From Live Science
By Brandon Specktor, Senior Writer | December 7, 2018 03:43pm ET
Australian researchers recently bred Port Jackson sharks in a tank warmed to a temperature likely to occur at the end of the century if climate change continues unabated. These warmer waters made the sharks right-handed.
Credit: Shutterstock
Australian scientists went snorkeling for shark eggs, then incubated those eggs in a special tank designed to simulate the hot, end-of-century temperatures expected to prevail if climate change continues unabated. Half of the sharks died within a month. The other half became right-handed.
The team of biologists from Macquarie University in Sydney knew from previous research that warming ocean temperatures alter the way fish grow and develop. The researchers wanted to find out whether these changes would also affect fish behavior — specifically, whether sharks raised in a tank warmed to projected end-of-century temperatures would show a preference for swimming one direction or another when faced with a Y-shaped pathway. Basically, could global warming make sharks right- or left-handed?
Sharks, you may be tempted to point out, don’t actually have hands (they have fins, which are genetically not so far off from human arms). So, when scientists talk about the right or left “handedness” of sharks and other marine creatures, they’re talking about lateralization: the tendency for one half of an animal’s brain to automatically control certain behaviors. With simple, automated behaviors (say, your preference for writing with your right or left hand), this theoretically frees up mental energy for an animal to perform more-complex cognitive functions. In fish, lateralization might mean a default preference for swimming a certain way, which can help those fish forage for food or form schools. [On The Brink: A Gallery of Wild Sharks]
“Since behavioral lateralization is an expression of brain function, it can be used as a barometer of normal brain development and function in some contexts,” the researchers wrote in a study published this summer in the journal Symmetry. “Namely, exposure or development under climate change conditions.”
Right shark or left shark?
To test whether warmer waters could force a shark to become lateralized, the researchers collected a clutch of Port Jackson shark eggs from the waters off of eastern Australia. The scientists incubated 12 eggs in a tank warmed to the current ambient temperature of the bay (about 70 degrees Fahrenheit, or 20.6 degrees Celsius) and 12 others in a tank that was gradually warmed to 74.5 degrees F (23.6 degrees C) to simulate those predicted end-of-century ocean temperatures.
Five sharks incubated in the elevated temperatures died within a month of hatching. To test whether the remaining sharks had developed lateralization, the team placed each of those animals in a long tank with a Y-shaped partition at one end. Behind the partition was a food reward; sharks just had to decide whether to swim to the right or left side of the Y to reach their snack.
The authors found that sharks incubated in the elevated temperatures showed a strong preference for turning right. The sharks in the control group showed no preference one way or the other.
Read the rest of the story here.
HT/Willis
Is it possible that a mommy shark could swim to a cooler place? Are they self-aware enough to know they can swim?
What species of shark is that in the photo? Anyone know? Shutterstock did not identify it.
It is an Australian Port Jackson Shark (Heterodontus portusjacksoni) — Port Jackson is the official name of Sydney Harbour. It is a migratory species, traveling south in the summer and returning north into warmer waters to breed in the winter. As you can see by its mouth structure, it feeds mainly on hard-shelled molluscs, crustaceans, sea urchins, plus some fish. It is not a killer and can be tamed in captivity.
Anyone with more than 2 brain cells might think that being migratory, it could easily select a water temperature suitable to nurture itself and its offspring.
Sharks have hands?
Sharks are the worst kind of pickpockets, pilferers and car burglars. There used to be a sign in the Tomales Point trailhead car-park at the Point Reyes National Seashore that read “Warning: Great White Shark area. Do not leave valuables in your car.”
So did the sharks become “right-handed” and die when temperatures were much warmer in the past. If not, why not? I’m calling BS on this story.
I remain curious still, what does a sharks “hand” look like?
5 Aces.
Those who even thought up this crap should be thrown behind bars for 1, molesting wildlife, 2 trying to convince people that this shit is serious and 3, just because it will make me feel better.
So,
if I understand this correctly, they had 12 sharks in the hot tank and 5 were ‘unable to continue’ to testing. This left 7 which then showed a ‘strong preference’ to turning right. Which is? 7 out of 7? 6 out 7? 5?
Assuming they have set up their tests correctly the left/right test should be 50/50. Assuming. Anyone ever studied fully the factors that affect a shark tank?
However, with only 7 sharks and a basic 50/50 getting all 7 to go Right is not that unusual. Unlikely, but I would like to see someone who understands probability more demonstrate this is not just noise.
So, assuming this isn’t just noise, let us look at one of the conclusions: hotter water forces sharks to develop an energy saving method.
Sorry, but what? You conclude that from ONE generation and a sample size of 7? Yeah… of course…
Then, if you are still playing at home, comes the realisation that the purpose of this research was to determine if sharks were left or right handed and then cook them to see if they could modify this. This was their end game. This, apparently, is what Climate Research is all about.
However there is one important fact these ‘researchers’ failed to comment on that is perhaps the most important observation of them all.
Sharks will survive in warmer waters!
True some of them died, but the point is that some of them didn’t. They will survive. 3 degs C will not instantly kill off sharks, so the 2 deg screamed by the IPCC is clearly also not a threat.
Warming seas? Nothing to worry about. This research has shown that.
How well did they control the currents and eddies in the pool?
Sharks are extremely sensitive to finding food – A shark can sniff out fish extracts that make up only one part for every 10 billion parts [source: Elasmodiver] https://animals.howstuffworks.com/fish/sharks/shark-senses1.htm .
Were those who performed the experiment able to measure the concentration of the smell of the food to within 1/10,000,000,000 at all points in the tank to assure that the right and left paths both had the exact number of molecules of the food throughout the water path?
If not, then it isn’t a valid study.
Also, if one is to assume it is a valid study, since humans tend to exhibit a strong tendency toward right-handedness, does that mean that humans are “left with physically smaller brains than other animals” and “have less mental energy to spare?”
The sharks were Marxist. They wanted to end up on the right side of history. Which is why they ended up going around in circles.
Out of interest, has anybody calculated the amount of energy required to raise the surface water temp in Port Jackson (and presumably entire Pacific) by 3C?
I did not realize that sharks had right hands.