The 2015 Arctic Report Card: NOAA Failed Walrus Science!

Guest essay by Jim Steele

Director emeritus Sierra Nevada Field Campus, San Francisco State University

Good scientists fully understand that complex issues with high uncertainties require two or more working hypotheses. NOAA failed to communicate the great uncertainties and alternative. Instead NOAA’s report card made claims that hinge on the unproven hypothesis that a reduction in sea ice is detrimental by denying walruses access to foraging habitat. In the Pacific the number of calves per cow increased as has calf survival, both indicators of a growing population, contradicting NOAA’s claim,. As detailed in Hijacking Successful Walrus Conservation, historical records for the Pacific walrus (Fay 1982, 1989) observed an overall increase in the use of land haulouts coinciding with increasing populations of recovering walrus. In the Barents Sea’s Svalbard archipelago, despite the greatest decline of sea ice, recent research has also observed an increased use of land haulouts coinciding with an exponential population growth, a 48% increase in abundance between 2006 and 20012 (Kovacs 2014). Yet despite all the positive indicators, NOAA downplays growing populations and makes the empty assertion, “the overall carrying capacity of the region for walruses is almost certainly declining because of sea ice declines.”

The full weight of evidence suggests an alternative hypothesis is more likely. Less sea ice allows more access to larger areas of bountiful foraging habitat that had been previously covered by heavy ice. The carrying capacity of walrus habitat – its ability to nourish and sustain a population – will only decline if the following are true but perusal of the evidence suggests the carrying capacity has increased.

  1. Carrying capacity will decline if the population becomes so abundant it reduces the prey base and
  2. competition for dwindling food creates nutritional stress
  3. Carrying capacity will decline if there is a general decline in marine productivity
  4. Carrying capacity will decline if the areal extent of potential foraging habitat is reduced, and/or
  5. Carrying capacity will decline if access to foraging habitat is reduced.

 

1. Food Competition, Density-dependent Regulation, and Healthy Vital Rates

 

Populations are naturally regulated by “density-dependent” factors. As a growing population adds more individuals to a given area, the density increases. As the density approaches the carrying capacity of that habitat, competition for a limited food supply increases nutritional stress. Marine mammals such as polar bears, ringed seals and walruses respond to nutritional stress by reducing their reproductive output, which ultimately reduces population growth. The ratio of calves to cows decreases because pregnancy rates decline, young cows defer their first year of pregnancy to an older age, and calf survival rates decrease. Conversely when the food supply is abundant, walruses’ pregnancy rates increase, cows give birth at an earlier age, and calf survival rates increase. When those critical factors raise the ratio of calves to cows the population increases.

Based on 20th century surveys, researchers believed the Pacific walrus had rebounded from an overhunted population reduced to ~ 50,000 in the 1950s which then grew to ~250,000 to 300,000 walrus by 1980 (Fay 1989). Consistent with density-dependent theory, when the population was below the carrying capacity in the 1950s and 60s, researchers observed the highest ratios of calves per cows. As the population grew subsistence hunters reported increasing numbers of leaner individuals and a steady decline in the ratio of calves to females suggesting walruses were reaching or exceeding the region’s carrying capacity. The resulting decline in reproductive output caused the population growth rate to stop and the population peaked around 1980. Researchers then calculated a brief population decline during 1980s exacerbated by an uptick in Russian walrus harvests (Fay 1997). But the calves:cows ratio then began to increase throughout the 1990s and some researchers believed population growth had resumed. The calves:cows ratio is now as high as it was in the 1960s when the recovering population was rapidly growing (McCracken 2014). Presently calf survival rates have nearly doubled (Taylor 2015) and cow’s age of first pregnancy has been increasingly younger (Garlich-Miller 2006). All those vital signs usually suggest a well fed, growing population, supporting early research but contradicting NOAA’s current argument that the carrying capacity is “certainly declining”.

2. Marine Productivity is Improving

The shallow shelves of the Bering and Chukchi seas prevent nutrients from sinking to a dark abyss far from the reach of photosynthesizing plankton. Shallow seas more readily upwell nutrients enabling high rates of productivity. Furthermore ocean currents bathe large sections of those shallow shelves with nutrient rich subtropical waters further enhancing productivity. And because surface productivity more rapidly reaches the floor of those shallow shelves, bottom dwelling organisms collectively called the “benthos,” receive over 70% of the energy sequestered at the surface. As a result the Bering and Chukchi seas sustain some of the earth’s richest bounty of bottom dwelling prey sought by walrus, gray whales and bearded seals (Sirenko 2007). Contrary to earlier suggestions that global warming may possibly decrease productivity (Grebmeier 2006), satellite observations have determined marine productivity has increased by 30% since the 1990s (Arrigo 2015). The reason for this increase is elementary. Less sea ice allows more photosynthesis. Grebmeier 2015 has now reported that the Bering and Chukchi Sea “hotspots” she has studied have sustained high levels of biomass over the past 4 decades.

From a marine productivity perspective, the evidence does not support NOAA’s claim of a declining carrying capacity; just the opposite. Increased productivity has increased the carrying capacity.

3. Areal Extent of Foraging Habitat Has Increased

 

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The key variable that determines walrus foraging habitat is depth. Telemetry studies found walrus spent nearly 98% of their time foraging in shallow water no deeper than 60 meters (Jay 2005) and other observations suggest foraging at depths deeper than 80 meters is unlikely. As seen in Figure 1, much of the Arctic is not suitable for walruses. The darkest blue regions represent inaccessible regions of great depth. The 3 lightest shades of blue-gray outline the only depths with potential walrus foraging habitat.

The white mass in the upper right of Figure 1 represents the summer minimum of the 2007 ice pack. The average historic summer minimum (the yellow line in Fig.1) indicates large portions of the Chukchi Sea’s foraging habitat have been covered with summer ice concentrations of 50% and greater for much of the 20th century. Because walrus avoid ice-covered waters where sea ice concentration is 80% or greater, any heavy ice concentrations reduce the areal extent of walrus foraging habitat.

Notice that along the northern coast of Alaska in the Beaufort Sea, sea ice historically retreated over deep waters every year. Thus the most recent retreat of sea ice further northward did not impact the areal extent of foraging habitat in that region. Likewise once the Chukchi summer sea ice retreated over the deep Arctic Ocean, any additional retreat had little consequence. In contrast, the initial reduction in summer sea ice over the western Chukchi Sea opened vast regions of potential foraging habitat.

It is believed that 70 to 80% of the total Pacific walrus population exploits the western Chukchi habitat especially during the autumn when reduced sea ice exposes the most habitat. Russian researchers surveying the western Chukchi in September of 1980, estimated approximately 150,000 walrus had hauled out in roughly equal numbers on sea ice and on land. A repeat of that survey in October as freezing conditions increased, revealed the number of walrus hauled out on ice had been greatly reduced but walrus on land remained unchanged (Fedoseev 1981). Clearly 75,000 walrus were not forced onto the Russian coast due to the lack of ice. Although the lack of sea ice in 2007 very likely increased the numbers of walrus hauling out on land, media hyperbole that sensationalized terrestrial haulouts are solely due to global warming, inexcusably ignores all historical observations of natural land haulouts. Based on observations that roughly 50% of the walruses use land haulouts despite plentiful potential resting platforms of sea ice, any occupation of land haulouts serves as an indicator of where walrus accessed Chukchi habitat as sea ice cover waxed and waned.

In Figure 3 below (from Garlich-Miller 2011) the numbers locate known land haulouts. The red arrow I added points to Cape Serdse-Kamen (#50) that has always been occupied in September and October during past surveys. The numbers to the west of Cape Serdse-Kamen and to the north around Wrangel Island represent traditional haulouts that are used only in years of light sea ice but unoccupied in years of heavy ice (Fay 1984). For example despite the shallow foraging habitat north of Wrangel Island, walruses were not observed there in the 1980s (Fedoseev 1981). When sub-freezing winds removed much of the thick Arctic ice from this region in the 1990s when Arctic Oscillation shifted, walrus rapidly exploited the region’s resources and over 120,000 walruses hauled around Wrangel Island. Such observations support the hypothesis that reduced ice increases available foraging habitat and consequently the western Arctic’s carrying capacity.

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Due to heavy sea ice cover, access to rich foraging habitat on shallow shelves naturally fluctuates between seasons, years, decades and millennia. The heavy ice of the last Ice Age must have been the nadir for walrus populations. Not only was there maximum sea ice coverage, but also the drop in sea level left the shallow shelves of the Arctic Seas high and dry. Although this allowed humans to enter North America, it relegated walrus populations to narrower shelf waters as far south as central California. Eventually Holocene warmth raised sea level and reduced sea ice allowing walrus populations to once again flourish in the Arctic. Flexible migratory patterns are likely an adaptation to the constant changes in sea ice even during the warm Holocene. Proxy data covering the past 9000 years from Point Barrow revealed annual sea ice covering the eastern Chukchi Sea varied from only 5.5 to 9 months, and summer sea surface temperatures ranged from 3 to 7.5 °C, much higher than today (McKay 2008).

Seasonally winter ice forces walrus to abandon the Chukchi. They re-enter after the warmth of spring reduces sea ice cover. Whether caused by CO2-driven global warming, observed natural changes in atmospheric circulation due to the Arctic Oscillation, or changes in the volume of intruding waters associated with the Pacific Decadal Oscillation, the extent of summer sea ice summer has fluctuated greatly over decades as seen in Figure 5 (from Jay 2012.)

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4. Accessing Foraging Habitat

NOAA began their report card by arguing, “Sea ice deterioration due to global climate change is thought to be the most pervasive threat to ice-associated marine mammals in the Arctic, including walruses.” But that threat has yet to be substantiated. The perceived threat to walruses is solely based on a hypothesis that walruses “require” sea ice as a platform from which they dive to suction clams, worms, etc. from the ocean floor. Based on that belief, some researchers argue that declining sea ice denies access to habitat and forces them to forage closer to their land haulouts. Expanding on that assumption NOAA argues Arctic’s carrying capacity “must be in decline.”

But several lines of evidence clearly demonstrate walruses do not “require” sea ice as a resting platform in order to hunt. A resting platform of sea ice is likely an opportunistic and beneficial convenience – not a requirement. For example after breeding a large proportion of male walruses abandon the sea ice and migrate south to dwell in land haul outs in ice free waters along the Russian and Alaskan coast (represented by red dots in Figure 3). From those traditional land haulouts they embark on foraging trips that last for 4 to 10 days and range as much as 130 kilometers away (Jay 2005). In addition satellite radiotelemetry determined walruses throughout the Bering and Chukchi spend over 80% of their time swimming, and the amount of time in the water was the same whether walrus used sea ice or land for a resting platform. Swimming at a relaxed speed of 10 km/hour, a walrus easily range over 200 km while foraging along the way (Jay 2010, Udevitz 2009).

Some researchers suggest that the lack of resting platforms of sea-ice will restrict walrus to hunting only along the coast and hypothesizing they will more quickly deplete more limited accessible resources. However the opposite scenario is more likely. Heavy sea ice restricts hunting grounds and the most extreme example would occur if heavy ice remained all summer in the Chukchi forcing herds to remain in the Bering Sea throughout the year. Certainly the Bering Sea’s prey base would be rapidly depleted. The migratory behavior of females and their calves into the shallow waters of the Chukchi each summer is most likely a behavior that evolved to reduce resource competition and exploit temporary access to rich foraging habitat. With a greater reduction of Chukchi summer ice, migrating herds can spread out and reduce localized foraging pressure.

NOAA Expert Opinion Claims Pacific Walrus have declined by 50%. Seriously?

Finally NOAA’s report card suggested that “expert opinion” calculated a 50% decline in Pacific Walrus populations between 1980 and 2000. The experts did agree the population had decreased during the early 1980s due to density-dependent effects when population abundance increased and exceeded the region’s carrying capacity. But the expert consensus ended there. Fay 1986 suggested after a relatively brief decline in the 80s, population growth subsequently resumed. A growing population would be in agreement with recent observations of increased marine productivity, greater access to habitat due to decreased heavy ice, higher calves:cows ratios and higher survival rates.

Estimating walrus abundance is extremely difficult and all experts agree that abundance estimates have extremely wide error bars and are totally unreliable. Russian and American biologists jointly surveyed walrus populations in the autumn every 5 years between 1975 and 1990, but survey efforts were suspended because experts could not agree on how to interpret limited data and the tremendous resulting uncertainty (Speckman 2010). The major problem revolves around estimating how many walrus are in the water and escape detection. Furthermore due walrus movements, it was impossible to replicate survey transects and constrain error estimates. A repeated transect just one week later often resulted in observed numbers differing by 2 or 3 orders of magnitude.

To circumvent survey uncertainties there have been attempts to model abundance based on observed age structure of the population (Taylor 2015), and those model results disagree with earlier calculations of a growing population. They suggested populations continued to decline from 1980 to 2000, but admit their results after 2003 were equivocal. They also acknowledged that information provided by age structure data cannot mitigate uncertainties in the population size, admitting the absolute size of the Pacific walrus population will “continue to be speculative until accurate empirical estimation of the population size becomes feasible

Thus experts would likely agree that NOAA’s claim of a 50% reduction due to “expert opinion” is likewise speculative and rather meaningless. NOAA failed to express that extreme uncertainty and failed to report the tremendous wide range in abundance estimates. For example in the most recent survey (Speckman 2010) of wintering walrus in the Bering Sea, researchers used heat detectors calibrated by high-resolution photographic evidence to estimate abundance. Unfortunately swimming walruses were undetectable. For the region surveyed, they estimated 129,000 walrus that would support a estimated 50% decline. However their 95% confidence ranged from 55,000 to 507,000 walrus. Furthermore due to time and weather constraints, the survey covered less than 50% of the Bering Sea habitat known to contain walrus. A complete survey may well have increased the estimate to well over 200,000 individuals. A midrange estimate would be similar to peak estimates of the 1980s, and high-end estimates would support hypotheses of a growing population in the Pacific; a growth that parallels observed growth in the Atlantic walrus.

Curiouser and curiouser, NOAA cited McCracken 2014 who used Speckman’s knowingly biased underestimate of 129,000 to suggest the increasing ratio of calves per cow supported a declining walrus population. Biologically such an assertion contradicts density-dependent mechanisms. Increased reproduction increases a population, unless survival rates drastically declined, but rates had increased.

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McCracken 2014 argued that calves:cows ratios are inversely correlated with population abundance as illustrated in Figure 4. However that correlation is partly speculative and unsupported and depends on using Speckman’s unrealistic estimate of half the population. No one disagrees that overhunting reduced the population in the 1950s so that more food became available for the survivors stimulating walruses to increase reproductive output as evidenced by high calves:cows ratios; a high ratio that approached the theoretical maximum. Density increased as walruses recovered from overhunting (and increasing sea ice was coincidentally recovering from its minimal in the late 1930s) so that the carrying capacity declined and walrus responded with declining calves:cows ratios that bottomed out in the 1980s. But the consensus on any population trends stops in the 1980s.

McCracken 2014 acknowledged that the validity of their inverse correlation is totally dependent upon the assumption that 300,000 walrus was the maximum population that could be sustained by the region. However they did not explore the possibility that the carrying capacity could possibly increase due to less sea ice and higher marine productivity. So they assumed that any observations of higher calves:cows ratios that would normally indicate a growing population, were only possible if the population had declined by such an extent that more food again became available.

The only dynamic that could have possibly offset increased ocean productivity and cause a population decline in an era of regulated hunting, and conservation efforts that are now protecting haulouts, was a strictly hypothetical dynamic that less sea ice prevents access to foraging habitat and was reducing the Arctic’s carrying capacity. But all reported evidence discussed above contradicts that hypothesis and McCracken’s suggestion the population had declined by 50% is untenable.

NOAAs claim that the “carrying capacity is almost certainly declining because of sea ice declines” is advocated by USGS and US Fish and Wildlife researchers who believe that CO2 warming and declining sea ice must be bad. That belief is advocated in the opening paragraphs of nearly every publication. Wedded to that belief their interpretations ignore robust evidence suggesting less has been beneficial. So one must wonder how politicized those agencies have become and if political pressure has biased their publications. Researchers in those agencies likewise ignored their own observations that it was cycles of thick springtime ice in the Beaufort Sea that caused declines in ringed seals and polar bear body condition. Instead without evidence, they only advocated that reduced summer ice, consistent with CO2 warming, has negatively impacted polar bear populations and walrus Such unsupported biased interpretations are most likely the result of the politicization of science, and I fear this decade will be viewed as the darkest days of environmental science.

Jim Steele is author of Landscapes & Cycles: An Environmentalist’s Journey to Climate Skepticism

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72 thoughts on “The 2015 Arctic Report Card: NOAA Failed Walrus Science!

  1. “Walrus Science”?
    Does that come from Walrus wisdom:
    “The time has come,” the Walrus said,
    “To talk of many things:
    Of shoes–and ships–and sealing-wax–
    Of cabbages–and kings–
    And why the sea is boiling hot–
    And whether pigs have wings.”

  2. This is another case of something we were sure of was wrong. Very unsettled science. It is time to remove climate science from the sciences and call it what it is – CSWAG.

  3. another wonderful piece
    I find this staggering – “95% confidence ranged from 55,000 to 507,000 walrus”
    there can be no confidence in that at all

    • No Bubba, I’m wondering how bad their estimating if their guess could be 5% outside this range.
      If I guess how much you have in your front pocket, I would be more confident to say between $.55 and $5,000 , than $23.48 to $31.71. But that is Probability and Statistic Mathematics and we all know how good they are at that.

      • Global Warming has even affected mathematics. “Less than” has become “greater than” so that cooling temperatures actually are warming temperatures. There is no need to add or subtract fudge factors to show upward increasing trends. Likewise, 507,000 is now less than 55,000. Why do we even bother using math and logic anymore?

    • Back in high school, when I was about as left and greenie as you can get (which is really the only time when its almost acceptable, i.e., you’re immature and stupid), I took the “right-wing”, i.e., rational side in a debate about how badly things were then (this was the 80s). We had been force-fed books like “The Fate of the Earth” and “Entropy”, etc. David Suzuki was the patron saint of most of my teachers.
      It was actually fairly easy to win the debate: I asked how many species were actually at risk, and got a number from a debating opponent. I merely had to open a book and got a totally different number, then another to get another totally different number, etc, repeat.
      “Seems the numbers are a bit….elastic. Are you sure you know what you’re talking about?”
      I got a D, but dined out on high school kewl points with the non-lefty kids for months. And thus began my (too) long drift from the loony left to the rational “right”.

    • Business owners have been jailed for being less exact.
      I wonder if you went to the taxman at tax-time and say “I’m 95% confident my income was somewhere between $55,000 and $507,000”, if your income was actually closer to $507,000, of course.
      The other way, they’d pretty much take the higher amount, wouldn’t they?

  4. “The full weight of evidence suggests an alternative hypothesis is more likely. Less sea ice allows more access to larger areas of bountiful foraging habitat that had been previously covered by heavy ice.”
    In other words, there is a hypothesis that “warmer is good”. Who could have possibly guessed?

  5. “carrying capacity is almost certainly declining because of sea ice declines”
    Yet as I recall the walrus is a benthic feeder. How much ice is there on the sea floor>?

  6. And why is NOAA spending our tax dollars in an attempt to explain the biosphere to us when they can’t even get their own job done?
    Bernie

  7. Thanks, Dr. Steele. Common sense in scientific research should always be required.
    It seems like NOAA is trying to scare us into believing that man-emitted CO2 is the culprit for all of the bad things that happen naturally, and if they are not actually happening, then make them up to order.

  8. Thanks for another great article Jim. Between you and Dr Crockford over at polarbearscience.com I’ve learned so much about these things.

  9. Well done, Jim. The fact that these NOAA authors cannot document the population decline they say exists yet still chose to write this ‘scary’ story is appalling. The portion of the report on population is as full of ‘likely’ as IPCC reports, yet they are talking about the status now and in the recent past, not the future.
    Here is my walrus video from 2013 – nothing has changed since then.

    Oddly, well after the annual haulout event this fall gathered media attention, US Fish & Wildlife estimated the herd size was as large as it was last year. http://polarbearscience.com/2015/09/13/pacific-walrus-herd-hauled-out-in-alaska-during-august-was-as-large-as-last-years/
    It is my impression that except for journalists, even fewer people buy the walrus hype than embrace the polar bear hype, no matter how many scary stories they write.
    Dr. Susan Crockford, Zoologist

    • NOAA:
      Uses satellites to measure and track sea ice.
      Uses sonar to measure depth and ocean depth structures.
      Uses Microwaves to measure temperature and surface structures, including plant density.
      And NOAA claims they wander around the arctic trying to count large shape shifting walrus blobs?
      If a fishfinder (depth sounder) can be used to track individual large species of fish and underwater critters…
      If thermal tracking units (cameras) can be used by wildlife officials and even civilians to identify and track nocturnal animals.
      Why in blazes is it so hard for the alleged department of rocket scientists to find a better method of accurately tracking Walrus, seal and whale populations?
      Rocket science isn’t what it used to be!
      Gavin deserves his magic wand, fairy dust, dress and butterfly wings!

  10. Gosh – it appears that walruses may be able to go for a swim and a meal from a beach, as well as from an ice shelf! Also, greater range of habitat could mean increased food access which could lead to population growth!
    Who’d have thunk it?
    Must have taken billions in grant money to come up with alternative theories (like CAGW).

  11. {bold emphasis mine – John Whitman}
    Jim Steele concluded (in his article ‘The 2015 Arctic Report Card: NOAA Failed Walrus Science!’),
    “NOAAs claim that the “carrying capacity is almost certainly declining because of sea ice declines” is advocated by USGS and US Fish and Wildlife researchers who believe that CO2 warming and declining sea ice must be bad. That belief is advocated in the opening paragraphs of nearly every publication. Wedded to that belief their interpretations ignore robust evidence suggesting less has been beneficial. So one must wonder how politicized those agencies have become and if political pressure has biased their publications. Researchers in those agencies likewise ignored their own observations that it was cycles of thick springtime ice in the Beaufort Sea that caused declines in ringed seals and polar bear body condition. Instead without evidence, they only advocated that reduced summer ice, consistent with CO2 warming, has negatively impacted polar bear populations and walrus Such unsupported biased interpretations are most likely the result of the politicization of science, and I fear this decade will be viewed as the darkest days of environmental science.”

    Unless NOAA is held strictly accountable by multiple and redundant outside/ independent objective science-correction-mechanisms, then the darkest days are yet to be seen for any science related to climate; such as science focused on the environment.
    To NOAA: Think about what you have done. Think about it as the American culture turns away from you and moves to better independent objective focuses on climate science.
    John

    • “To NOAA: Think about what you have done. Think about it as the American culture turns away from you and moves to better independent objective focuses on climate science.”
      NOAA’s self destruction of its own credibility is appalling. There needs to be a major shakeout in their ranks. No mercy or excuses, just pink slips all the way down.

    • eyesonu on December 24, 2015 at 1:22 am
      NOAA’s self destruction of its own credibility is appalling. There needs to be a major shakeout in their ranks. No mercy or excuses, just pink slips all the way down.

      eyesonu,
      Pink slips? No. I am in a benevolent mood. So I recommend the NOAA leadership who aided in and approved creation of preudo-climate studies and datasets (etc) should be given jobs tracking down the paranormal claims and supernatural myths like bigfoot, Elvis, alien abductions, miracles, and such like. Prima fascia, they seem to have some considerable talent for something like that.
      John

  12. I can’t express how thankful I am that there are still people doing truthful scientific inquiry. NOAA is not properly serving The People with their cocked up alarmist information. I think it’s time to “shock the pool and restock”.

  13. The poly bear gambit failed, so they’re trying walruses. Hey, good enough for government “science”!

  14. “the overall carrying capacity of the region for walruses is almost certainly declining because of sea ice declines.”?
    Evidently someone at NOAA believes that the diet of walruses includes sea ice.

    • Perhaps they just believe that the walrus food needs to be refrigerated or it will spoil! Doh!!! the stupid is strong with NOAA!
      Merry Christmas!
      Joe

  15. God bless you, Jim Steele. Yours is a voice of reason in a field where hyperbole and insanity are seemingly rewarded, these days.
    As a former Christian, but still a celebrant of Christmas, aware of the fact that biology, evolution and natural selection resemble an arms race, and that as a practical matter, what’s good for humans often works against the interests of other species, I’d like to, nevertheless, and quite non-ironically, wish all readers of WattsUpWithThat a very Merry Christmas and a happy and prosperous New Year. May you find meaning in your lives, an appreciation for the privileged place that all humans enjoy in Earth’s evolutionary tree, and may you be respectful of, and grateful for the lives of any animal food you feast upon. To paraphrase author Edward Abbey, who once made a similar wish to the javelinas of the Colorado plateau, Merry Christmas, walruses.

  16. It seems odd that air breathing mammals such as walrus, seals and whales would benefit from increased ice. Unless the ice melts, the animals would eventually exhaust their energy supplies to keep breathing holes open, resulting in death. It seems highly unlikely that any mammal could survive year after year, trapped under the ice.
    The biggest question that I have looking at the walrus is “why are they brown not white?”. If the walrus was truly a creature adapted to ice, it would be white like the polar bear so that it could hide on the ice to minimize predation. The brown color of the walrus best matches the color of earth, not ice, so it seems most likely that the walrus is actually adapted to land not ice, and simply makes use of the ice out of convenience, not necessity.

  17. Walruses are intelligent and resourceful animals. Fortunately, their behavior is not dictated by climate “scientists.”

  18. The key variable that determines walrus foraging habitat is depth. Telemetry studies found walrus spent nearly 98% of their time foraging in shallow water no deeper than 60 meters (Jay 2005) and other observations suggest foraging at depths deeper than 80 meters is unlikely.

    I was curious about this and skimmed the study looking for details. It was based on 57 transmitter-tagged walruses (57 working out of 59 tagged), but only 8 had the Satellite-linked time-depth recorders (SLTDR). the rest only reported location when out of water:

    Transmitter configurations varied considerably; however,
    all transmitters had a conductivity sensor that disabled transmissions when the device was underwater to conserve battery life.

    (the transmitters were all attached with a stainless steel band to one tusk, so I assume a conductivity sensor would only permit transmission when completely out of water).
    Unless there is some reason the preferred forage is sparser at depths below 60 meters, I would think that walrus would go to whatever depth is required to feed. We know other marine mammals routinely go much deeper than 60 meters.
    Here is what the study said regarding the depth information:

    The satellite-linked time-depth
    recorders (SLTDRs), which were deployed on walruses at
    Cape Peirce in late June to mid-August of 1995 and 1996,
    reported the accumulated time spent in 15 m depth classes
    over periods of one hour (3 SLTDRs) and six hours (5
    SLTDRs). Walruses regularly haul out to rest between
    periods of offshore foraging on the seafloor. A study of
    walrus dive behavior within the current study area indi-
    cated that maximum dive depth was bimodal, with very
    few dives between 10 and 20 m depth. The deeper dives
    were primarily foraging dives (> 94% of all deep diving
    time) (Jay et al., 2001). Therefore, in the current study,
    each one-hour and six-hour period was assigned to a
    behavior category: foraging if the animal spent at least
    one-third of the period at a depth of 15 m or more, or non-
    foraging otherwise. Subsequently, each period was linked
    to locations that were acquired within three hours of the
    mid-point of the period.

    I did not find a breakdown of time spent at depth, but if I read the above process correctly the data was assigned to one and six-hour buckets (depending on SLTDR type) based on whether the animal spent one third of that time deeper than 15m. Note also the location associated with the reported depth are those “acquired within three hours of the mid-point of the period”. Per prior observation, those would be haul-out locations, not the actual diving position.
    I infer that 5 of the 8 SLTDRs had lower-resolution data (6 hour intervals) and only three reported data for 1 hour intervals. By contrast, my dive computer, which is far from top of the line, records depth and temperature in intervals as small as 15 seconds. I understand of course why gear which must operate unattended for a year or more must make some compromises, but the result is much lower resolution data.
    With a six-hour time bucket, a walrus would have to spend two hours at depth greater than 60m in order to be counted as foraging at greater than 15m under this methodology. It would be really interesting to see the time-depth profile difference between the 1-hour and 6-hour SLTDRs.
    So my question with all that background is: just how much confidence do we have that “walrus spend 98% of their time foraging in water no deeper than 60m”?

    • typo:

      With a six-hour time bucket, a walrus would have to spend two hours at depth greater than 60m in order to be counted as foraging at greater than 15m60m under this methodology

      original in strike through, corrected in bold.

    • Alan, there is high confidence that walrus rarely forage below 80 meters. The specifics of the study you highlight are just one more example of observations indicating the limits of walrus foraging. Other observations are based on telemetry that pinpoints foraging locations and overlays the known bathymetry of that location. I don’t think any walrus expert would challenge the statement that walrus foraging is limited by depth.
      Your comment that “We know other marine mammals routinely go much deeper than 60 meters” is not very meaningful. Sure Sperm whales dive to great depths in search of big squids, but what does that tell us about walruses.
      You suggested that “walrus would go to whatever depth is required to feed” but in addition to changes in the benthos with depth, walrus anatomy and physiology is the most likely reason the depth at which they forage is limited. Their thick layer of body fat needed for thermoregulation, creates buoyancy which requires increasingly more energy to overcome the deeper they dive. Diving marine mammals have various mechanisms to sustain oxygen deficits, prevent the “bends” and prevent water from entering their lungs. I do not know the details of their anatomical and physiological adaptations, but I do know that the evolution of such adaptations differs for various species and limits the depths at which they forage.

      • Thanks for the reply. It just seemed that 60m was a shallow limit for a marine animal and the details I found in the linked Jay 2005 study did not appear to support such a high confidence. I’ve since done some additional reading and find that walrus are uniformly reported to be shallow divers and limited to about 30 minutes under water, which supports your contention about limited foraging habitat.
        Enjoyed the article by the way.

      • Alan Watt, I applaud your critical thinking and willingness to go the extra mile and check out the research claims whether they support or disagree with your beliefs. That’s what good skeptics do.

      • Wouldn’t the fat compress under pressure, therefor add nothing extra to buoyancy? Whales also have a thick layer of fat and dive to km depths.

      • Greg it is not an issue that their buoyancy prevents deep diving , but the amount of energy required to deeper depths relative to the food they will find. Deeper dives tai more energy and longer periods of oxygen deprivation but with diminishing rewards. Shallower shelves typically contain 10 times the prey biomass as deeper regions.

      • To answer my question above, “google” tells me that a walrus can hold its breath for 30 minutes.
        A sea covered in ice would be a barren wasteland.

  19. All Arctic and desert animals go through ‘boom/bust’ population cycles. Any ‘marginal climate’ critters have this feature. A slight increase in rain/snow or deficit of the same leads to huge changes in population levels. I grew up in the Sonora and Mohave deserts and witnessed this cycle at work repeatedly.

  20. Terrific post. Learned a lot. That NOAA could ‘officially’ make such egregiously wrong statements about the simple walrus facts leads me to a stronger conviction that Lamar Smith’s NOAA whistleblowers on the Karl pause buster paper must know about a smoking gun.

  21. A repeat of that survey in October as freezing conditions increased, revealed the number of walrus hauled out on ice had been greatly reduced but walrus on land remained unchanged
    ================
    it appears that walrus would rather lie on a relatively warm beach than a cold block of ice. it appears the walrus knows more about survival in cold conditions than your average NOAA scientists. but then again, the walrus doesn’t have to kiss some politicians ass to keep its job. 97% of all taxpayers agree, NOAA scientists are less trustworthy than used car salesmen.

  22. Excellent common-sense points. And thanks Dr. Crockford for a continuing voice of correction and scientific sanity.

  23. Hmmm…More text and graphic carpet bombing 🙁
    Does anyone actually bother reading and digesting all this stuff?

    • Village Idiot, Why are you here if you don’t appreciate good science? I understand some folks prefer quick hits without all the supporting evidence, but my scientific training requires a thorough accounting of the facts.A good portion of the readers here do indeed appreciate that style. If you desire a quick debunking that you can trust, may I suggest Steve Goddard’s excellent site that clearly and concisely presents why history contradicts all recent catastrophic climate claims hyped in the media and by alarmists. Go to https://stevengoddard.wordpress.com

  24. It appears that this study is a lame attempt at replacing the poley bear (which has shown to be in rude health, as a species) with the walrus as the ‘man-made global warming’ alarmists’ mascot du jour.
    Unfortunately for The Hockey Team, it appears that this attempt has fallen at the first hurdle: They have tried to replace one discredited alarmist ‘call-to-arms’ with another, thereby making themselves look even more stupid.

    • Dreadnought:
      To me the issue is more that getting an accurate count of very mobile animals in hostile environments is subject to a great deal of uncertainty. The honest thing to do in those circumstances is make estimates based on as many independent methodologies as you have available and establish the most reasonable range for population. Ignoring the uncertainty range and reporting just one value is dishonest.

  25. Jim Steele,
    Thank you for an excellent essay/presentation.
    A mammal the must breathe air can’t live under the ice. An exception would be a seal with an open blowhole. But a froze over blowhole or a polar bear would be bad news for the seal.
    Have there been any documented occurrences of ice blocking walrus migration/escape to ice free waters further south? An arctic storm pushing sea ice into the Bearing Straight would seem to be a possible catastrophic event for walrus that would be trapped from their southern migration..

    • The Atlantic Walrus is not currently very migratory, likely due to southern populations being eliminated by LIA overhunting. The surviving groups now stay all winter in polynyas. At those locations there are observations of them being caught in a freeze and blocked from entering the water, and thus becoming easy picking for polar bears.
      I suspect the whole subspecies of non-migratory “Laptev walrus” evolved by being trapped when the Arctic entered a cooling trend. Genetics show this subspecies is closely related to migratory Pacific Walrus and very recently were separated an no longer interbreed with the Pacific Walrus in the Bering. During the warm Holocene an ice free migratory path from the Bering Sea to the Chukchi Sea extended all the way to the Laptev. As the Arctic cooled the last 5000 years that pathway became choked with ice around the New Siberian Islands (the islands in the upper left corner of Figure 1 above). Stuck in the Laptev they became non-migratory surviving the winters in the extensive polynya. And there too are accounts of Walrus being frozen out, wandering over the ice with severely frost bitten flippers or eaten.

  26. Thanks Jim, your normal very high standard of work. If only all environmentalists thought as you do.

  27. “reduction in sea ice is detrimental by denying walruses access to foraging habitat”
    howzxat?
    Walrus feed in the water, ice or land only provides birthing area and perhaps different rest than floating in the water using their inflatable bladder, and when sunny lower heat loss than floating in the water.
    Sounds like yet another incompetent assumption by eco-activists who don’t do homework.

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