Whales communicate with other humpbacks via social learning, study shows.
A pair of Humpback whales bubble-net feeding off the coast of western Antarctica.
Photograph by Yva Momatiuk and John Eastcott, Minden Pictures/Corbis
Whether it’s learning a new song, figuring out how to use tools to forage for food, or picking up the local customs, learning from others is an important part of life for many animals, including people.
The idea of a culture or traditions—behavior shared by an identifiable group and acquired through social learning—in cetaceans, a group including whales and dolphins, has been controversial.
But a new study finds strong evidence that a group of humpback whales (Megaptera novaeangliae) in the Gulf of Maine (map) is sharing a newly observed feeding behavior via their social networks. (See related blog: “Sharks Have Social Networks, Learn From Friends.”)
That behavior, called lobtail feeding, was first recorded in one whale in the Gulf of Maine in 1980. Since then, 278 humpback whales—out of about 700 observed individuals that frequent the Stellwagen Bank (map) area—have employed the strategy, according to the study, published this week in the journal Science.
“I’ve been arguing for over a decade now that cultural transmission is important in cetacean societies,” said study co-author Luke Rendell, a marine biologist at the University of St. Andrews in Scotland.
Though he wasn’t surprised the whales traded information, he was surprised at how strongly his data said the whales learned the new feeding strategy socially, rather than because of other factors like having a genetic predisposition to the behavior.
Lobtail feeding is a variation on a technique called bubble-net feeding, which is used by humpbacks around the world.
In bubble-net feeding, a whale blows bubbles into a kind of net surrounding the prey, corralling them into dense schools. Then the whale lunges up through the school with its jaws wide open, scooping up mouthfuls of food. (Watch a video that shows humpbacks bubble-net feeding.)
In lobtail feeding, the humpback slaps the surface of the water one to four times with the underside of its tail before diving down and blowing the bubble net. Rendell speculates the slaps may keep its sand lance prey from jumping out of the water, away from the whale.
“The origin of this behavior was strongly associated with the collapse of herring stocks and a boom in sand lance stock,” said Rendell. So he and his team suggest that lobtail feeding came about when humpbacks switched from hunting herring to catching sand lances, a type of fish.
To track the spread of lobtail feeding in the whale population, the researchers combined data on fisheries stocks with a sampling of a long-term dataset (1980-2007) on humpback whale observations. The data are compiled by trained observers from the Whale Center of New England.
Not only did the use of lobtail feeding increase with corresponding peaks in sand lance populations in the ’80s, Rendell and his colleagues found that knowledge of the new feeding behavior mirrored the loose social connections among the whales.
Basically, a naive whale—an individual who didn’t exhibit lobtailing behavior—was more likely to start lobtailing if it associated with a whale that did use the new technique.
The new study is a good proof of concept showing scientists can use this kind of network analysis in looking at questions of traditions and social learning, said Bennett Galef, a retired professor at McMaster University in Ontario, Canada, who specializes in social learning.
But Galef, who was not involved in the study, cautioned that a behavior can spread through a population without social learning.
It could be that since these animals move around together, they just pick up the same behavior at the same time, said Galef. “That’s not culture.”
Experiments can home in on how information spreads throughout a population better than observational studies can, he added. But Galef acknowledges that you can’t exactly bring whales into a laboratory.
Simon Reader, a behavioral biologist at McGill University in Quebec, Canada, agreed that observational studies can be problematic. For instance, it’s possible there’s an alternate explanation for the spread of lobtail feeding in these humpback whales, he said. “But I think there’s pretty strong evidence for social learning.”
Published April 25, 2013
by Jane J. Lee of National Geographic News
These Invaders Came, Saw, Conquered, and Destroyed
Unknown in the Americas until three decades ago, lionfish—such as the one photographed here near the wreckage of the U.S.S. Schurz in North Carolina—have since been spotted from Rhode Island to Belize. Photograph by Michael Madelung
Aquatic invasive species are plants and animals that evolved in one location and are introduced through a variety of means into another location.
Species have always used the oceans to move about the planet. By swimming or hitching a ride on a log, leaf, or coconut, organisms have found new worlds in which to thrive. But until recently, this process has been moderate, limited by the currents and the winds.
Since humans first took to the seas, though, intrepid stowaways have had ever expanding vehicles for dispersing themselves both faster and farther. The result is an increasing number of ocean ecosystems, primarily near shorelines, that are being compromised or wiped out by non-native species.
What Are They?
An invasive, or non-native, aquatic species can be any organism that exists somewhere in or near water where it doesn’t belong. When an alien species like this arrives in a new location, several things can happen: It can find its new habitat unwelcoming and die off; it can survive with little environmental impact; or it can take over, harming the naturally existing wildlife in a variety of ways.
Invasive species that thrive usually do so because their new habitat lacks natural predators to control their population. They do damage mainly by consuming native species, competing with them for food or space, or introducing disease.
One infamous example is the zebra mussel, accidentally introduced by a cargo ship into the North American Great Lakes from the Black Sea in 1988. The tiny mollusk multiplied uncontrollably, starving out many of the Great Lakes’ native mussel populations and interfering with human structures from factory intake pipes to ship rudders. They’ve now spread from Canada to Mexico and are considered a major nuisance species. Hundreds of millions of dollars are spent annually to control their numbers.
How Do They Get There?
Most marine invasive species stow away in ship ballast. Large boats have tanks in their hulls that are filled with seawater to counterbalance cargo weight. Boats draw in water at their loading port, in some cases more than 20 million gallons (75 million liters). When the ship arrives at its destination, it releases the ballast—along with whatever species happen to be inside, from schools of fish to microscopic organisms. And these days, there’s plenty of opportunity for hitchhiking species. Some 45,000 cargo ships move more than 10 billion tons of ballast water around the world each year.
Invasive species also hitch rides on the outside of ship hulls and on the millions of tons of plastics and other trash that floats around the globe in ocean currents.
Pets acquired through the aquarium and exotic pet trade—and then released—can become invasive species, as can escapees from aquaculture farms.
And ongoing sea temperature rise caused by global warming is allowing non-native species to populate ocean habitats that were once too cold to be hospitable.
To combat invasive species, governments are focusing on how they handle ship ballast. New regulations in a handful of countries require ships to exchange their ballast water while out at sea or treat it to kill stowaway species before they are released.
Posted by National Geographic Society
Amphipod (genus Leucothoe)
When Jim Thomas and his global team of researchers returned to the Madang Lagoon in Papua New Guinea, they discovered a treasure trove of new species unknown to science.This is especially relevant as the research team consisted of scientists who had conducted a previous survey in the 1990s.
“In the Madang Lagoon, we went a half mile out off the leading edge of the active Australian Plate and were in 6,000 meters of water,” said Thomas, Ph.D., a researcher at Nova Southeastern University’s National Coral Reef Institute in Hollywood, Fla. “It was once believed there were no reefs on the north coast of Papua New Guinea since there were no shallow bays and lagoons typical of most coral reef environments. But there was lots of biodiversity to be found.”
Thomas and his team discovered new species of sea slugs (nudibranchs), feather stars (crinoids) and amphipods (genus Leucothoe). There was more variety of these indicator species found than there is in the entire length of Australia’s 1,600-mile Great Barrier Reef.
“This was an astonishing discovery,” Thomas said. “We returned to our labs and began to formally assess our collections. We had no idea this lagoon’s bounty was so profound.”
The international team Thomas led included researchers from and the Scripps Institute of Oceanography in San Diego, the California Academy of Sciences and the National Botanical Gardens of Ireland. Their 3-week expedition ended late last year. While in Madang, they joined a large French contingent of scientists from the Paris Museum of Natural History.
The NSU-led research team’s findings will be shared with the local villagers, as well as regional and federal governments. It will also be published in peer-reviewed journals.
The Madang Lagoon faces many environmental threats by land-based pollution from a recently opened tuna cannery whose outfall is very close to the lagoon’s reefs. “Hopefully, our discoveries will strongly encourage governing bodies to recognize the environmental importance of the lagoon and work to stop the pollution,” Thomas said.
Posted by: Technology Systems Corporation (TSC) in Ocean News and Technology Magazine
What do National Geographic Explorer Dr. Sylvia Earle, Senator Sheldon Whitehouse, Congressman and senate candidate Ed Markey, Ralph Nader, the marine artist Wyland, a syndicated cartoonist, a coast guard admiral, a coastal paddler, the head of America’s largest port and a young woman submarine pilot all have in common? They, along with hundreds of other ocean defenders, will be part of the fourth Blue Vision Summit in Washington D.C. this May 13-16 to send a message to our nation’s leaders – “Now is the time. Our oceans are rising and our voices are too!”
Every two years ocean conservationists of different stripes descend on Washington DC to network and strategize for the “blue movement” and to educate our elected officials to the vital importance our public seas play in assuring the safety, security and stewardship of our maritime nation.
This year’s Blue Vision Summit and 6th annual Peter Benchley Ocean Awards – taking place at the same time – represent both a challenge and hope for our ocean, coasts and the communities that depend on them.
In writing my latest book, The Golden Shore – California’s Love Affair with the Sea I came to realize that in states and places where the public is engaged with the ocean good outcomes for both ecosystems and economies tend to follow. Representative Sam Farr of Monterey has told me that, “California is the one state where you can get elected or lose your job based on your position on coastal protection and offshore oil.” We need to spread that inspiration and fair warning to elected officials from the 49 other states.
This year’s Blue Vision Summit will focus on three major themes: responding to coastal disasters like Super-storm Sandy in ways that will protect the ecosystems that protect us all, making fossil-fuel fired climate change a blue issue and highlighting youth leadership for ocean conservation. We also plan to hold the largest ever Healthy Ocean Capitol Hill Day visits with hundreds of people from across the country meeting directly with their House members, Senators and their staffs on May 15 to let them know we expect them to support the President’s common sense ocean policy for the nation to coordinate and protect our seas while still making sustainable use of them. Also we want Congress to stop slashing the budgets of the nation’s frontline marine agencies including the National Oceanic and Atmospheric Administration and the U.S. Coast Guard. We’ll also be encouraging Congress to support bills that fight both seafood fraud and illegal pirate fishing. This is something we’re obliged to do as citizens and legally permitted to do as non-profit educational groups, activists, businesspeople, scientists and youths.
Among the most active participants we’re expecting will be high school and college students who are planning marine science and maritime careers while finding new ways to protect the ocean they love. They are coming from New York, California, Florida and other places, even Colorado because at 5,000 feet above sea level the group Teens4Oceans understands that, “every state is a coastal state.”
The hope for ocean conservation will also be reflected in this year’s outstanding Peter Benchley Ocean Award winners. The world’s leading marine conservation awards the Benchleys are named after Peter Benchley because, while most people know he wrote the novel ‘Jaws’, few are aware that this prolific author spent most of his life working to protect sharks and other marine wildlife.
This year’s winners include President Macky Sall of Senegal, a West African head of state who has banned foreign fishing fleets from his nation’s waters, ocean scientists Boris Worm and Heike Lotze from Canada who are expanding the world’s knowledge of marine ecology, Representative Ed Markey, a long time ocean champion from Massachusetts who takes no guff from saltwater special interests, Nancy Baron and COMPASS, a long-time ocean communicator and her organization that help translate ocean science into public understanding, Sean Russell, a young man from Florida who has challenged recreational fishermen and women to clean up after themselves by providing safe disposal systems for fishing line and two California women, Karen Garrison and Kaitilin Gaffney, who effectively have helped move the state’s park system into the water column by protecting 16 percent of state waters as marine reserves. This year will also mark the largest gathering of past and present winners including Dr. Jane Lubchenco, the recently retired head of NOAA, Washington Post reporter and shark author Juliet Eilperin and 2010 youth winner and anti-plastics activist Rudy Sanchez.
Seaweed (marine grassroots) activists and ocean lovers are invited to attend this year’s Blue Vision Summit to help turn the tide for our ocean planet and restore the blue in our red, white and blue. Given the cascading disasters that still threaten our living seas including industrial overfishing, pollution, coastal sprawl and climate change we’re not sure if we can win the fight to restore our public seas. All we do know for certain is that if we don’t show up for the fight we lose.
For more information on BVS4 & PBOA6 go to: http://www.bluefront.org/blue_vision_blog/2013-summit/
Posted by David Helvarg on April 15, 2013
Mbari1Major faults within the California Borderland. Image © 2013 MBARI. Base map from Google Maps.
Hidden beneath ocean waves and masked by sand and mud on the seafloor, underwater faults are notoriously difficult to see and even more difficult to study. As a result, geologists struggle to evaluate the risks associated with these faults and often can’t include them in seismic hazard assessments.
“People have known that a significant portion of plate motion is going on offshore, but because there have been no techniques to get at this, it’s something that is totally left out of the hazard assessments,” said MBARI geologist Charlie Paull.
Now, with improved technology available for underwater imaging, Paull and his colleagues at the U.S. Geological Survey have brought some of these hidden faults into view for the first time. The resulting data could help coastal residents better prepare for seismic threats.
Paull’s team conducted their studies off the coast of Southern California, in a region called the California Borderland, which extends from Baja California to Point Conception. They collected ultra-high-resolution images of the seafloor using one of MBARI’s autonomous underwater vehicles (AUVs). They then used these images to measure the slip rate—the rate at which two pieces of crust slide past each other—within a region of the Borderland called the San Diego Trough Fault Zone. This marks the first slip rate that has ever been recorded for an offshore fault within the California Borderland. The team reported their findings in the December 2012 Bulletin of the Seismological Society of America.
The San Diego Trough Fault Zone runs roughly from the Mexican border northward toward Catalina Island. To calculate the fault’s slip rate, the researchers first used data from MBARI’s seafloor-mapping AUV to measure how far the fault had shifted the seafloor. They looked, particularly, at the walls of an ancient and inactive underwater channel, and found a shift of about 18 meters.
To estimate how long this 18-meter shift took to form, the team used high-resolution sub-bottom profiles from MBARI’s AUV to look beneath the seafloor and measure the thickness of the muddy layers of sediment. They also collected samples of this sediment using MBARI’s remotely operated vehicle (ROV) Doc Ricketts. Based on populations of tiny animals at different depths in the sediment samples, the researchers estimated that the sediment had been accumulating for about 12,000 years since the channel had stopped eroding. Assuming that erosion in the channel would have been powerful enough to erase remnants of shifting, the team concluded that the 18-meter offset occurred within the 12,000 years after the channel had stopped eroding.MBARI2
A portion of the San Diego Trough Fault Zone that bisects an ancient seafloor channel called the San Gabriel Channel. The inset shows aclose-up of the channel wall that has been offset by the fault, with white arrows indicating the direction of slip between the two plates. Image © 2013 MBARI.
By dividing the total offset distance (18 meters) by the age of the offset (12,000 years), the researchers calculated an average slip rate of roughly 1.5 millimeters per year. Although this is a relatively small portion of the total eight millimeters of slip per year estimated for all offshore faults in the California Borderland, it is still enough to generate small to moderate earthquakes.
In fact, based on their study, the team concluded that the San Diego Trough Fault Zone may have spawned the 1986 Oceanside earthquake—a magnitude 5.4 quake that caused nearly one million dollars in damage, 29 injuries, and one death.
“The coupled use of MBARI’s assets—the mapping AUV which can show us exactly where the faults are and the ROV that allows us to go down there and sample in a really surgical way—allows us to start doing the type of basic land-surface science…that goes into a seismic hazard assessment,” said Paull.
Paull emphasized that the team’s methods were very similar to those used to study faults on land, but that this was among the first studies to take the same types of measurements underwater.
Using their new sonar data, the team also discovered that this fault extends 60 kilometers (37 miles) further north than previously mapped. It may even be linked to the San Pedro Basin Fault Zone, which extends an additional 90 kilometers to the northwest. If this is the case, this fault zone would be one of the longest in the California Borderland, and could produce some of the largest earthquakes in the region.
“It would be one of the biggest [faults] of Southern California, probably second to the San Andreas,” said Paull.
Given the abundance of underwater faults in the California Borderland, and their proximity to the San Onofre Nuclear Generating Station, Paull believes these research methods will be used more frequently in the region in the coming years.
“I think we are going to see a lot more of this done in the future,” he said.
Posted By: Ocean News & Technology