The sudden decline in the snow crab population in the Bering Sea has triggered considerable concern among scientists, fisheries, and environmentalists alike. The collapse is alarming not only because of its immediate economic impact but also due to the broader implications for marine ecosystems. However, a critical examination of the prevailing explanations for this phenomenon reveals a troubling reliance on speculation rather than solid evidence. The central thesis of the NOAA Fisheries report—that warmer water temperatures increased snow crab metabolism, leading to their downfall—requires a more skeptical analysis. In this post, we’ll explore the weaknesses of this hypothesis, examine other plausible causes, and argue for a more comprehensive approach to understanding this ecological mystery.
The Metabolism Hypothesis: A Weak Foundation
However, scientists suspect that warmer water temperatures increased snow crab metabolism.
Unfortunately, available prey in the wild were insufficient to meet these new caloric demands. This effect may have been magnified by increasing crab density as the stock contracted to occupy shrinking cold-water habitat.
https://www.fisheries.noaa.gov/feature-story/snow-crab-collapse-due-ecological-shift-bering-sea
The core argument presented by NOAA Fisheries is that rising sea temperatures increased the metabolic rate of snow crabs, thereby boosting their caloric needs. According to the report, the available prey in the wild was insufficient to meet these new demands, leading to a population collapse. While this idea may seem intuitively plausible, it rests on a shaky foundation of assumptions rather than robust empirical data.
Firstly, the premise that warmer waters necessarily lead to significantly higher metabolic rates in snow crabs, resulting in increased food requirements, is not remotely substantiated. In general, it is true that ectothermic (cold-blooded) organisms experience higher metabolic rates in warmer environments. However, the report does not provide specific data on how much the metabolism of snow crabs actually increased under the conditions in the Bering Sea. Was this increase marginal or substantial? Without precise or even any measurements, this argument remains completely speculative. The relationship between temperature and metabolism is not linear, and various factors, such as the availability of food and the specific thermal tolerances of the species, can modulate this response.
Moreover, the report fails to account for the ecological adaptability of snow crabs. Like many marine species, snow crabs are known to exhibit behavioral and physiological adaptations to environmental changes. For instance, crabs may reduce their activity levels to conserve energy when food is scarce, or they may shift their feeding strategies to exploit different types of prey. The assumption that snow crabs would simply succumb to increased metabolic demands without any adaptive response seems overly simplistic. It overlooks the complex interactions between physiology, behavior, and environment that characterize the lives of these animals.
This logic is the classic version of the drunk looking under the lamppost for their lost keys because that’s the only area where he can see. In this case, Climate Change is the lamp.
“It’s really this combination of factors working together that caused the snow crab collapse,” said Litzow. “All of these factors are a result of climate change brought about by human activity since the start of the industrial revolution in the early 1900s. They indicate a wholesale transition towards boreal conditions in the southeast Bering Sea during these warm years.”
https://www.fisheries.noaa.gov/feature-story/snow-crab-collapse-due-ecological-shift-bering-sea
Ignoring Other Plausible Explanations
The metabolism hypothesis is not the only potential explanation for the snow crab decline, yet the report largely ignores other factors that could have played a significant role. This narrow focus is problematic, as it risks attributing the collapse to a single cause without fully exploring the broader ecological context.
One alternative explanation involves changes in predation pressure. The Bering Sea is home to various predators of snow crabs, including Pacific cod and other fish species. In recent years, populations of some of these predators have increased, potentially exerting more pressure on snow crab populations. Increased predation could reduce the number of adult crabs, leading to a decline in reproduction and, eventually, a population collapse. The report mentions nothing about changes in predator populations or their potential impact on snow crabs, leaving a significant gap in the analysis.
Another potential factor is overfishing. While the snow crab fishery is regulated, it is possible that past overfishing or illegal fishing activities have weakened the population, making it more vulnerable to environmental changes. Fisheries management often relies on stock assessments that can be imprecise, particularly in fluctuating environments like the Bering Sea. If the snow crab population was already under stress from overfishing, even a slight environmental change could have pushed it over the edge. Again, the report does not thoroughly investigate this possibility.
Additionally, environmental changes other than temperature could be influencing the snow crab population. For example, shifts in ocean currents, changes in the availability of specific prey species, or alterations in habitat conditions could all contribute to the observed decline. Marine ecosystems are inherently complex, with many interdependent factors, and isolating one variable as the primary cause of a population collapse is fraught with difficulties. The report’s failure to consider a broader range of environmental variables limits its explanatory power.
The Assumption of Limited Habitat
The report also posits that the snow crab population became more concentrated in shrinking cold-water habitats as the Bering Sea warmed, exacerbating the effects of increased metabolic demands. This idea hinges on the assumption that snow crabs are highly dependent on specific cold-water habitats and are unable or unwilling to migrate to other suitable areas. However, this assumption may not hold true.
Snow crabs are known to migrate seasonally and in response to environmental changes. They have been observed moving to deeper waters or different regions in search of more favorable conditions. If suitable habitats were available elsewhere in the Bering Sea, it is possible that at least some portion of the population could have relocated rather than remaining in a shrinking habitat and suffering the consequences. The report does not explore this possibility, nor does it provide data on the availability of alternative habitats or the actual movements of the snow crabs during the period of decline.
Furthermore, if snow crabs did not migrate, this could indicate other underlying stressors that are not related to temperature. Barriers to migration, such as physical obstacles, changes in habitat quality, or disruptions in migration cues, could have played a role. Alternatively, if the crabs were already weakened by other factors—such as disease or genetic issues—they might not have been able to respond to environmental changes as they normally would. These possibilities are not considered in the report, leaving us with an incomplete understanding of the situation.
The Problem with Singular Explanations
The reliance on a single explanation for the snow crab collapse—warmer waters leading to increased metabolism—reflects a broader problem in ecological and environmental studies. Complex phenomena are often oversimplified, with one factor being highlighted at the expense of others. This approach can lead to misguided conclusions and, ultimately, ineffective management strategies.
Marine ecosystems, like all ecological systems, are characterized by intricate interactions between multiple biotic and abiotic factors. Temperature is certainly an important variable, but it is not the only one, and its effects cannot be fully understood in isolation. By focusing primarily on temperature and metabolism, the NOAA report risks ignoring other critical drivers of population dynamics, such as predation, disease, fishing pressure, and habitat changes.
Moreover, attributing the snow crab collapse to a single cause may inadvertently lead to policy decisions that fail to address the true complexity of the problem. If management efforts are based on the assumption that reducing water temperatures (an unrealistic goal in the short term) or managing metabolic rates (an impossible task) are the keys to solving the problem, other vital issues may be neglected. For instance, addressing overfishing, improving predator management, or enhancing habitat conservation could be more effective strategies for ensuring the long-term sustainability of snow crab populations.
The Need for a More Comprehensive Approach
To fully understand the reasons behind the snow crab collapse, we need a more comprehensive and nuanced approach. This means moving beyond simplistic explanations and considering a wider range of factors that could be influencing the population. It also means collecting more robust data on the various potential causes, including temperature changes, predator-prey dynamics, fishing practices, and habitat conditions.
One possible avenue for future research could involve detailed studies on the metabolic rates of snow crabs under different environmental conditions. This would help clarify the extent to which temperature changes truly impact the crabs’ caloric needs and how these changes interact with other ecological factors. Additionally, tracking the movements and distribution of snow crabs in relation to temperature shifts could provide valuable insights into their adaptive behaviors and habitat preferences.
Another important step is to conduct thorough investigations into the role of predators and fishing pressure in the snow crab collapse. This could involve population modeling and historical analyses to determine whether increases in predator populations or changes in fishing practices correspond with the observed decline in snow crabs. Such studies would help to identify whether these factors are contributing to the problem and how they might be mitigated.
Finally, a more integrated approach to fisheries management is needed—one that considers the entire ecosystem rather than focusing on a single species or factor. This could involve implementing more precautionary fishing limits, enhancing habitat protection efforts, and developing adaptive management strategies that can respond to changing environmental conditions. By taking a broader view of the problem, we can develop more effective solutions that address the root causes of the snow crab collapse rather than just the symptoms.
Conclusion
The decline of the snow crab population in the Bering Sea is undoubtedly a serious issue, with significant ecological and economic implications. However, the current explanations for this collapse, as presented by NOAA Fisheries, are based on speculative assumptions and a narrow focus on temperature-induced metabolic changes. This approach overlooks other plausible causes and fails to capture the complexity of marine ecosystems.
To truly understand and address the snow crab collapse, we must adopt a more skeptical and comprehensive approach. This means questioning unproven assumptions, considering alternative explanations, and gathering more robust data on the various factors that could be influencing the population. By doing so, we can develop more effective management strategies that will help to ensure the long-term sustainability of snow crab populations and the health of the Bering Sea ecosystem as a whole.
In the end, the lesson here is one of caution: when faced with ecological mysteries, we must resist the temptation to jump to conclusions based on incomplete evidence. Instead, we should embrace the complexity of nature and strive to understand it in all its facets. Only then can we hope to develop solutions that are as nuanced and adaptive as the ecosystems we seek to protect.
The article Snow Crab Collapse Due to Ecological Shift in the Bering Sea from NOAA can be found here.
H/T Steve
Yeah. We have no real idea of what is going on with snow crabs, so of course it must be climate change?
2 deg C (maybe) in 100 years? I doubt the crabs even noticed it. I just do not buy it, but alarmism is very chic nowadays.
If it gets any hotter, the crabs will be precooked and ready for consumption.
What’s not to like?
I want to go where the oceans are boiling so I can get my snow crabs already cooked.
I want to go where the weather suits my clothes
And when their population recovers- the green blob won’t mention it and won’t want to hear about it. They’ll be too busy ranting about some other supposed climate caused problem.
Maybe the crabs were wiped out by virus or bacteria.
It will be like the frogs and the bees….climate change….oops, found a mite, bacteria or virus…which was obviously made worse by climate change….
Can crabs catch COVID?
Can they catch crabs from a toilet seat?
Alaska has volcanos.
I’m sure the list of disappearing things is longer than this, but here is a start: chocolate, peaches, coffee, tea, grapes, potatoes, avocados, maize, wheat, almonds, rice, soy, …, vanilla, and snow crabs. Next, crabs on humans. 😇
Then there is a different list that starts with birds, bats, and whales.
The coffee false alarm was told in essay Last Cup of Voffee in ebook Blowing Smoke.
Everybody should read Rud’s “Blowing Smoke.”
I just ordered it from the Amazon machine.
Due to some bat disease, here in Wokeachusetts and some nearby states, the feds forced a stoppage of logging work several years ago. It didn’t hurt the state forestry workers but it devastated the REAL WORLD of private foresters and loggers and landowners.
If the crabs are more energetic due to the warmer temperatures, then surely so is their food source. Does this mean that they have more to eat because of the higher activity of the prey?
The only way that I could see a collapse of the food chain due to higher activity would be IF the nutrient level which provides for the bottom of the chain being exhausted.
Did anyone measure the underlying nutrient levels? This would be an easy method to falsify or support the hypothesis. Do the test. Publish the result.
But, that would be science- it’s much easier and better for sales of your media, to just wildly speculate.
I always like to research the basics, here concerning snow crab metabolism. Two facts concerning Bering Sea snow crabs, both readily available at fisheries.noaa.gov.
Those two facts by themselves falsify the alarmist NOAA metabolism hypothesis for the present collapse of the snow crab population. Their climate alarm comprises legal gross negligence, since NOAA knew or should have known the basic facts from their own website.
And there is no cause for snow crab alarm, since the Bering fishery was sharply curtailed to preserve remaining mature adults, estimated in 2023 to be ‘only’ 1 billion (down sharply from ~8 billion in the 2018 survey). Snow crabs live about 20 years. Mature females spawn once a year, and each spawn comprises about 100,000 eggs. After hatching, Bering Sea females reach maturity between 5-8 years depending on bottom water temperature. So if higher water temperature had enabled the false metabolism hypothesis, the population would simply have eventually bounced back faster.
Final easily googled factoid. Snow crabs are found all around the Arctic, not just in the Bering Sea fishery. There is a significant North Atlantic fishery off Newfoundland and Labrador, whose population is (to now) apparently unaffected by Bering events.
As usual, scratch a ‘official’ climate alarm and find it simply isn’t so. Another good fishery example is PMEL and Oregon’s Netarts Bay Whiskey Creek oyster hatchery. Nothing to do with ocean acidification, everything to do with a mismanaged oyster hatchery. Story is one of two examples in essay Shell Games in ebook Blowing Smoke. The other example comprises clear cut academic misconduct by Fabricius.
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I am not sure that the author actually read the NOAA report. It clearly states that the
fisheries scientists found the following:
” a decline in sea ice, and an increase in:
”
Note that they explicitly say that disease in snow crabs increased and that the number
of predators increased.
While the author states that “The report mentions nothing about changes in predator populations or their potential impact on snow crabs, leaving a significant gap in the analysis.” Which is clearly wrong. Similarly the statement that the scientists didn’t
consider the role of disease is also wrong. Clearly the scientists found that there
were a considerable number of effects causing the snow crab decline.
Lastly the whole basis of the article appears to be misleading. The author is not
referring to the actual report and the evidence contained in it but rather to a press
release about the report. Clearly you would not expect a press release to contain all
the details that the author would like to see in a report and so you shouldn’t be surprised
if it just summarised the main results.
Isaac, yein. The biggest problem highlighted here is that the general public is usually only informed by the often misleading press reports of some new possible climate alarm study—which itself may or may not contain appropriate scientific nuances. Very recent examples include the Thwaites ‘doomsday’ glacier (yet again) and the demise of vanilla.
narry a single press report on the NOAA metabolism hypothesis mentioning increased predation or bitter crab disease as contribution factors. Just warmer water, itself a provable Fisheries.NOAA.gov falsehood.
And who writes the press releases?
When the press releases are junk, how often do knowledgeable government scientists challenge the press releases? Of course that would end their careers.
It often happens in state institutions that both accurate reports AND misleading articles appear. Like on the AIMS site about coral reefs. Then the alarmist article is highlighted and THAT makes the headlines. My guess is that it secures funding from all sides. The institution can defend by pointing to the reports and wash their hands off individuals who write misleading articles. Job done.
But it’s irresponsible for the institutions to “wash their hands off individuals who write misleading articles”.
A further comeback. I went back to the fisheries.noaa.gov site and read carefully what they themselves have now posted about their ‘study’ , They themselves said they ruled out increased Pacific cod predation. They themselves said they ruled out disease, since sampling had not shown a significant increase in diseased crabs from prior baseline. They themselves said the cause was almost certainly increased metabolism from warmer water, leading to mass starvation as crabs un-naturally concentrated in colder water pockets with less total available food.
Their own website loses your nuances in favor of perpetrating the general climate alarm, where elsewhere they simultaneously host the actual research data saying their metabolism/starvation alarm is wrong based on their own summer 2023 bottom water temperature survey data.
“…sampling had not shown a significant increase in diseased crabs from prior baseline.”
Sampling the survivors has some issues…
Maybe true, maybe not. Depends on how long the bitter crab disease takes to induce mortality. If very fast, you have a good point. If slow, then a prevalence sample is quite valid.
nailed it- the diseased crabs wouldn’t be available for sampling- not many anyway
diseased creatures in the wild don’t last long- who ever sees a sick wild animal? I never have and I’ve worked in forests for half a century
“almost certainly”
doesn’t look like science to me- but pure speculation- they ruled out some possible causes, then drew a conclusion without evidence
Human-induced borealization leads to the collapse of Bering Sea snow crab
This is the title from the official, scientific paper.
That sound rather alarmist to me.
The sea surface temperature anamoly maps for the North Pacific & Gulf of Alaska for the last couple of years are downright alarming because the anamolies are so hot. When you look at the maps it’s easy to imagine all the warming is due to geothermal inputs. The region is well established as seismically active. Little changes in ocean temperatures can have profound effects on the complex food chains. Everything is speculative when it comes to the ocean and fishery declines. The salmon populations in Alaska, Washington and British Columbia go up and down in productivity without any known explanation. Of course everytime they go down, they blame man, dams, pollution, etc. When they come back, sometimes with unheard of record runs. It’s a mystery. If salmon populations correlate to anything it’s ocean temperatures. The meteorologically important pacific decadal temperature occilation (PDO) was named by Steven R. Hare, who noticed it while studying salmon production pattern results in 1997.
Who knows about Snow Crab decline. But I would bet ocean temperatures have something to do with it. Rising ocean temperatures don’t necessarily have anything to do with changing atmospheric levels of carbon dioxide. Geothermal inputs are a more regional and reasonable explanation.
The NOAA fisheries report seems amateur, biased and agenda driven. All government reports should be graded and if they are found lacking the authors and their bosses should all get demerits filed against them. There should be certain minimum requirements for all government reports. In this case the question is, is the snow crab population declining in this area? They must show it clearly has and show how they know the crabs didn’t just move. If the population is found to be declining all possible causes must be listed. If one cause is singled out as the culprit it must be shown why the other possible causes were ruled out.
“if they are found lacking the authors and their bosses should all get
demeritsfired”fixed it! I want to hear Trump saying “you’re fired” to tens of thousands of burro-crats
Trump said “you’re fired” to all his illegal alien workers at his hotels and golf courses when he decided to go into politics.
I don’t have any experience with snow crabs or other marine critters up there, but I have a lot on fisheries. Although not good science it is not uncommon now to place such fluctuations due to something you don’t understand. In the last few decades this is helped and mixed with models where predictions are difficult to monitor. Martin Burkenroad worked in the Gulf of Mexico where I mostly did later and had a good reputation, publishing in 1951 what should be required reading. Quite a while ago I ran across his earlier paper where he was questioning what we have here because of the lack of understanding of natural fluctuations of which we still barely understand. Walters and Martell’s book seems very good and I was surprised to find Burkenroad’s paper referenced there about this problem.
Burkenroad, M. D. 1948. Fluctuation in abundance of Pacific halibut, In A Symposium on Fish Populations. Bulletin of the Bingham Oceanographic Collection. 11(4):81-129.
Walters, C. J. and S. J .D. Martell. 2004. Fisheries Ecology and Management. Princeton University Press.
Burkenroad, M. D. 1951. Some principles of marine fishery biology. Publications of the Institute of Marine Science of the University of Texas. 2(1):171-212.
What was interesting and very valuable was the discussion session of the symposium where Burkenroad questioned such assumptions and the lack of natural factors necessary to consider. With the paper they published discussions including Burkenroad’s six plus pages. Well known fisheries experts of the day were there, including Needler, Herrington, Ricker, and others. Burkenroad fielded numerous questions well and the symposium ended on this note. “Van Oosten: Before we adjourn, Dr. Huntsman, I want to thank you very much for calling this Symposium. I think it is one of finest I have every attended on fishery subjects….”
There was none of this “Human-induced borealization leads to the collapse of Bering Sea snow crab” and NOAA’s “At the height of the marine heatwave in the Bering Sea in 2018 and 2019, ocean temperatures in crab habitat remained below that critical 8°C threshold. However, scientists suspect that warmer water temperatures increased snow crab metabolism.” I just read a 2023 fisheries paper that avoided natural fluctuations.
How many Chinese crabbing boats been in the Bering Sea lately?? They’re everywhere else.
While NOAA acknowledged overfishing, they did not expose Russia’s huge illegal crab harvest. Granted, this report is from years ago. But, it exposes a legitimate problem especially since any statistics on Russian legal or illegal catches are both highly suspect.
https://c402277.ssl.cf1.rackcdn.com/publications/733/files/original/WWF_Illegal_crab_report_final_15_Oct_2014.pdf?1413407573
Excellent article. Much like the climate alarmists they go for the single factor sale. I also appreciate the mention of linearity. That’s what they always do. And they extrapolate further. That way you get to ‘massive species extinction’ and ‘millions of climate refugees due to environmental degredation’. I know several ( otherwise intelligent) people who are on that bandwagon. They are blind to the possible flaws and uncertainties in that mechanism. So, true believers. They get fed their daily dread and know no doubt, do not question.
That includs about 98% of the people of Wokeachusetts. I talk to lots of people and never hear anyone challenge The Big Lie about the climate. The media here sings the climate opera every day and virtually all politicians. The politicians who don’t believe The Lie are too timid to fight back. Cowards- because they love their easy job.
“we should embrace the complexity of nature and strive to understand it in all its facets. Only then can we hope to develop solutions that are as nuanced and adaptive as the ecosystems we seek to protect.” Can this not also be said of climate?
“In 2022, there was some good news for snow crab. During the Alaska Fisheries Science Center annual bottom trawl survey, scientists observed a return to cooler water temperatures more typical of historic times. These cooler conditions benefited snow crab. “
This collapse occurred in 2018-2019. They say their computer models work but the did not predict the warming or the cooling that they found in bottom temperatures.
They note that the crabs thrive in warmer temperatures in the lab. So, they just hypothesized that their increased metabolism and less prey were the problems. That is a speculative hypothesis worthy of study.
Let’s face it, those researchers are going to keep the flow of money coming. The paper is behind a pay wall so I cannot see who funded the study.