalā, also called Hawaiian crow, in the forests of Maui, Hawaii last month! The birds were hatched and prepared for release under the care of San Diego Zoo Wildlife Alliance at Keauhou Bird Conservation Center. Their approach to conservation breeding incorporates monitoring ‘alalā breeding activity in human care using remote cameras, and an emphasis on allowing parent birds to breed completely on their own. Extinct in the wild since 2002, ‘alalā are the last survivor of all the Hawaiian crow species and were historically found on Hawai‘i Island. Threats to their survival include habitat loss and fragmentation, and predation and disease by introduced species."