Guest essay by Eric Worrall
Who feels sad about the fate of the poor lost baby fish?
Baby fish may not find their way home as the level of CO2 in the ocean rises, study finds
…
University of Adelaide Professor Ivan Nagelkerken said some species of fish larvae relied on sounds in the ocean to find their way between open areas and shallow water.
When larvae grow big enough, they find their way to their natural habitats along the coastlines.
“A lot of larvae have evolved to use certain cues to help them find their new homes … including sounds,” Professor Nagelkerken said.
“It’s a very reliable, directional cue that can help them to navigate to find these homes.”
…
The research compared the behaviour of barramundi larvae in normal water to water with elevated CO2 levels similar to those predicted for the end of the century.
The right sounds would have led the barramundi to their natural habitat — tropical estuarine mangroves.
Instead, they were attracted to different sounds and white noise, leading them to habitats that were not beneficial to their survival.
…
“When we raised these larvae under elevated CO2, we saw that those larvae were no longer attracted — and worse, they were deterred by — the natural sounds of their natural habitat,” he said.
…
Read more: http://www.abc.net.au/news/2018-04-12/baby-fish-may-not-find-their-way-home/9643356
The abstract of the study;
On the wrong track: ocean acidification attracts larval fish to irrelevant environmental cues
Tullio Rossi, Jennifer C. A. Pistevos, Sean D. Connell & Ivan Nagelkerken
Population replenishment of marine life largely depends on successful dispersal of larvae to suitable adult habitat. Ocean acidification alters behavioural responses to physical and chemical cues in marine animals, including the maladaptive deterrence of settlement-stage larval fish to odours of preferred habitat and attraction to odours of non-preferred habitat. However, sensory compensation may allow fish to use alternative settlement cues such as sound. We show that future ocean acidification reverses the attraction of larval fish (barramundi) to their preferred settlement sounds (tropical estuarine mangroves). Instead, acidification instigates an attraction to unfamiliar sounds (temperate rocky reefs) as well as artificially generated sounds (white noise), both of which were ignored by fish living in current day conditions. This finding suggests that by the end of the century, following a business as usual CO2 emission scenario, these animals might avoid functional environmental cues and become attracted to cues that provide no adaptive advantage or are potentially deleterious. This maladaptation could disrupt population replenishment of this and other economically important species if animals fail to adapt to elevated CO2 conditions.
Read more: https://www.nature.com/articles/s41598-018-24026-6
According to the body of the text, the study was conducted in a big fish tank.
In my opinion the premise of this study is absurd. You can’t draw meaningful conclusions about the impact of a century of gradual change by dropping fish into an elevated CO2 environment and seeing which way they swim.
Even if the apparent confusion was caused by CO2 rather than contaminants or problems with the sound equipment, over the next eighty years fish will have plenty of opportunity to adapt to changed conditions – an opportunity not afforded to the unfortunate baby fish which participated in this experiment.
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..Baby fish may not find their way home as the level of CO2 in the ocean rises, study finds..University of Adelaide Professor Ivan Nagelkerken said some species of fish larvae relied on sounds in the ocean to find their way between open areas and shallow water…
Don’t tell me. They put the fish in fizzy soda water and the noise of the bubbles drowned out their mothers calling them home…?
Science is lost. It can’t find it’s way home.
Anybody in for crowdfunding the movie ‘Finding Science’ ?
Sound travels well in water. Sound reflects off of smooth tank sides.
How the heck did the poor fish knew exactly where the sounds were coming from?
Any change is extremely dangerous. Ocean sounds have never changed since God created the world 4,721 years ago. At least according to the University of Adelaide, which undoubtedly runs only on renewable electricity.
Playing in my world now, the Centropomidae, snooks and barramudi. Centropomidae live in tough environments especially as juveniles. Adult Centropomindae, move close to the mouths of estuaries and lagoons to spawn. The eggs and larvae are briefly planktonic then use tidal currents to move up the estuaries to shallow water, creeks, rivers, coastal marshes primarily to avoid predation from larger fish. Interestingly most of those juvenile habitats are more acidic and generally much hotter then the oceans and estuaries where they were spawned. Why CO2 would play any role, even assuming acidification, is way beyond me. Centropomindae larvae are hard to keep alive in captivity. In experiments conducted in Florida the controls were as hard to keep alive as the test larvae.
“Baby fish may not find their way home as the level of CO2 in the ocean rises…”
I blame the schools.
I have yet to see someone write a paper discussing the elephant in the room with regards to noise/impulse stimulation on aquatic environments. That particular elephant being offshore or near shore wind-farms. Multiple wind turbines producing varying pulse rates over time and all producing non-synchronized inputs at a given time should be playing havoc on marine species that rely on or utilize sound or electrical impulse derived communication or stimulus. You may be able to call it white noise if you are blind but it’s probably better suited to call it a black roar from a fish’s point of view. Has no one looked for the elephant? Probably not as an elephant in the room is hard to see through a microscope while trying to find C02.
Hell, there are two herds in the room and only one group are elephants. The other have microscopes but haven’t seen any elephants.
I thought the larvae just followed the trial of funding.
(The alarmists … not the fish.)
*trail
(CO2 has ruined my spelling.)
You just got ahead of yourself, the trials will come later.
Pretty certain this is another bit of recycled alarmist pap.
Climate science has destroyed Darwin. NOTHING can adapt now and nothing should ever have to. I don’t know whether to cheer or cry.
CO2 enhances scientists ability to smell grant money.
“You can’t draw meaningful conclusions about the impact of a century of gradual change by dropping fish into an elevated CO2 environment and seeing which way they swim. ”
True but you CAN get paid for doing it!
Ding, Ding, Ding!
We have a Winner!
“Ocean acidification alters behavioural responses to physical and chemical cues in marine animals, ”
Ocean pH varies a lot more than the drop expected in 100 years. These guys use an estimate equivalent to atmospheric co2 getting up to 4 times higher because of hypoxia. Even in ideal conditions almost half head off in the wrong direction and not a lot changes under extreme conditions. Just enough to justify the claim, barely.
Wouldn’t the glass walls of the tank stop them finding their way home?
So those evil denialists are [fish] child abusers! Shame shame shame.
The professor does not mention how he increased the level of CO2 or what pH level he created in his fish tank. Sea water currently averages 8.3 pH (which is nowhere close to acidic) and there is already significant variation in sea water pH by loacation, season and time of day.
Sea water is a well buffered solution, which will maintain its pH level in spite of CO2 absorption on the surface. I am curious how the professor reduced the pH of sea water to make it acidic.