A map of radiation levels in Japan released by the US Department of Energy on Tuesday evening indicates that potentially dangerous levels of radioactive contamination have spread beyond the 13-mile evacuation zone surrounding the Fukushima Daiichi nuclear plant. The data is sure to further undermine confidence in Japan's response to the disaster. US authorities have recommended that Americans stay at least 50 miles from the Fukushima Daiichi plant. Here's the map, which was generated from the DOE's Aerial Monitoring System and ground sensors:

Spread of radiation for the Fukushima Daiichi nuclear plantSpread of radiation from the Fukushima Daiichi nuclear plant

To put these numbers in context, a typical chest X-ray produces 10 mRem. US EPA guidelines require government intervention if the public is exposed to more than 1000 mRem over four days. People near Fukushima could be exposed to that amount of radiation at least every 3.3 days in the red zone and anywhere from there to every 19 days in the orange zone above. Of course, it's unclear from the chart to what degree radiation levels in the area fluctuate over time. "Measurements show an area of greater radiation extending northwest from the accident," a DOE backgrounder notes, adding with dry understatement: "This area may be of interest to public safety officials and responders."

Tsunami flooding at Sendai Airport. Credit: Samuel Morse, courtesy USAF, via Wikimedia Commons.

Interesting clues from science, a few reflections, plus one refraction, in the wake of Japan's triple disasters: earthquake, tsunami, nuclear.

A letter in this week's Nature posits a fascinating hypothesis for why the enormous forces that build mountain ranges, trigger earthquakes, and create volcanoes, cause some areas of continental crust to buckle but not others. The culprit seems to be quartz:

Here we show that the abundance of crustal quartz, the weakest mineral in continental rocks, may strongly condition continental temperature and deformation. 

Furthermore, quartz-rich crust may also steer the process of plate tectonics: that shape-shifting of continents and oceans that continually, albeit slowly, rewrites the map of our world. If so, then quartz could be the weak trigger underlying the Japan Trench—epicenter of the 2011 Tōhoku (Sendai) Earthquake.

The work for this study was done with freely-available data from EarthScope—a program of the National Science Foundation that deploys thousands of seismic, GPS, and other geophysical instruments to examine the structure and evolution of North America.


EarthScope planning map.EarthScope planning map.


Science Insider reports that there are no drugs other for radiation poisoning other than potassium iodide, which only treats for the radioisotopes of iodine. But there are some in development:

A drug called Ex-RAD, developed by Onconova Therapeutics Inc., currently being tested as a prophylactic that could be given to first responders in a nuclear attack or to individuals preparing to enter a radioactive site. It's not the only drug though being tried out—CBLB502 has been shown to be effective in mice and monkeys.

Meanwhile, an interesting article in BBC Science puts Japan's nuclear emissions in a broader perspective, reminding us of the hazards of radiation we choose to accept:

A whole-body CT scan as part of a medical check-up... can deliver you a dose equivalent to being 1.5 miles from the centre of the Hiroshima explosion. Because more than 70 million CT scans are carried out each year, the US National Cancer Institute has estimated that 29,000 Americans will get cancer as a result of the CT scans they received in 2007 alone.

 CT scanner. Credit: US Navy via Wikimedia Commons.CT scanner. Credit: US Navy via Wikimedia Commons.


The Australian Broadcasting Company reports on collateral damage to internet service from Japan's megaquake:

Two [fiber-optic] cables linking Japan and the United States were damaged following the 9.0 magnitude earthquake, causing a 30 percent slowing of [internet] bandwidth. The damage may take a month to repair.

NASA's Earth Observatory posted an illuminating image of the damage to Japan's electrical grid, as seen from orbit (below).

The yellow areas indicate lights that were functioning in 2010 and 2011. Red shows power outages on March 12, 2011. Blue and green show clouds. Magenta shows lights obscured by clouds. The bright green points may indicate lights not observed in 2010 but visible in 2011. When you consider that Japan is roughly the size of California and 3.4 times more populous, that's adds up to a lot of people in the dark.

 Electricity Losses in Northeastern Japan following the Sendai quake. Yellow indicates lights functioning in 2010 and 2011. Red: power outages on March 12, 2011. Blue and green: clouds. Magenta: lights obscured by clouds. Bright green: may be lights not obElectricity Losses in Northeastern Japan following the Sendai quake Credit: NOAA National Geophysical Data Center.


Speaking of in the dark, Nature News published an interesting article by  Geoff Brumfiel called The Meltdown That Wasn't. (Not yet, at any rate, and hopefully never.) He describes just how treacherous the early hours and days at the Fukushima Daiichi Nuclear Power Plant must have been:

In the moments after the power was lost, the operators "would have literally been blind", says Margaret Harding, a nuclear engineer in Wilmington, North Carolina. Harding worked for two decades with General Electric, which designed Fukushima's boiling-water reactors, and she witnessed a similar outage in 1984 during a safety test at a boiling-water reactor in Switzerland. "Basically the emergency lights came on and all the panels went black," Harding says.

Brumfiel goes on to describe a guesstimated blow-by-blow of events and actions at reactor 1, including a variety of things done right:

At some point, the falling water levels must have left the fuel exposed... As temperatures rose above 1,000 °C, the steam in the pressure vessel began to oxidize the zirconium, probably releasing hydrogen gas. Meanwhile, fuel pellets, liberated from their shell, began to fall to the bottom of the reactor. The meltdown had begun... This was the crucial moment...  Slowly, the pile could build towards a 'critical mass' that would restart the nuclear process normally used to generate electricity... Nobody can be sure about this sequence of events because there has never been a full meltdown in a boiling-water reactor. Harding says that she thinks it's unlikely that the nuclear processes would have reignited. Even if they did, the worst case, in her opinion, is that the fuel would have burned through the steel pressure vessel and splattered onto the 'base mat', a thick concrete slab that would have spread out the fuel, extinguishing any fission reactions... But even that might have been catastrophic. The volatile hydrogen gas generated by the zirconium was safe inside the steel pressure vessel, but it was liable to explode if exposed to air in the outer containment vessel. If the blast were big enough, it might have breached the outer vessel's thick, concrete walls.

Finally, the dissenting views are washing up. Michael Hanlon, science editor of Britain's Daily Mail, writes that what's happened in Japan should be an ENDORSEMENT of nuclear power (his caps):

Think about it: despite being faced with a Magnitude 9 Great Earthquake which knocked the whole island of Honshu several feet to the west, a 35ft tsunami and the complete breakdown of the infrastructure, a handful of rather ancient atomic reactors have remained largely intact and have released only tiny amounts of radiation.

So easy to say from half a world away. Wonder if Hanlon would feel the same way if he was one of the Fukushima 50 trading his health, maybe his life, to try and keep it that way.


I came across a news story from the Singapore-based Strait Times on a public lecture that Yukiya Amano, the director general of the International Atomic Energy Agency (IAEA), gave last August that he probably wouldn't deliver today.

The headline, "Nuclear plants 'need not be far from urban areas,'" offers a good sense of the main point of his comments. Amano goes on to highlight Japan as a key reason we should have confidence in locating plants near urban areas:

He gave two examples of nuclear power plants built close to urban areas in Japan to stress his point. One is the Shimane plant, located just 10km from built-up areas in the town of Kashima-chou in the Matsue city in Shimane prefecture. The other, Tokai No. 2, sits 15km from populated areas in the town of Tokai.
Addressing concerns about safety, Mr Amano said that while it was not possible to eliminate all risks of accident, these could be contained in three ways to give ‘credible assurance of safety’.
First, he said, the design of reactors is much more advanced now and much safer, reducing the risk of an accident like the one in Chernobyl, Ukraine, where the world’s worst nuclear power plant accident killed 56 people in 1986 and caused thousands more cancer deaths.
The second measure related to having well-trained people run the plants, and the third, to having good construction work. 'It is like a house: even though the design is nice, if the construction work is sloppy, then the plant is not good,’ he said.

In Japan's ongoing nuclear crisis, Japanese officials have called for the evacuated of those living up to 12 miles from the site and urged people to remain indoors if they live up to 19 miles from the site. The evacuation has affected up to 200,000 people—a figure  that would have been vastly higher if the plant were closer to a major city.

Workers in Japan are still pouring seawater on overheating nuclear reactor rods at the Fukushima Daiichi Nuclear Power Station in an effort to decrease the risk of further meltdowns. (Read Mother Jones' detailed and regularly updated explainer on the current situation.) Here's what they're up against, as Kate Sheppard and Josh Harkinson explained shortly after the emergency began:

There are six boiling-water reactors on the site, though only three were in operation at the time of the earthquake. These systems, designed by General Electric, rely on an influx of water to cool the reactor core. But the water systems require electricity that was cut off by the earthquake. It also appears that something—the initial quake, the tsunami, or aftershocks—knocked the site's back-up generators offline. Without the cooling system bringing in water, the core of a reactor will start to overheat—which in turn heats up the water already in the system and causes more of it to turn to steam. Emergency responders have been forced to vent some of the steam, releasing radiation, in order to prevent the containment domes from exploding. They are in a race against the clock to bring in new water supplies before the reacting nuclear fuel heats up beyond control.

When I couldn't find a schematic that showed the Fukushima reactors' failed cooling systems in relation to their various other workings, I set out to remedy the problem in a visually accessible way. Think of the schematic diagram below like a New York City subway map. It shows the various components, connections, and relationships between the emergency water systems inside the Fukushima's five GE Mark I reactors. (A sixth reactor is a similar, though slightly newer, design.) It is based on the Nuclear Regulatory Commission's Boiling Water Reactor Systems Manual, which contains drawings of the various Mark I emergency systems. In places where the manual was unclear, I consulted Japanese news broadcasts. The drawings are not to scale and the layout of the pipes entirely my own (their location in relation to the various containment walls is based on the NRC manual).

Click here for an animated version of the diagram.

Mark I Reactor: Components of the Mark I ReactorMark I Reactor Components: (A) Uranium fuel rods; (B) Steam separator and dryer assemblies (C) Graphite control rods; (D) Vent and head spray; (E) Reactor vessel; (F) Feedwater inlet; (G) Low pressure coolant injection inlet; (H) Steam outlet; (I) Core spray inlet; (J) Jet pump; (K) Recirculation pump; (L) Concrete shell "drywell"; (M) Venting system; (N) Suppression pool; (O) Boron tank; (P) Condensate storage tank; (Q) High pressure coolant injection system; (R) HCIS turbine; (S) Automatic depressurization system; (T) Main turbine; (U) Connection to generator; (V) Condenser; (W) Circulating water; (X) Connection to outside service water; (Y) Concrete shield plug; (Z) Control rod drives. Illustrations by Joe Kloc.

Mark I Reactor Running Normally: TKTKTKTKMark I Reactor Running Normally: Recirculation loops (RED) keep pressurized water circulating through the uranium core of the reactor. When water is heated by the uranium core it turns to steam. It passes through the steam separator and dryer assemblies positioned above the core (ORANGE) and then moves through the steam pipe. The steam is used to turn a turbine connected (PURPLE) to an electrical generator. It is then turned back into liquid by a condenser and cooled by a pipe (GREY) of circulating cold water. The water is then pumped back into the reactor, where the process begins again.

Last Friday, New York Gov. Andrew Cuomo announced that he wants to see the Indian Point nuclear power plant, located 38 miles from New York City, shut down. "This plant in this proximity to the city was never a good risk," he explained. Cuomo was hardly the first person to express concerns about the plant, which supplies power to New York City and its suburbs. A day before the governor's statement, the nearly four-decade-old site was one of 14 US nuclear plants cited for safety "near-misses" in a report by the Union of Concerned Scientists. Which raises the question: What should New Yorkers do if a Japan-like emergency were to hit Indian Point?

Recently that question got a lot more complicated. The Nuclear Regulatory Commission (NRC) currently sets the evacuation zone around American nuclear power plants, also known as the "Plume Exposure Pathway Emergency Planning Zone," at 10 miles. Japanese authorities have evacuated residents living within about 19 miles of the damaged Fukushima Daiichi Nuclear Power Plant. But US officials have urged all Americans within 50 miles of the troubled Japanese reactors to get out of the way. Does this contradictory advice mean that our 10-mile emergency plans need to be revisited?

NRC Chairman Gregory Jaczko, in an appearance on CSPAN on Sunday, defended the 10-mile zones, noting that sites in the US don't have as many reactors as the Japanese plant and that the plans are meant only for the immediate response. "What we want to do is build a system that we know at 10 miles we can activate that system quickly and we can mobilize it quickly," said Jaczko. "We always appreciate that there may be circumstances where we have to expand that if necessary."

But the US government's advice to keep 50 miles away from Fukushima has "opened up a Pandora's box," says Edwin Lyman, a senior scientist with the Union of Concerned Scientists who focuses on nuclear power and security. The group has previously argued that the zones need to be reevaluated. "This is certainly going to raise questions about the safety of those who live more than 10 miles from the plants in the US."

Widening the evacuation zones to 50 miles around the United States' 104 plants would affect a number of densely populated areas. The Indian Point zone would, of course, then include all of New York City—meaning that the 21 million people in the 50-mile radius might need to relocate in case of a serious emergency. Maryland's Calvert Cliffs Nuclear Power Plant is nearly 50 miles from Washington, DC, home to 500,000. The McGuire Nuclear Station is just 17 miles from Charlotte, North Carolina, which has 730,000 residents. (See our chart below to see how many cities and towns are located within the 50-mile zone, or check out CNN's map that lets you see how close you live to a nuclear power plant.)

I grew up a little less than 20 miles from the New Jersey's Salem Nuclear Power Plant and Hope Creek Nuclear Generating Station, which have three reactor units between them. (The Hope Creek generator is a GE Mark 1 boiling water reactor, the same model as those that are currently in distress in Japan.) The plant is also about 50 miles from Philadelphia, with a population of 1.4 million. Philadelphia also has the Limerick Nuclear Power Plant just 21 miles northwest of the city.

I lived outside the 10-mile evacuation zone for the New Jersey power plant, but my friends on the other side of the line had siren systems in their neighborhoods, did regular evacuation drills, and received updated information every year explaining the emergency evacuation plans. There were also plans in place to distribute potassium iodide to those in the zone in the event of an emergency. The Baptist Bible summer camp I attended was inside the zone, which meant that every year all of us campers had to practice an evacuation drill. The emergency siren would go off and we would all line up at the flagpole. Then we'd board a big yellow school bus and drive away, ostensibly to safety somewhere outside the evacuation zone. Even as a child, I was a little confused about the whole thing: If something really bad happened, where would we go, and how would we even know that a bus would actually come pick us up, anyway? Moreover, what were the people right on the other side of that 10-mile radius supposed to do?

Setting 50 miles as the new standard evacuation zone "would be an enormous challenge," says the UCS's Lyman. Not only would officials have to devise a plan to move hundreds of thousands of additional people, they'd also have to educate many more residents and local emergency responders who probably aren't even aware that they live relatively close to a nuclear power plant. It would also complicate things for the nuclear industry. The Nuclear Energy Institute, the industry's lobbying group here in the US, pushed back on noting that the 50-mile zone was necessary in Japan, stating last week that it had "questions about the scientific basis" for issuing that advisory. A look at the locations of nuclear power plants across the country makes it clear that changing the zone would present significant logistical questions, to say the least:

Last week, I wrote about an unusual piece of legislation in Texas that would ban workplace discrimination against creationists. HB 2454 would make it a crime to "discriminate against or penalize in any manner" a professor or student based on his or her "conduct of research relating to the theory of intelligent design." On Friday, the author of the bill, Republican state Rep. Bill Zedler of Arlington, called me to defend it. Here's an excerpt from our conversation:

Mother Jones: Are you a creationist?

Bill Zedler: Evolutionists will go "Oh, it just happened by chance." Today we know that’s false. Today we know that even a single-celled organism is hugely complex. When was the last time we’ve seen someone go into a windstorm or a tornado or any other kind of natural disaster, and say "Guess what? That windstorm just created a watch."

MJ: Are you saying a windstorm is like the Big Bang?

BZ: It has to do with things occurring by chance.

MJ: Ok. [Long pause]. Is a windstorm analogous to a genetic mutation?

BZ: Well, not really. I don’t want to go that far. Let me put it to you this way: When we talk about people with faith, there is no greater faith than that life began by chance, with the amount of knowledge that we know now.

MJ: I thought people doing work on the science of evolution typically don’t weigh in on what caused the beginning of life.

BZ: I wonder why?

MJ: They say they don’t know the answer.

BZ: If somebody does decide to weigh in, why should they be discriminated against?

MJ: Because they don’t have the scientific evidence to substantiate their views.

BZ: The debate ought to be: “How did it happen?” But we’re not gonna allow that one to be brought up! I don’t think they oughta be thrown off campus if they come up with it.

MJ: The bill basically deals with the treatment of creationists as a matter of workplace discrimination. It got me thinking about other efforts to deal with that issue, such as legislation that prohibits workplace discrimination based on gender identity, sexual orientation, or marital status. A lot of states have laws outlawing that type of discrimination, but Texas doesn’t. Do you think that it should?

Seismically speaking, it's been a rough few months on the Pacific rim. On February 27, 2010, an 8.8-magnitude earthquake struck Chile. In September, two major quakes rocked New Zealand's South Island, and a 6.3 followed in February in Christchurch. Just a few weeks after that, the devastating 9.0 quake struck Japan, causing a tsunami and a nuclear crisis. These quakes occurred on three of the four "corners" of the notoriously jumpy Ring of Fire. The other corner? The West Coast of the United States. So does this series of earthquakes up the US's chances of the dreaded "Big One"?

This Newsweek story from last week suggests that the answer is yes, since the earth is "like a great brass bell, which when struck by an enormous hammer blow on one side sets to vibrating and ringing from all over." Rogue seismologist Jim Berkland, who claims to be able to predict earthquakes based in part on tides and the moon, has also warned that a major US quake is imminent.

GE's ESBWR reactor (passive cooling system is #17)GE's ESBWR reactor (passive cooling system is #17)

EDITOR'S NOTE: On Monday, this story was updated with responses from GE.

The nuclear industry likes to claim that each new reactor model is safer than the last. The unfolding nuclear emergency in Japan suggests otherwise.

A major source of the problems at the Fukushima Daiichi nuclear plant is its inability to cool down its overheating reactors without electricity, which was knocked out by the earthquake and tsunami. Missing from most of Fukushima's reactors is a passive cooling system that operates without electricity. Phased out by General Electric just as Fukushima was being constructed in the early 1970s, the old system could have operated even after the earthquake and tsunami wiped out the plant's electrical supply and diesel generators. "It can go on essentially forever" without electricity, says Mujid Kazimi, a professor of nuclear engineering at MIT. If it had been in use at Fukushima, he adds, it could have significantly slowed down the plant's overheating problems.

General Electric developed passive cooling systems for use in its boiling water reactors, which were first introduced in the 1950s. Its last passively cooled reactor, the BWR3, debuted in the late 1960s. The BWR3's backup cooling system runs entirely on gravity and steam generated by the reactor. As the steam rises inside the reactor vessel, it is captured by an isolation condenser, cooled off, and pumped back towards the hot core by a gravity-driven injection system. "Something that can circulate on its own would be very helpful" at Fukushima, Kazimi says.

But passive cooling is no guarantee against disaster. The steam in the reactor will boil off after six to eight hours if more water isn't added, which might have been what happened before the plant's Unit 1 reactor, its only BWR3, caught fire on Saturday. It's also possible that Unit 1 was compromised by the earthquake or tsunami. A spokesman for GE, Michael Tetuan, said that GE doesn't yet have enough information to compare how its different reactor models fared in the disaster.

GE has dealt with Japan's nuclear crisis in part by trying to distance its older technologies from its newer ones. "BWR technology has evolved; each design more simple than the previous," says a fact sheet on the company's nuclear crisis website. "As a result, each generation of BWR has provided increased safety and improved economics."

Yet GE's shift away from passive cooling technologies during the 1970s illustrates how some "improvements" come with trade-offs. Tetuan says that GE abandoned the passive cooling system not because it didn't work, but because the new system could keep water over the fuel rods even in the event of a partial pipe break—a perceived safety benefit. Kazimi also speculated that it may have been harder to seal off the old system inside a containment dome. But the airtight domes at Fukushima have proven to be of limited value; Japanese plant operators have been forced to vent them to release radioactive steam building up inside.

Tellingly, GE has revived its passive cooling technology in its next-generation prototype reactor, the Economic Simplified Boiling Water Reactor. Tetuan says that GE first began researching a new passive cooling system in the wake of the Three Mile Island disaster, when utilities requested reactors that were simpler to operate, had fewer components, and didn't depend on diesel generators for backup. A fact sheet on the ESBWR brags that its "passive design features, such as passive containment cooling, reduce the number of active systems, increasing safety." GE claims that ESBWR is so safe, in fact, that humans would be better off spending their time worrying about threats from outer space. The company figures that a large asteroid is 11 times more likely to strike Earth in the next 100 years than the ESBWR is to fail.

Of course, as Japan shows, improbable disasters actually happen, and when they do, they can take out some pretty fancy nuclear plants.

TEPCO: Japan's BP?

What do you think, does TEPCO merit the BP badge of dishonor, the Black Wave Award (okay, I just made that up): Where corporate greed, in a head-on with scientific and engineering reality, ignites environmental catastrophe?

Reports here and here and here suggest the problems with Japan's nuclear power industry are entrenched and systemic. TEPCO, like BP, may simply be the weak link that broke first.

Japan was offered a preview of what was coming this week with the 2007 Chūetsu Offshore Earthquake, a 6.8 temblor that caused serious and "unforeseen" problems at TEPCO's Kashiwazaki-Kariwa Nuclear Power Plant, about 150 miles from the Fukushima plant, on Japan's west coast:

[S]cientists used data from the magnitude 6.8 earthquake to conclude that the builders of the Kashiwazaki-Kariwa plant, the world's largest by electrical output, may have unknowingly constructed it directly on top of an active seismic fault. "Not finding the fault was a miss on our part," said Toshiaki Sakai, who heads the engineering group in charge of Tokyo Electric's nuclear plants. "But it was not a fatal miss by any means."

There has been a misconception since the early days of nuclear power that human error or mechanical failure, in other words risk factors within the plant itself, are the most significant variables regarding possible radiological release to the environment. In fact, the greatest threat to a plant´s operation may lie outside its walls [i.e., earthquakes]... A distinct new emphasis on external hazards in nuclear safety consideration followed the earthquake that hit [TEPCO's] Kashiwazaki-Kariwa Nuclear Power Plant in July 2007, the largest to ever affect a nuclear facility.

  • From New Scientist today on the troubles that arose in the wake of the 2007 quake, plus TEPCO's reluctant reporting of them:

Three reactors at the world's largest nuclear plant, Kashiwazaki-Kariwa, shut down after a 6.8-magnitude earthquake. A fire briefly [broke] out in one of the units. Tepco initially [said] that the quake caused no radiation leaks, but days later [admitted] that 1200 litres of radioactive water had washed into the sea and several drums containing nuclear waste lost their lids after falling over. In the wake of the incident, experts debate whether Japan's nuclear plants are engineered to standards high enough to cope with major quakes—the country's Nuclear Safety Commission stipulates that all new plants must be built to withstand only a magnitude-6.5 event.

The current disaster, still unfolding, raises questions I discussed in earlier posts, including the fact that geologists didn't think the fault offshore capable of a 9.0 quake.

But also:

  • Why didn't TEPCO build for a large tsunami?
  • Why weren't electrical cooling pumps raised above floodwaters?
  • Why were back-up batteries only good for eight hours and why weren't they raised above floodwaters?

And why did the hydrogen explosions happen at all? The Union of Concerned Scientists suggests that design flaws may have led to these explosions—possibly the same flaws unearthed during structural integrity tests on a reactor in North Carolina back in the 1970s.

To paraphrase my words in the BP Cover-Up: The nuclear power industry has been gambling for too long, under great pressure, at the border of controllable engineering, without the extreme safety equipment and protocols needed to stave off disaster.

Migrating With Mom

This post courtesy BBC Earth. For more wildlife news, find BBC Earth on Facebook and Posterous.

Any great journey starts out with a little trepidation, think back to your first day of school, walking out into the big wide world (or playground) and then looking back to see your guardian eagerly watching and willing you to keep going. These first steps are always the hardest, and as one of the the largest mammals on the earth there's no exception.

Scientifically classified as one of the 'big-winged' (Megaptera) species, Humpback whales make their annual move north from the warm Hawaiian Island waters from March onwards. Seeking fresh food and cooler temperatures, these magnificent giants will travel through currents so challenging that only perseverance will see them through. And as a newborn, the first ocean crossing will be something to remember.

After approximately four months of not eating and living off her own blubber, it's not just the cow's instinct which is telling her that it's time to move on. With calf in tow, she sets off. From the low-latitude breeding grounds, they will travel at 3 to 9 mph or as fast as the calf can swim. Sometimes this can take up to three months, but at 1,000 miles per month, at this stage they can’t afford to waste a moment of their time. Purposefully, the pair follow the migratory path to the Alaskan waters where a great feast awaits. While the calf drinks up to 132 gallons of its mother's rich milk every day, the waxing and waning moon only reminds the mother of the importance of this move. As the sea floor falls far deeper below them both, and tropical sandy shores are replaced with glaciers, the time has almost come!

With one final push, the tired pair finally arrive. And welcoming them are numerous other North Pacific Humpbacks, who have made the same trip and are already making the most of the plentiful supply of fish. All the hard work isn't over yet. There's breaching to practice, strengthening of fins and tail but most importantly, the skills of the hunt to master! The first mission is however behind them, and with cow and calf still together and gaining strength with each passing day, the memory of their journey will be with them for the rest of their lives—which can be anything up to 50 years. Check out the extraordinary fishing techniques used by watching the BBC Earth filming first below. Sea for yourself what makes them magnificent!