Fredrik Jutfelt 🐠
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jutfelt.bsky.social
Fredrik Jutfelt 🐠
@jutfelt.bsky.social
4.2K followers 1.1K following 310 posts
Animal physiology, marine biology, fish, climate change, scientific integrity, science and academia. Professor @goteborgsuni.
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Fredrik Jutfelt 🐠 @jutfelt.bsky.social · Jun 28
FINclub research trip going well! 32 people, dozens of fish and invert species, 16 experiments, two dogs and lots of fun. Some photos in thread.
🧪🐟🦑
jutfelt.bsky.social
121 scientists from 27 countries! Join!
jutfelt.bsky.social Fredrik Jutfelt 🐠 @jutfelt.bsky.social · 8d
Interested in thermal biology? Please join our new and growing grass roots initiative, the Thermal Ecology Alliance, initiated by @patricepottier.bsky.social. 🧪🐟🦑🌡️

Sign up here: www.thermalecologyalliance.org#participation

Check who already signed up:
www.thermalecologyalliance.org#community
Fish embryos under the microscope
November 10, 2025 at 6:27 AM
jutfelt.bsky.social
Excellent article on the oxygen limitation during warming discussions, and our recent paper on the topic.

By @dianasmadeira.bsky.social 🐟🧪
plosbiology.org PLOS Biology @plosbiology.org · 4d
Oxygen limitation is considered a key mechanism of #ThermalTolerance. @dianasmadeira.bsky.social explores how a @plosbiology.org study challenges this idea, showing minimal protective effects of O2 supersaturation in heat-stressed #aquatic #ectotherms 🧪 Paper: plos.io/43hzMQa Primer: plos.io/3XeUtbS
The effects of temperature on organismal performance are depicted using thermal performance curves, where performance is greatest at the optimal temperature and starts to decrease toward cooler or warmer temperatures, reflecting the thermal window (tolerable range of temperatures) of the species. Briefly, the Oxygen and Capacity Limited Thermal Tolerance hypothesis proposes that oxygen limitation explains the performance decline at high temperatures and sets the first boundary for thermal limits across ectotherms. This is due to a mismatch between the oxygen demand of the organism and the capacity of the cardiorespiratory system to supply oxygen to tissues when the organism is under warming. This concept is central to predict species responses to warming. As oxygen supersaturation in water has been shown to alleviate oxygen supply limitations by increasing maximum rates of oxygen transport in blood, Raby and colleagues (2025) tested the effects of oxygen supersaturation on thermal tolerance across 14 aquatic species. The authors found that it had negligible effects on upper thermal limits, challenging the oxygen limitation hypothesis as a universal mechanism underpinning thermal tolerance of aquatic ectotherms. The authors highlight that oxygen supersaturation in water, a naturally occurring phenomenon in shallow waters, may not protect aquatic species from the effects of extreme heat.
November 7, 2025 at 2:38 PM
Reposted by Fredrik Jutfelt 🐠
jutfelt.bsky.social
Thanks to this amazing team @graham-raby.bsky.social
@jaydebon.bsky.social @zoe-storm.bsky.social @annahandreassen.bsky.social @emilyrlechner.bsky.social @erinmcstewart.bsky.social @leeuwisrobin.bsky.social @rasmusern.bsky.social @lorenasilvag.bsky.social @domroche.bsky.social
November 5, 2025 at 10:34 AM
Reposted by Fredrik Jutfelt 🐠
jutfelt.bsky.social
@rachaelmorgan.bsky.social @leon-at-sea.bsky.social

Link to the open access paper:
journals.plos.org/plosbiology/...
Oxygen supersaturation has negligible effects on warming tolerance across diverse aquatic ectotherms
Oxygen supersaturation in aquatic ecosystems has been proposed to buffer against heat stress in water-breathing animals. This study re-examines this question in a diverse panel of aquatic ectotherms, ...
journals.plos.org
November 5, 2025 at 10:34 AM
Reposted by Fredrik Jutfelt 🐠
plosbiology.org
Oxygen supersaturation is proposed to buffer against #HeatStress in water-breathing animals. @graham-raby.bsky.social @jutfelt.bsky.social &co re-examine this question in diverse #aquatic #ectotherms, showing that #hyperoxia has minimal impact on thermal tolerance @plosbiology.org 🧪 plos.io/43hzMQa
Effect of hyperoxia (150% air saturation) on warming tolerance in 14 aquatic ectotherms from across the globe. Left: Forest plot showing effect sizes (model estimates ± 95% confidence intervals) for the effect of hyperoxia on warming tolerance. Black symbols are the fast warming (0.3°C min−1) trials, blue symbols are the slow warming (1°C h−1) trials, and yellow symbols are for a net combined effect with random effects for subgroups of the 24 experiments. The effects were considered statistically significant where the 95% confidence interval does not cross the red vertical line. Right: Approximate geographical distributions for the 10 species of fish (top) and four species of decapod crustaceans (bottom) used in the laboratory experiments to assess the effects of hyperoxia on upper thermal tolerance.
November 6, 2025 at 8:55 AM
Reposted by Fredrik Jutfelt 🐠
plosbiology.org
Oxygen supersaturation is proposed to buffer against #HeatStress in water-breathing animals. @graham-raby.bsky.social @jutfelt.bsky.social &co re-examine this question in diverse #aquatic #ectotherms, showing that #hyperoxia has minimal impact on thermal tolerance @plosbiology.org 🧪 plos.io/43hzMQa
Effect of hyperoxia (150% air saturation) on warming tolerance in 14 aquatic ectotherms from across the globe. Left: Forest plot showing effect sizes (model estimates ± 95% confidence intervals) for the effect of hyperoxia on warming tolerance. Black symbols are the fast warming (0.3°C min−1) trials, blue symbols are the slow warming (1°C h−1) trials, and yellow symbols are for a net combined effect with random effects for subgroups of the 24 experiments. The effects were considered statistically significant where the 95% confidence interval does not cross the red vertical line. Right: Approximate geographical distributions for the 10 species of fish (top) and four species of decapod crustaceans (bottom) used in the laboratory experiments to assess the effects of hyperoxia on upper thermal tolerance.
November 5, 2025 at 5:35 PM
Reposted by Fredrik Jutfelt 🐠
jaydebon.bsky.social
Very happy and proud to see this one published! Have a look at this global assessment of the effect – or lack of effect – of extra oxygen (hyperoxia) on ectotherm thermal tolerance! Led by @graham-raby.bsky.social and a team of incredible collaborators working on multiple taxa 🐟 🐠 🦀 🦐.
jutfelt.bsky.social Fredrik Jutfelt 🐠 @jutfelt.bsky.social · 6d
Oxygen supersaturation has been reported to protect aquatic animals from heat waves. We tested this in a large collaborative experiment on many species of fish and crustaceans. Our new paper in @plosbiology.org shows that the effect of hyperoxia on thermal tolerance is negligible. Unfortunately.
November 5, 2025 at 3:19 PM
Reposted by Fredrik Jutfelt 🐠
plosbiology.org
Oxygen supersaturation is proposed to buffer against #HeatStress in water-breathing animals. @graham-raby.bsky.social @jutfelt.bsky.social &co re-examine this question in diverse #aquatic #ectotherms, showing that #hyperoxia has minimal impact on thermal tolerance @plosbiology.org 🧪 plos.io/43hzMQa
Effect of hyperoxia (150% air saturation) on warming tolerance in 14 aquatic ectotherms from across the globe. Left: Forest plot showing effect sizes (model estimates ± 95% confidence intervals) for the effect of hyperoxia on warming tolerance. Black symbols are the fast warming (0.3°C min−1) trials, blue symbols are the slow warming (1°C h−1) trials, and yellow symbols are for a net combined effect with random effects for subgroups of the 24 experiments. The effects were considered statistically significant where the 95% confidence interval does not cross the red vertical line. Right: Approximate geographical distributions for the 10 species of fish (top) and four species of decapod crustaceans (bottom) used in the laboratory experiments to assess the effects of hyperoxia on upper thermal tolerance.
November 5, 2025 at 2:07 PM
Reposted by Fredrik Jutfelt 🐠
zebrafishrock.bsky.social
🔗 to paper: journals.plos.org/plosbiology/...
November 5, 2025 at 10:41 AM
jutfelt.bsky.social
Oxygen supersaturation has been reported to protect aquatic animals from heat waves. We tested this in a large collaborative experiment on many species of fish and crustaceans. Our new paper in @plosbiology.org shows that the effect of hyperoxia on thermal tolerance is negligible. Unfortunately.
November 5, 2025 at 10:34 AM
Reposted by Fredrik Jutfelt 🐠
jutfelt.bsky.social
Interested in thermal biology? Please join our new and growing grass roots initiative, the Thermal Ecology Alliance, initiated by @patricepottier.bsky.social. 🧪🐟🦑🌡️

Sign up here: www.thermalecologyalliance.org#participation

Check who already signed up:
www.thermalecologyalliance.org#community
Fish embryos under the microscope
November 3, 2025 at 12:58 PM
Reposted by Fredrik Jutfelt 🐠
jutfelt.bsky.social
The first project, during 2026, will be a global distributed test of thermal tolerance in the embryos of fishes. We are hoping for many species from various environments and climates.

Please spread the word and join us!

www.thermalecologyalliance.org#home
TEA - Thermal Ecology Alliance
A global collaborative initiative assessing and mitigating the impacts of extreme temperature events on biodiversity.
www.thermalecologyalliance.org
November 3, 2025 at 1:00 PM
Reposted by Fredrik Jutfelt 🐠
zebrafishrock.bsky.social
For those interested 🐟🌡️
jutfelt.bsky.social Fredrik Jutfelt 🐠 @jutfelt.bsky.social · 8d
Interested in thermal biology? Please join our new and growing grass roots initiative, the Thermal Ecology Alliance, initiated by @patricepottier.bsky.social. 🧪🐟🦑🌡️

Sign up here: www.thermalecologyalliance.org#participation

Check who already signed up:
www.thermalecologyalliance.org#community
Fish embryos under the microscope
November 3, 2025 at 1:02 PM
jutfelt.bsky.social
Interested in thermal biology? Please join our new and growing grass roots initiative, the Thermal Ecology Alliance, initiated by @patricepottier.bsky.social. 🧪🐟🦑🌡️

Sign up here: www.thermalecologyalliance.org#participation

Check who already signed up:
www.thermalecologyalliance.org#community
Fish embryos under the microscope
November 3, 2025 at 12:58 PM
Reposted by Fredrik Jutfelt 🐠
leeuwisrobin.bsky.social
You can use HusMorph to analyse images of fish — like the above example — or whatever your favourite study organism is 🐟🦐🥬 See our Toolbox paper in Conservation Physiology @conphysjournal.bsky.social for more info: doi.org/10.1093/conp....
October 24, 2025 at 4:10 PM
jutfelt.bsky.social
Sign the statement to prohibit development of superintelligence!

superintelligence-statement.org
Statement on Superintelligence
“We call for a prohibition on the development of superintelligence, not lifted before there is (1) broad scientific consensus that it will be done safely and controllably, and (2) strong public bu...
superintelligence-statement.org
October 30, 2025 at 12:25 PM
Reposted by Fredrik Jutfelt 🐠
leeuwisrobin.bsky.social
Tired of manually landmarking hundreds of images? 📍🖼️😩 Our lab developed HusMorph, a free and open-source tool that automates morphometric landmarking using #MachineLearning — no coding required. Simply train the model on your images, and it quickly places landmarks with human-level accuracy. #AI
October 24, 2025 at 4:10 PM
jutfelt.bsky.social
Check out our new methods paper for automated length and body shape measurements in animals!
conphysjournal.bsky.social Conservation Physiology @conphysjournal.bsky.social · 18d
Ever needed to measure the morphological features of your organism across hundreds of images? 🤯 HusMorph uses #MachineLearning to detect morphological landmarks in the image, speeding up your #ImageAnalysis time!

Read it here: doi.org/10.1093/conp...
October 24, 2025 at 1:16 PM
jutfelt.bsky.social
Sad that ChatGPT makes up two male scientists instead of the real scientists Andrea Franke and Catriona Clemmesen.
October 21, 2025 at 12:54 PM
jutfelt.bsky.social
I think my PhD students want me to resign
Post it note saying please re-sign
October 13, 2025 at 3:57 PM
jutfelt.bsky.social
What's the best free software for behavioural tracking?
(videos of several fish in a shared arena)

Toxtrac?
Tractor?
Trex?
idTracker ai?
Detect+Track?
AnimalTracker?
Other?

Please help 🙏
October 3, 2025 at 1:21 PM
jutfelt.bsky.social
www.nature.com/articles/s44...
Near complete local extinction of iconic anemonefish and their anemone hosts following a heat stress event - npj Biodiversity
npj Biodiversity - Near complete local extinction of iconic anemonefish and their anemone hosts following a heat stress event
www.nature.com
September 26, 2025 at 2:48 PM
jutfelt.bsky.social
I spend most of my time on research and I try to keep the teaching load down. But WOW, it is so inspiring when you meet students like this! Teaching ethics and robust open science practices to the new MSc cohort has been treat.
September 26, 2025 at 12:32 PM
jutfelt.bsky.social
Notice anything fishy here?
#ImageForensics
🐟🧪
(Too easy for you @elisabethbik.bsky.social)
September 23, 2025 at 12:21 PM
jutfelt.bsky.social
Cleaned out my office at NTNU, exactly 10 years after moving in. Looking at the list of people who passed through the lab, so many great scientists and friends!

www.gu.se/en/research/...

Yes, I feel a little sentimental.
September 15, 2025 at 8:59 PM