The fate of the world's great whale species commands global attention as a result of heated debate between pro and anti-whaling advocates, but the fate of smaller marine mammals is less understood, specifically because the deliberate and accidental harvesting of dolphins, porpoises, manatees and other warm-blooded aquatic denizens is rarely studied or monitored. To shed more light on the issue, researchers from the Wildlife Conservation Society and Okapi Wildlife Associates have conducted an exhaustive global study of human consumption of marine mammals using approximately 900 sources of information.

The main finding: since 1990, people in at least 114 countries have consumed one or more of at least 87 marine mammal species. In addition to this global review, Wildlife Conservation Society scientists work in remote countries around the world to assess and actively address the threat to dolphin populations with localized, applied conservation efforts.

The new global study appears in the most recent edition of Biological Conservation. The authors include: Dr. Martin D. Robards of the Wildlife Conservation Society; and Dr. Randall R. Reeves of Okapi Wildlife Associates.

"International bodies such as the International Whaling Commission were formed specifically to gauge the status of whale populations and regulate the hunting of these giants," said Robards, lead author of the new study. "These species, however, represent only a fraction of the world's diversity of marine mammals, many of which are being accidentally netted, trapped, and -- in some instances -- directly hunted without any means of tracking as to whether these harvests are sustainable."

In order to build a statistically robust picture of human consumption rates of marine mammals around the world, Robards and Reeves started with records on small fisheries focused on small whales (i.e. pilot whales), dolphins, and porpoises from 1975 and records of global marine mammal catches between 1966 and 1975. From there, the authors consulted some 900 other sources and consulted with numerous researchers and environmental managers, an exhaustive investigation that took three years to complete. The team only counted information with actual evidence of human consumption of marine mammals, omitting instances where marine mammals were caught (either intentionally or not) for fishing bait, feed for other animals, medicines, and other uses.

The list of marine mammals killed for human consumption includes obscure species such as the pygmy beaked whale, the South Asian river dolphin, the narwhal, the Chilean dolphin, the long-finned pilot whale, and Burmeister's porpoise. Seals and sea lions are on the list as well, including species such as the California sea lion and lesser known species such as the Baikal seal. The polar bear (a bear that is considered a marine mammal) also makes the list. Three species of manatee and its close relative the dugong, considered a delicacy in some parts of the world, are also widespread targets of human consumption.

Overall, the historical review reveals an escalation in the utilization of smaller cetaceans, particularly coastal and estuarine species since 1970, often caught as accidental "bycatch" in nets meant for fish and other species. Once caught, however, small cetaceans are being increasingly utilized as food in areas of food insecurity and/or poverty, what the authors call "fishing up the food chain."

"Obviously, there is a need for improved monitoring of species such as the Atlantic and Indo-Pacific humpback dolphins and other species," said Dr. Howard Rosenbaum, Director of WCS's Ocean Giants Program. "In more remote areas and a number of countries, a greater immediate need is to understand the motivations behind the consumption of marine mammals and use these insights to develop solutions to protect these iconic species that lead to more effective management and conservation."

WCS's Ocean Giants Program works in a number of seascapes of critical importance to small cetaceans in particular. These efforts are focused on the local level to address local impacts on coastal dolphin populations, providing on-the-ground practical conservation actions to compliment the global investigative work highlighted above.

In Congo, Gabon, and Madagascar, WCS conservation scientists Dr. Salvatore Cerchio and Tim Collins are conducting scientific studies to assess the status of impacted dolphin populations, and work with local communities of traditional fishermen to reduce accidental bycatch and deliberate hunting of dolphins. In these regions, the scientists are documenting a worrying trend in increased captures and use of dolphins for food, and they are sometimes also being sold in markets better known for their association with terrestrial bushmeat.

In response, Cerchio and the WCS Madagascar team have worked with local communities to establish a local conservation association composed of fishermen, local traditional laws protecting dolphins, and development of community-based whale and dolphin watching as an alternative livelihood. On the other side of the African continent, the coasts of Gabon and Congo represent one of the last strongholds for the rare Atlantic humpback dolphin. Catches by fishermen in Gabon are extremely rare, but groups of dolphins that cross the border (a finding of recent WCS work) risk capture in coastal gillnets set by artisanal fisherman. "The Atlantic humpback dolphin may well be the rarest mammal in the Congo basin region," said Tim Collins. "Unfortunately, few have ever heard of it, least of all the fisherman eating them out of existence."

Text by Wildlife Conservation Society Photo by NOAA

Rising human carbon dioxide emissions may be affecting the brains and central nervous system of sea fishes with serious consequences for their survival, an international scientific team has found.

Carbon dioxide concentrations predicted to occur in the ocean by the end of this century will interfere with fishes' ability to hear, smell, turn and evade predators, says Professor Philip Munday of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

"For several years our team have been testing the performance of baby coral fishes in sea water containing higher levels of dissolved CO2 -- and it is now pretty clear that they sustain significant disruption to their central nervous system, which is likely to impair their chances of survival," Prof. Munday says.

In their latest paper, published in the journal Nature Climate Change, Prof. Munday and colleagues report world-first evidence that high CO2 levels in sea water disrupts a key brain receptor in fish, causing marked changes in their behavior and sensory ability.

"We've found that elevated CO2 in the oceans can directly interfere with fish neurotransmitter functions, which poses a direct and previously unknown threat to sea life," Prof. Munday says.

Prof. Munday and his colleagues began by studying how baby clown and damsel fishes performed alongside their predators in CO2-enriched water. They found that, while the predators were somewhat affected, the baby fish suffered much higher rates of attrition.

"Our early work showed that the sense of smell of baby fish was harmed by higher CO2 in the water -- meaning they found it harder to locate a reef to settle on or detect the warning smell of a predator fish. But we suspected there was much more to it than the loss of ability to smell."

The team then examined whether fishes' sense of hearing -- used to locate and home in on reefs at night, and avoid them during the day -- was affected. "The answer is, yes it was. They were confused and no longer avoided reef sounds during the day. Being attracted to reefs during daylight would make them easy meat for predators."

Other work showed the fish also tended to lose their natural instinct to turn left or right -- an important factor in schooling behavior which also makes them more vulnerable, as lone fish are easily eaten by predators.

"All this led us to suspect it wasn't simply damage to their individual senses that was going on -- but rather, that higher levels of carbon dioxide were affecting their whole central nervous system."

The team's latest research shows that high CO2 directly stimulates a receptor in the fish brain called GABA-A, leading to a reversal in its normal function and over-excitement of certain nerve signals.

While most animals with brains have GABA-A receptors, the team considers the effects of elevated CO2 are likely to be most felt by those living in water, as they have lower blood CO2 levels normally. The main impact is likely to be felt by some crustaceans and by most fishes, especially those which use a lot of oxygen.

Prof. Munday said that around 2.3 billion tonnes of human CO2 emissions dissolve into the world's oceans every year, causing changes in the chemical environment of the water in which fish and other species live.

"We've now established it isn't simply the acidification of the oceans that is causing disruption -- as is the case with shellfish and plankton with chalky skeletons -- but the actual dissolved CO2 itself is damaging the fishes' nervous systems."

The work shows that fish with high oxygen consumption are likely to be most affected, suggesting the effects of high CO2 may impair some species worse than others -- possibly including important species targeted by the world's fishing industries.

Text and Photo by ARC Centre of Excellence in Coral Reef Studies

Every year, a group of anti-whaling nonprofit organizations that includes Greenpeace, Sea Shepherd, and the World Wildlife Fund spend, by conservative estimates, some $25 million on a variety of activities intended to end commercial whaling. And every year, commercial whaling not only continues, but grows.

Under the current, largely unregulated system, the number of whales harvested annually has doubled since the early 1990s, to about two thousand per year. Further, many populations of large whales have been severely depleted and continue to be threatened by commercial whaling.

While protests, education, lobbying and dangerous confrontations on the high seas have saved some whales, the whaling industry shows no sign of shutting down -- or slowing down.

Now, an economist and two marine scientists writing in the January 12 issue of the journal Nature suggest a new strategy that they believe could save whales by putting a price on them.

In the article, "A market approach to saving the whales," Christopher Costello and Steve Gaines, professors of economics and marine science, respectively, at the Bren School of Environmental Science & Management at the University of California, Santa Barbara, join Leah Gerber, a population ecologist and marine conservation biologist at Arizona State University, to propose a market-based solution to saving whales.

"We propose an alternative path forward that could break the deadlock: quotas that can be bought and sold, creating a market that would be economically, ecologically, and socially viable for whalers and whales alike," the authors write.

"The authors have put forth some bold, fresh thinking aimed at a barbaric practice that has become an intractable problem," said The Nature Conservancy California Executive Director Mike Sweeney.

The idea has its roots in trading markets for such air pollutants as sulfur dioxide and nitrogen oxides, which have reduced pollutants more and at a lower cost in the U.S. than resulted from traditional regulatory policy; conservation and wetland management programs, which have resulted in more than 200,000 acres of land being set aside; and individual transferable quotas, which have been successful in sustaining fisheries and fishermen in New Zealand, Iceland, and Canada.

The authors explain that the concept of auctioning off annual whale-catch quotas was suggested as early as 1982 but was never implemented, perhaps, they suggest, because whalers would have had to purchase something they had always received for free. They add that a "whale-conservation market," would be different, with "whale shares" being allocated in sustainable numbers to all members of the International Whaling Commission. Recipients could then exercise them (by harvesting their quota), hold onto them for a year, or permanently retire them. The shares would be tradable in a carefully controlled global market.

In the two most extreme scenarios, whalers could end up purchasing all the shares and harvesting whales at the established sustainable level, or conservationists might purchase all the shares, so that no whales would be harvested.

"Because conservationists could bid for quotas, whalers could profit from them even without harvesting the animals," the professors say. And while they concede that "there are multiple challenges in getting such a scheme to work, including agreeing on sustainable quotas and on how shares should be allocated," they do not see those obstacles as insurmountable.

But would whalers settle for quotas? In fact, the authors say, whaling nations have previously proposed quotas, which would legitimize their harvest. Many anti-whaling groups, on the other hand, have had a fundamental problem with setting quotas for the same reason, feeling that quotas would appear to legitimize commercial whaling.

"If quotas are set properly," the authors suggest, "transactions would reduce the number of whales harvested, quite possibly to zero, unlike existing protocols, which seem to be increasing the catches."

They conclude: "The fervent anti-whaler will be quick to argue you cannot and should not put a price on the life of a whale; a species should be protected irrespective of its economic value. But unless all nations can be convinced or forced to adopt this view, whaling will continue. It is precisely because of the lack of a real price tag in the face of different values that anti-whaling operations have had such limited success.... By placing an appropriate price tag on the life of a whale, a whale conservation market provides an immediate and tangible way to save them."

Text by University of California - Santa Barbara Photo by NOAA

Nature's game of intimidation and imitation comes full circle in the waters of Indonesia, where scientists have recorded for the first time an association between the black-marble jawfish (Stalix cf. histrio) and the mimic octopus (Thaumoctopus mimicus).

Undescribed by scientists until 1998, the talented mimic octopus is known to impersonate toxic flatfish, lionfish, and even sea snakes by creatively configuring its limbs, adopting characteristic undulating movements, and displaying bold brown-and-white color patterns. Thanks to these brazen habits, it can swim in the open with relatively little fear of predators.

The jawfish, on the other hand, is a small and timid fish. It spends most of its adult life close to a sand burrow, where it will quickly retreat upon sighting a predator.

During a diving trip in Indonesia in July 2011, Godehard Kopp of the University of Gottingen, Germany, filmed an unexpected pairing between the two animals. Like a lackey clinging on to the big man on campus, the black-marble jawfish was seen closely following a mimic octopus as it moved across the sandy bottom. The jawfish had brown-and-white markings similar to the octopus, and was difficult to spot among the many arms. The octopus, for its part, did not seem to notice or care.

Kopp sent the video to Rich Ross and Luiz Rocha of the California Academy of Sciences, who identified the jawfish species. Since this association had not been recorded before, they published their observations online last month in the scientific journal Coral Reefs. The authors surmise that the jawfish hitches a ride with the octopus for protection, allowing it to venture away from its burrow to look for food -- a case of "opportunistic mimicry."

"This is a unique case in the reefs not only because the model for the jawfish is a mimic itself, but also because this is the first case of a jawfish involved in mimicry," said Dr. Luiz Rocha, assistant curator of ichthyology at the California Academy of Sciences. "Unfortunately, reefs in the Coral Triangle area of southeast Asia are rapidly declining mostly due to harmful human activities, and we may lose species involved in unique interactions like this even before we get to know them."

Text and Video by California Academy of Sciences

Debris from the tsunami that devastated Japan in March could reach the United States as early as this winter, according to predictions by NOAA scientists. However, they warn there is still a large amount of uncertainty over exactly what is still floating, where it's located, where it will go, and when it will arrive. Responders now have a challenging, if not impossible situation on their hands: How do you deal with debris that could now impact U.S. shores, but is difficult to find?

To learn more about the tsunami debris, NOAA researchers have been working with the U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, and other partners to coordinate data collection activities.

NOAA and its partners are also coordinating an interagency assessment and response plan to address the wide-range of potential scenarios and threats posed by the debris.

"We're preparing for the best and worst case scenarios -- and everything in between," says Nancy Wallace, director for NOAA's Marine Debris Program.

As the tsunami surge receded, it washed much of what was in the coastal inundation zone into the ocean. Boats, pieces of smashed buildings, appliances, and plastic, metal, and rubber objects of all shapes and sizes washed into the water -- either sinking near the shore or floating out to sea. The refuse formed large debris fields captured by satellite imagery and aerial photos of the coastal waters.

The Japanese government estimated that the tsunami generated 25 million tons of rubble, but there is no clear understanding of exactly how much debris was swept into the water nor what remained afloat.

What remains of the debris?

Nine months later, debris fields are no longer visible. Winds and ocean currents scattered items in the massive North Pacific Ocean to the point where debris is no longer visible from satellite. Vessels regularly traveling the North Pacific have reported very few sightings. Only two pieces have been clearly linked to the tsunami.

NOAA is coordinating new interagency reporting and monitoring efforts that will provide critical information on the location of the marine debris generated by the tsunami. Ships can now report significant at-sea debris sightings and individuals or groups can request shoreline monitoring guides at DisasterDebris@noaa.gov.

Where is it?

Computer models run by NOAA and University of Hawaii researchers show some debris could pass near or wash ashore in the Northwestern Hawaiian Islands (in the Papahnaumokukea Marine National Monument) as early as this winter, approach the West Coast of the United States and Canada in 2013, and circle back to the main Hawaiian Islands in 2014 through 2016.

Researchers caution that models are only predictions based on location of debris when it went into the water, combined with historical ocean currents and wind speeds.

Conditions in the ocean constantly change, and items can sink, break down, and disperse across a huge area. Because it is not known what remains in the water column nor where, scientists can't determine with certainty if any debris will wash ashore.

Worst- and Best-case Scenarios

The worst-case scenario is boats and unmanageable concentrations of other heavy objects could wash ashore in sensitive areas, damage coral reefs, or interfere with navigation in Hawaii and along the U.S. West Coast. Best case? The debris will break up, disperse and eventually degrade, sparing coastal areas.

Debris will not go away completely, even in a best-case scenario. Marine debris is an ongoing problem for Hawaii and West Coast states, where garbage and other harmful items regularly wash up on beaches, reefs and other coastal areas.

Text and Graphic by National Oceanic and Atmospheric Administration

In 2011, researchers at the California Academy of Sciences added 140 new relatives to our family tree. The new species include 72 arthropods, 31 sea slugs, 13 fishes, 11 plants, nine sponges, three corals, and one reptile. They were described by more than a dozen Academy scientists along with several dozen international collaborators.

Proving that there are still plenty of places to explore and things to discover on Earth, the scientists made their finds over six continents (all except Antarctica) and three oceans (Atlantic, Pacific, and Indian), climbed to the tops of mountains and descended to the bottom of the sea, looked in their owns backyards (California) and on the other side of the world (Cameroon).

Their results, published in 33 different scientific papers, add to the record of life on Earth and help advance the Academy's research into two of the most important scientific questions of our time: "How did life evolve?" and "How will it persist?"

Discovering new species, formally describing them, and determining their evolutionary relationships to other organisms provide the crucial foundation for making informed conservation decisions at a national level. For example, earlier this year, Academy scientists embarked on the largest expedition in the institution's recent history -- a 42-day journey to the Philippines to survey the shallow water, deep sea, and mountain habitats of Luzon Island. Early estimates indicate that they may have discovered as many as 500 new species. While it takes months and even years to formally describe and publish a new species in a peer-reviewed scientific journal (the reason they are not included in the 2011 total), Academy scientists had enough initial data to provide a formal recommendation to Conservation International and the Philippine government outlining the most important locations for establishing or expanding marine protected areas. Formal species descriptions in the coming years should help the scientists bolster and refine their initial recommendations.

Below are a few highlights among the 140 species described by the Academy this year. For a full list of species, including geographic information, visit here.

Four New Sharks
Academy research associate David Ebert and his colleagues described four new species of deep-sea sharks this year. The African dwarf sawshark (Pristiophorus nancyae) was collected via a bottom trawl at a depth of 1,600 feet, off the coast of Mozambique. It is notable for its elongated blade-like snout, or "rostrum," which is studded with sharp teeth and used as a weapon. The sawshark will swim through a school of fish swinging its rostrum back and forth, stunning and injuring prey, and then swim back to consume the casualties. Ebert and his colleagues also described two species of lanternshark: Etmopterus joungi from a fish market in Taiwan, and Etmopterus sculptus from trawling at depths of 1,500 -- 3,000 feet off the coast of southern Africa. Like their name suggests, lanternsharks emit light on various parts of their body -- probably a strategy to camouflage themselves from upward-looking predators and also to interact with others of their own species. Finally, a new species of angel shark (Squatina caillieti) was described from a single specimen collected in 1,200 feet of water off the Philippine island of Luzon. Angel sharks have flattened bodies and large pectoral fins resembling wings.

A Bounty of Arthropods
There are more species of arthropods -- insects, spiders, crustaceans, and other joint-legged creatures -- than any other group of animals on Earth, and more are being discovered every day. So it's no surprise that over half of the new species on this year's list consists of arthropods: 43 ants, 20 goblin spiders, six barnacles, and three beetles. In addition, Academy scientists took it to the next level -- literally -- by describing six new genera ("genus" being one classification level higher than "species"). These include three new genera of goblin spiders from Africa (Malagiella, Dalmasula, Molotra) and three new genera of barnacles (Minyaspis, Pycnaspis, and the fossil Archoxynaspis).

Gorgeous Sea Slugs
Despite the common name of "sea slug," nudibranchs are breathtaking in their beauty and diversity. Every color of the rainbow is represented among nudibranchs, in a wide variety of patterns, making them a favorite for underwater photographers. These animals use color as a warning sign -- predators learn to associate their vivid colors with their toxic or unpalatable nature, and so they avoid eating them.

More than 3,000 nudibranch species have been discovered and described to date, and scientists estimate that another 3,000 species are yet to be named. Academy Dean of Science Terry Gosliner and his colleagues did their part to increase our knowledge of nudibranch diversity by describing 31 new species this year, from places as close as Florida to faraway countries like Papua New Guinea.

Text and Photo by California Academy of Sciences

A new study examining the complex and dynamic interactions between white sharks and Cape fur seals in False Bay, South Africa, offers new insights on the physical conditions and biological factors underlying predator-prey interactions in the marine environment.

University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science assistant professor Dr. Neil Hammerschlag, and a colleague from the University of British Columbia, describe how sharks are camouflaged as they stalk their prey from below. Low-light conditions, from the optical scattering of light through water, along with a shark's dark grey back and the dimly light rocky reef habitat allow sharks to remain undetected by seals swimming at the water's surface.

"Animal hunting in the ocean is rarely observed by humans," said Hammerschalg, director of the RJ Dunlap Marine Conservation Program at UM. "The high frequency of attacks by white sharks on seals at our study site in South Africa provides a very unique opportunity to uncover new insights about predator-prey relationships."

Sharks typically search, stalk and strike their prey from below. The vast majority of predatory strikes by sharks and Cape fur seals occur against small groups of young-of-the-year seals. Predatory activity by sharks is most intense within two hours of sunrise and quickly decreases as light penetration in the water column increases.

"Stealth and ambush are key elements in the white shark's predatory strategy," said Hammerschlag.

Cape fur seals also have unique techniques to detect, avoid, outmaneuver and in some cases injure the white shark in order to avoid predation by sharks.

According to the authors, if a seal is not disabled during the shark's initial shark, the small seal can use its highly maneuverable body to leap away from the shark's jaws to evade a second strike.

Text by University of Miami Rosenstiel School of Marine & Atmospheric Science Photo by N. Hammerschlag

South Australian Museum and University of Adelaide scientists working on fossils from Kangaroo Island have found eyes belonging to a giant 500 million-year-old marine predator that sat at the top of Earth's first food chain.

This story will be accompanied by an artist's impression of the super predator on the front cover of the 8 December 2011 issue of Nature.

Palaeontologists have discovered exceptionally preserved fossil eyes of the top predator in the Cambrian ocean from over 500 million years ago: the fearsome meter-long Anomalocaris.

The scientists show that the world's first apex predator had highly acute vision, rivaling or exceeding that of most living insects and crustaceans.

The international team behind this discovery includes two Adelaide researchers, Dr Michael Lee (SA Museum and University of Adelaide -- Environment Institute and School of Earth & Environmental Sciences) and Dr Jim Jago (SA Museum and UniSA), and was led by Dr John Paterson (University of New England).

The World's Oldest Apex Predator

Anomalocaris is the stuff of nightmares and sci-fi movies. It is considered to be at the top of the earliest food chains because of its large body size, formidable grasping claws at the front of its head and a circular mouth with razor-sharp serrations.

Supporting evidence of this predator's dominance includes damage to contemporaneous trilobites, and even its fossilized poo (or coprolites) containing the remains of its prey.

The discovery of its stalked eyes -- showing astonishing details of its optical design -- from a 515 million-year-old deposit on Kangaroo Island in South Australia now confirms it had superb vision to support its predatory lifestyle.

All The Better To See You With...

The fossils represent compound eyes -- the multi-faceted variety seen in arthropods such as flies, crabs and kin -- and are amongst the largest to have ever existed, with each eye up to 3 cm in length and containing over 16,000 lenses.

The number of lenses and other aspects of their optical design suggest that Anomalocaris would have seen its world with exceptional clarity whilst hunting in well-lit waters. Only a few arthropods, such as modern predatory dragonflies, have similar resolution.

The existence of highly sophisticated, visual hunters within Cambrian communities would have accelerated the predator-prey 'arms race' that began during this important phase in early animal evolution over half a billion years ago.

The discovery of powerful compound eyes in Anomalocaris confirms it is a close relative of arthropods, and has other far-reaching evolutionary implications. It demonstrates that this particular type of visual organ appeared and was elaborated upon very early during arthropod evolution, originating before other characteristic anatomical structures of this group, such as a hardened exoskeleton and walking legs.

Text by University of Adelaide Illustration by Katrina Kenny

Researchers have discovered that the destructive tsunami generated by the March 2011 Thoku-Oki earthquake was a long-hypothesized "merging tsunami" that doubled in intensity over rugged ocean ridges, amplifying its destructive power before reaching shore.

Satellites captured not just one wave front that day, but at least two, which merged to form a single double-high wave far out at sea -- one capable of traveling long distances without losing its power. Ocean ridges and undersea mountain chains pushed the waves together, but only along certain directions from the tsunami's origin.

The discovery helps explain how tsunamis can cross ocean basins to cause massive destruction at some locations while leaving others unscathed, and raises hope that scientists may be able to improve tsunami forecasts.

At a news conference Dec. 5 at the American Geophysical Union meeting in San Francisco, Y. Tony Song, a research scientist at NASA's Jet Propulsion Laboratory (JPL); and C.K. Shum, professor and Distinguished University Scholar in the Division of Geodetic Science, School of Earth Sciences at Ohio State University, discussed the satellite data and simulations that enabled them to piece the story together.

"It was a one-in-ten-million chance that we were able to observe this double wave with satellites," said Song, the study's principal investigator. "Researchers have suspected for decades that such 'merging tsunamis' might have been responsible for the 1960 Chilean tsunami that killed many in Japan and Hawaii, but nobody had definitively observed a merging tsunami until now."

"It was like looking for a ghost," he continued. "A NASA/French Space Agency satellite altimeter happened to be in the right place at the right time to capture the double wave and verify its existence."

Shum agreed. "We were very lucky, not only in the timing of the satellite, but also to have access to such detailed GPS-observed ground motion data from Japan to initiate Tony's tsunami model, and to validate the model results using the satellite data. Now we can use what we learned to make better forecasts of tsunami danger in specific coastal regions anywhere in the world, depending on the location and the mechanism of an undersea quake."

The NASA/Centre National d'Etudes Spaciales Jason-1 satellite passed over the tsunami on March 11, as did two other satellites: the NASA/European Jason-2 and the European Space Agency's EnviSAT. All three carry a radar altimeter, which measures sea level changes to an accuracy of a few centimeters.

Each satellite crossed the tsunami at a different location. Jason-2 and EnviSAT measured wave heights of 20 cm (8 inches) and 30 cm (12 inches), respectively. But as Jason-1 passed over the undersea Mid-Pacific Mountains to the east, it captured a wave front measuring 70 cm (28 inches).

The researchers conjectured ridges and undersea mountain chains on the ocean floor deflected parts of the initial tsunami wave away from each other to form independent jets shooting off in different directions, each with its own wave front.

The sea floor topography nudges tsunami waves in varying directions and can make a tsunami's destruction appear random. For that reason, hazard maps that try to predict where tsunamis will strike rely on sub-sea topography. Previously, these maps only considered topography near a particular shoreline. This study suggests scientists may be able to create maps that take into account all undersea topography, even sub-sea ridges and mountains far from shore.

Song and his team were able to verify the satellite data through model simulations based on independent data, including the GPS data from Japan and buoy data from the National Oceanic and Atmospheric Administration's Deep-ocean Assessment and Reporting of Tsunamis program.

"Tools based on this research could help officials forecast the potential for tsunami jets to merge," said Song. "This, in turn, could lead to more accurate coastal tsunami hazard maps to protect communities and critical infrastructure."

Text by Ohio State University Graphic by NASA

Engineers at Virginia Polytechnic Institute and State University (VirginiaTech) have developed a robot that mimics the graceful motions of jellyfish so precisely that it has been named Robojelly. Developed for the U.S. Office of Naval Research in 2009, this vehicle was designed to conduct ocean underwater surveillance, enabling it potentially to detect chemical spills, monitor the presence of ships and submarines, and observe the migration of schools of fish.

Recently, a team at VirginiaTech has improved the performance of this silicone swimmer, enabling it to better overcome the limitations of its artificial skin and better mimic the true motion of a jellyfish. Details on this new design and how it might provide new insights into jellyfish propulsion mechanisms are being presented at the 2011 meeting of the American Physical Society's Division of Fluid Dynamics in Baltimore, Md., Nov. 20-22.

According to VirginiaTech mechanical engineer Alex Villanueva, Robojelly looks very similar to an actual jellyfish. "Its geometry is copied almost exactly from a moon jellyfish [Aurelia aurita]," he said. The robot is built out of silicone and uses shape memory alloy (SMA) actuators to swim.

To move through the water, the natural animal uses the bell section of its body, which deforms and contracts to provide thrust. The lower, or lagging, section of the bell is known as the flexible margin, and it deforms slightly later in the swimming process than the rest of the bell. Until recently, however, Robojelly lacked this crucial piece of anatomy in its design.

Villanueva and his colleagues tested a number of different designs for their robot, some with and without an analog to a flexible margin. Initially, the artificial materials used in construction presented a problem. Unlike their natural counterparts, the artificial materials tended to fold as they deformed, reducing Robojelly's performance. After testing a number of designs and lengths for the folding margin, the engineers discovered that cutting slots into the bell reduced this unwanted folding effect.

This gave Robojelly a truer swimming stroke, as well as a big boost in speed.

"These results clearly demonstrate that the flap plays an important role in the propulsion mechanism of Robojelly and provides an anatomical understanding of natural jellyfish," said Villanuerva.

Text by American Physical Society Photo by Virginia Tech