Scientists Find Answer to Why Thousands of Sea Lion Pups Are Starving
Scientists finally have an explanation for why so many starving sea lions have been stranded along Southern California's coast in recent years. Their mothers are not getting enough nutritious food.
Last year, more than 3,000 sea lions were found stranded on Southern California beaches, a number higher than the previous five years combined. As of last week, there have been at least 375 sea lion strandings in 2016. Photo credit: NOAA Fisheries West Coast/Flickr
High-fat, high-calorie fish species—namely sardines and anchovies—that female sea lions prefer to feed on have become less abundant where the sea lions commonly hunt near the Channel Islands, National Oceanic and Atmospheric Administration (NOAA) researchers reported Tuesday in the journal Royal Society Open Science.
Instead, female sea lions have had to settle for less nourishing food sources, such as rockfish and market squid. According to the scientists, 81 percent of the change in sea lion pup weights between 2004 and 2013 could be attributed to the decline in sardines and anchovies.
And while the researchers knew that anchovies and sardines become scarce in El Niño years, they wondered whether the effects were limited to only El Niño years.
The Los Angeles Times reported:
To find out, they needed to know where pregnant and nursing sea lions liked to hunt. They estimated a likely foraging range based on the movements of six female sea lions from San Miguel Island that were tagged by researchers in the 1990s. The data from those tags showed they liked to hunt off the California coast between Big Sur and Malibu.
Next they had to figure out what kinds of fish were available in those waters. For more than 30 years, researchers from NOAA's Southwest Fisheries Science Center have been taking a census of young rockfish and other fish species in central California. Data for the area they needed was available from 2004 to 2014.
Finally, they looked up the average weight of 14-week-old sea lion pups from San Miguel Island for each year between 2004 and 2011. During that period, the average weight ranged from 14.8 kilograms to 20.9 kg for female pups and from 17.5 kg to 23.6 kg for male pups.
The pattern they found was clear: When sardines and anchovies were abundant and rockfish and squid were scarce, sea lion pups weighed more. Conversely, when rockfish and squid were plentiful and sardines and anchovies were not, sea lion pups weighed less.
The scientists said they couldn't study “composition or quantity of mothers' milk," and therefore, couldn't make a direct link between the types of fish in the sea and the nutritional value of their milk. However, they said their results "offer compelling evidence" that the sea lion pups are starving because their mothers can't produce adequate amounts of milk.
"Our results refocus the debate on the causes of sea lion pup weight loss from episodic stresses associated with El Niño years to a longer-term trend of declining forage quality in the waters around the California Channel Island rookeries," the scientists concluded.
And the trend is likely to continue. "We expect repeated years with malnourished and starving sea lion pups," they said.
Last year, more than 3,000 sea lions were found stranded on Southern California beaches, a number higher than the previous five years combined. As of last week, there have been at least 375 sea lion strandings in 2016. That's above the average of 160 for the first two months of a typical year, according to NOAA data.
Marine conservation groups, such as Oceana, criticized NOAA for not recognizing the role overfishing has played in causing the sea lion crisis.
U.S. Environmental Protection Agency (EPA) administrator Scott Pruitt met with Dow Chemical CEO Andrew Liveris before deciding to reverse an earlier EPA decision to ban the company's toxic and widely used pesticide, chlorpyrifos.
According to records obtained by the Associated Press, the EPA boss met with Liveris for about 30 minutes at a Houston hotel on March 9. Later that month, Pruitt announced that he would no longer pursue a ban on chlorpyrifos from being used on food, ignoring his agency's own review that even small amounts of the pesticide could impact fetus and infant brain development.
Native communities and environmental justice advocates in Louisiana opened a new resistance camp Saturday to oppose the proposed Bayou Bridge Pipeline project. Called L'eau Est La Vie, or Water is Life, the camp will consist of floating indigenous art structures on rafts and constant prayer ceremonies during its first two weeks.
Continuing its march toward elimination of key Clean Water Act protections, the U.S. Environmental Protection Agency (EPA) on Tuesday issued a formal notice of withdrawal of the Obama administration's rule defining which waters can be protected against pollution and destruction under federal law.
The U.S. Environmental Protection Agency (EPA) is not doing enough to prevent weed resistance to the herbicide glyphosate (Roundup) says a new report from the EPA's Inspector General's Office, which draws in part on a report from the agbiotech company, Pioneer: Weed Management in the Era of Glyphosate Resistance.
When it comes to the latest wind turbine technologies, size matters. A group of six institutions and universities is designing an offshore wind turbine that will stand 500 meters in height. That's taller than the Eiffel Tower and the Empire State Building.
The research team, led by researchers at the University of Virginia, believes that its wind turbine concept will produce 50 megawatts of peak power, or about 10 times more powerful than conventional wind turbines.
Natural gas is often considered the cleanest fossil fuel, but could it actually be dirtier than coal?
Watch as New York Times reporter Mark Bittman, in the above Year's of Living Dangerously video, investigates how much methane is leaking at fracking wells. Find out how the natural gas industry's claims compare to what scientists are reporting.
See what happens when Gaby Petron, an atmospheric scientist with NOAA, converts her van into a mobile methane detector and sets out across northeastern Colorado for two years, taking thousands of readings to uncover the truth.
Adrian Grenier: 'We Must Usher in a New Era of Compassion Through Forward Thinking Environmental Programs'
Adrian Grenier was named UN Goodwill Ambassador earlier this month. The Hollywood actor, best known for his iconic role of A-list movie star Vincent Chase in the HBO smash hit and film Entourage, will advocate for drastically reducing single-use plastic and protection of marine species, and encourage his followers to make conscious consumer choices to reduce their environmental footprint, according to the UN Environment announcement.
"Together we must usher in a new era of compassion and carefulness through forward thinking environmental programs to drive measurable change," Grenier said. "I am personally committed to creating ways in which the global community can come together to help solve our most critical climate crises through routine, collective action.
"The more we connect to nature in our daily lives, the more dedicated we will become to our individual commitments. Together, I believe we can go further, faster in our race to achieve the UN Sustainable Development Goals by 2030."
Watch the video above to learn more.