Fish Ear Stones: The Latest Climate Change Proxy

Guest essay by Eric Worrall

According to Professor Karin Limburg, studying the composition of bony growths in fish ears can reveal historical ocean hypoxia and other environmental issues.

How is climate change affecting fishes? There are clues inside their ears

May 14, 2019 8.44pm AEST
Karin Limburg

Climate change affects all life on Earth, but it poses unique challenges for aquatic species. For example, as water warms it holds less dissolved oxygen than cooler water. As a result, the world’s oceans, coastal seas, estuaries, rivers and lakes are undergoing a process known as “deoxygenation.” 

When dissolved oxygen levels fall to about 2 milligrams per liter – compared to a normal range of roughly 5 to 10 mg/L – many aquatic organisms become severely stressed. Scientists call this low oxygen threshold “hypoxia.” 

Globally fisheries generate US$362 billion annually. Scientists are already forecasting loss of fish biomass due to warming water. But can we measure effects on fish directly? 

For some climate change impacts, the answer is yes. Increasingly, a window on the secret lives of fishes is opening up through study of tiny, calcified formations inside fish skulls called otoliths – literally, “ear-stones.”

Read more:

The description of otoliths is interesting – but why preface it with vague and in my opinion likely misleading warnings about impending climate damage to global fisheries?

If oceans do warm, a very gradual process, in most cases fish distressed by the warmer water will simply migrate North a few miles, until they find cooler water more to their liking. Hinting that gradual ocean warming presents a major threat to global fisheries is pure alarmism.

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Bill P.
May 14, 2019 6:34 pm

The resort to alarmism is the very reason public sentiment in favor of the orthodox climate change policies has waned.

Had they simply stuck to facts rather than doctrinaire truisms that were not allowed ever to be questioned – not to mention asking ten percent of humans to foot the entire bill for all such policies – the conversation would be a lot less fraught.

Alan Tomalty
Reply to  Bill P.
May 14, 2019 7:42 pm

Had they simply stuck to facts, there would be no conversation now. It would have become a non issue. The climate scientists would have had to enter other fields and dream up other ways to scare us to keep the funding alive.

Gerry, England
Reply to  Alan Tomalty
May 15, 2019 5:35 am

Spurred on by governments with a desire to ‘do something’.

Reply to  Gerry, England
May 15, 2019 6:32 am

Global warming is making fish go deaf. We MUST act now.

Reply to  Alan Tomalty
May 15, 2019 6:28 am

Facts, we don’t need no stinking facts.

Scientists call this low oxygen threshold “hypoxia.”

No, hypoxia is NOT a threshold, it is the low oxygen state.

Caligula Jones
Reply to  Bill P.
May 15, 2019 7:41 am

I guess because everyone laughed at the “bee tongues as proxy”, they thought “might as well go all in” on nonsense:

May 14, 2019 6:45 pm

In this part of the world we’re seeing winter species much later into the season than in the past. I’m not sure we need to worry about warming.

Charles Higley
Reply to  Cube
May 14, 2019 8:43 pm

The report is a crock, of fish. They ignore the fact that these species have evolved in waters much warmer than now and, oh, by the way, with more CO2 and warmer water, photosynthetic processes increase and there is more oxygen in the water. They assume only that the oxygen will outgas and ignore all the positive aspects of the natural world. Seeing the world through AGW glasses, they are. Stupid they are.

Reply to  Charles Higley
May 14, 2019 11:13 pm

“Stupid, they are?”

The purpose of being a “scientist” is to publish, be recognised by your peers, and therefore increase your salary. Any science that gets done is purely an accidental happy byproduct of this process.

In the current system, research into Bolivian nose weevils would never get funding, because it would never get published. However, research into the effects of climate change on Bolivian nose weevils will get tons of funding and headlining in Nature.

I always like to think of the quote: “Science advances one death at a time”. Perhaps one could offer some assistance?

Reply to  Charles Higley
May 15, 2019 6:02 am

The report is a crock…..

Of course it is…..they didn’t measure fish in the wild….they artificially induced the condition…and measured that

It’s assumptions all the way down…

Joel O’Bryan
May 14, 2019 7:04 pm

Because … Climate Change.
Send grant money.

Rentseeking behavior: Just another reason the climate change scam must be ignored

May 14, 2019 7:05 pm

Nothing more than a hypothesis without scientific accreditation. Like CC in general.

David Chappell
May 14, 2019 7:06 pm

Earrings! Wait till Mann hears about them.

“And amazingly, young fish deposit tiny increments on a daily basis.” Presumably older fish do as well rather than, as implied, once a year.,

May 14, 2019 7:12 pm

CAWG fanatics resort to alarmism! In other news, Water Wet!

I’ve been reading hyperbolic articles about CO2 reaching 415ppm, the highest level in 3 million years. Heck, even Fox News is jumping on that bandwagon… not to surprising I guess, they’ve been moving left for a while now.

May 14, 2019 7:55 pm

Fish are relatively unimportant. The really important things are algae. link

Algae allow us and almost every other organism you can think of, living or dead, to be here.

If you’re worried about the oxygen in the ocean, you should be studying algae. The ocean isn’t going to warm enough to make much difference in oxygen levels.

R.S. Brown
May 14, 2019 7:58 pm
May 14, 2019 8:58 pm

I first read the Headline as :”Fish Ear Stones: The Latest Climate Change Proxy”… it makes just as much sense.

J Mac
May 14, 2019 9:29 pm

Back in 1978/79, I sometimes caught ‘sheepshead’ fish (fresh water drum) in the Fox River channel crossing Lake Butte des Morts, on the north end of Oshkosh WI. Cleaning them, I discovered they have ‘stones’ in their heads up to an inch in diameter. Today I learned these ‘stones’ are called otoliths that help the fish remain vertically oriented in turbid, low visibility waters.


bit chilly
Reply to  J Mac
May 14, 2019 11:37 pm

J Mac, apparently if you cut them in half and clean the cut face up on a polishing table it will reveal rings the fish can be aged by. The easier way is to look at a scale from the same fish under a microscope (with the added bonus the fish does not have to be killed ) but that wouldn’t look so “sciency” .

Reply to  bit chilly
May 15, 2019 3:42 am

Otoliths are preferred because they fossilize much better than scales.

Dave Miller
Reply to  J Mac
May 15, 2019 8:37 am

Same experience, a few years before, on the Niagara River in Buffalo, NY.

I live today on a tributary of Lake Buttes des Morts. 😉

May 14, 2019 10:48 pm

I guess these guys never heard of tropical fish. I keep my tanks at about 76F-78F. My fish would be stressed at lower temperatures.


Moderately Cross of East Anglia
May 15, 2019 12:43 am

Oh dear…fish are going to go the same way as coffee beans! Oh wait…

Lee Collins
May 15, 2019 1:22 am

We have otoliths too. About 3 years ago I started to feel very sick and my balance totally went. Couldn’t walk in a straight line. Diagnosed as BPPV (vertigo) where the otoliths dislodge and free float around the ear canals, bashing into sensitive hair like receptors and sending strong signals to the vestibular system which are incompatible with those being sent by the eyes and other physical sensors. Doc applied the Epley manoeuvre and suggested a daily head exercise routine to relocate the wandering otoliths. Said I should be fine in a couple of months . . three years later . . still feel lousy. Any magic cures/suggestions gratefully accepted.

Caligula Jones
Reply to  Lee Collins
May 15, 2019 7:38 am

Try medical pot. Might not actually help with the dizziness, but at least you’ll have an excuse.

Seriously, I perform the Epley and it works for me, so I’m sorry you’re still having issues. Hope things work out.

Flight Level
May 15, 2019 1:55 am

Cristal Ball: The ever new climate science universal proxy. Now with WIFI interface and automated alarmism publications writing software.

May 15, 2019 2:43 am

What about when the waters at the north pole start boiling? What then? Where will the fish go north then?(sarc)

May 15, 2019 3:35 am

hmm seeing as the Japanese used “studying the otoliths” in whales ears as justification for ongoing whaliing
maybe they could show the otoliths they collected and count the rings and show….
probably sweet fa

May 15, 2019 3:40 am

Start drawing your target bulls eye first you score a direct hit every time when do we stop paying for these phony studies?

May 15, 2019 3:48 am

The oceans are very well oxygenated and has been for the last 35 million years, because the deep ocean water is salt, well oxygenated water that sinks as it is cooled. Hypoxia/anoxia is only possible in local semi-isolated basins like the Black Sea or the Baltic.

And it will stay that way until Antarctica moves away from the pole, or is reconnected to another continent.

Tom in Florida
May 15, 2019 4:38 am

“When dissolved oxygen levels fall to about 2 milligrams per liter – compared to a normal range of roughly 5 to 10 mg/L ”

The question is what causes such a decline and how likely is it to happen. I read the article and didn’t see any answer.

Reply to  Tom in Florida
May 15, 2019 9:20 am

Using actual solubility tables, I found in sea water at 25C and 1 bar, the solubility of O2 decreases by approx. 0.1 PPM with a 2C temperature rise. That change is fairly steady as you increase temperature. Did these people ever look at data instead of making sweeping generalizations?

May 15, 2019 5:42 am

The original piece entirely ignores any actual NUMBERS — at what temperatures does this affect fish ears?

also mixes up the myriad reasons for supposed “dead zones” and “low oxygen zones”. Most have nothing to do with climate change or alleged “warming seas”.

Caligula Jones
Reply to  Kip Hansen
May 15, 2019 7:52 am

“The original piece entirely ignores any actual NUMBERS — at what temperatures does this affect fish ears?”

Well, duh. This is New Science.

First, you have a theory, then you create some evidence, then your prove your theory because you have some evidence.

You then issue a press release and media outlets will get their 20-something Senior Science Editor to (barely) re-write it with a Very Scary clickbait headline. This “article” will then be shared on social media to get hits and forwarded by people who turn their lights off for one hour each year…

Rinse. Repeat.

HD Hoese
May 15, 2019 7:22 am OPEN ACCESS

From the abstract
“Baltic cod otoliths, always somewhat difficult to age (Hüssy, 2010), became increasingly unreadable through the 2000s (Hüssy et al., 2016). In 2014, the stock assessment failed, due in great part to large uncertainties and inconsistencies in age determination…..We conclude that cod otolith chemistry proxies not only inform about the hypoxia, growth, and metabolic status of cod, retrospectively throughout life, but also reflect the worsening situation for cod in the Baltic.”

From the paper
“We also develop a heuristic model as a dynamic hypothesis, that manganese uptake (and hence, the proxies) is a function of both exogenous (biogeochemical) and endogenous (physiological) controls.” “Figure 2. Hypothesized mechanism of otolith manganese incorporation.” “Lifetime data, averaged over the entire otolith transects, did not reveal as many insights, and generally produced noisy relationships.”

From the discussion
“Analysis of annual data, parsed on laser transects along the dorsal axis of Baltic cod otoliths, demonstrated complex, individualistic patterns of life histories. Despite the fact that the Baltic Sea is a very large system, and our collections constituted but a small sampling, some striking patterns emerged that reflect the changing circumstances of cod confronting hypoxia.”

They then go on with a discussion of other elements like Iodine and Strontium and end up with
“Careful study and testing will be required, but benefits as demonstrated here, in terms of understanding hypoxia exposure, will be substantial.”

In the discussion they cite these papers about Louisiana which I have not read yet, but the titles are, shall we say, interesting. Mohan, J., and Walther, B. (2016). Out of breath and hungry: natural tags reveal trophic resilience of Atlantic croaker to hypoxia exposure. Mar. Ecol. Prog. Ser. 560, 207–221. doi: 10.3354/meps11934 and Altenritter, M. E., Cohuo, A., and Walther, B. D. (2018). Proportions of demersal fish exposed to sublethal hypoxia revealed by otolith chemistry. Mar. Ecol. Prog. Ser. 589, 193–208. doi: 10.3354/meps12469

I was recently sent this–
“Nearly 9000 square-miles of ocean along the Gulf Coast is uninhabitable by marine life”

And responded–
That is simply not true. I have studied a lot of coasts for decades including 30 years in Louisiana, and the only dead zone I ever saw was the Houston Ship Channel in the late 1950s. This is a quote from a paper recently out about it. DO is dissolved oxygen, a characteristic of the misnamed “DEAD ZONE. ” “Currently, it is not clear whether the effects of low bottom DO on the spatial dynamics of the shrimp fleet are a net cost or a net benefit to the fishery.” I heard this more or less back in the 1970s after the big floods of 73-75. Shrimpers have to be smart to survive and this is not their worst problem. The following paper is most interesting to me because I saw it once. Studies of these “zones” have mostly avoided stomach analyses.

Craig, J. K., P. C.Gillikin, M. A. Magelnicki , and L. N. May. 2010. Habitat use of cownose rays (Rhinoptera bonasus) in a highly productive, hypoxic continental shelf ecosystem. Fisheries Oceanography. 19(4):301-317.

The biggest problem with otolith ageing is verification. It has worked. This may be a useful method, but they clutter it. They should have to write it out in pencil.

Steve O
May 15, 2019 7:34 am

“The description of otoliths is interesting – but why preface it with vague and in my opinion likely misleading warnings about impending climate damage to global fisheries.”

That’s the way the presentation of science works. You do your work and present your findings. At the end, you offer the required hat-tip to the dominant narrative.

May 15, 2019 10:53 am

“For example, as water warms it holds less dissolved oxygen than cooler water. As a result, the world’s oceans, coastal seas, estuaries, rivers and lakes are undergoing a process known as “deoxygenation.”

How odd, extreme alarmist hype as an introduction that has virtually nothing to do with current fish otoliths.

The only rationale for introducing the topic this way is that the alleged researchers plan to use their otolith research to prove or support climate alarmism.

Alleged research where the researchers ignore that oceans are not warming in a sense that causes fish to seek cooler water.

It is likely that these researchers assume that oceans are warming based upon sea surface temperatures which are not valid below the top surface of the ocean.
An assumption that calls the researchers into question as they appear to ignore reality in favor of their preferred confirmation bias.

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