Biology

Climate change may cause an increase in squid populations

Climate change may cause an in...
Dr. Blake Spady observes one of the squid, which is doing surprisingly well in acidic water
Dr. Blake Spady observes one of the squid, which is doing surprisingly well in acidic water
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Dr. Blake Spady observes one of the squid, which is doing surprisingly well in acidic water
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Dr. Blake Spady observes one of the squid, which is doing surprisingly well in acidic water

Climate change already appears to be responsible for an overabundance of jellyfish in the world's oceans, but new research indicates that it may also lead to something else – lots and lots of squid. The findings run contrary to what was expected to be the case.

As global warming causes the seas to warm, increased carbon dioxide content in the water causes it to become more acidic. Squids' blood is very sensitive to changes in acidity, so it had been thought that ocean acidification would negatively affect their aerobic performance. As it is, the animals' swimming technique is very energy-intensive, requiring a great deal of oxygen to be absorbed and transported by their cardiovascular system.

To test how well they might fare in the future, scientists at Australia's James Cook University placed multiple two-toned pygmy squid and bigfin reef squid in continuous-flow water tanks, and kept the two species there for a period equivalent to approximately 20 and 36 percent of their lifespans, respectively. The CO2 concentration of the water had been raised to a level that is expected for the world's oceans, by the end of the century.

Surprisingly, even after performing "exhaustive exercise" for sustained periods, the cephalopods' aerobic performance and recovery remained unaffected. This adaptability was thought to be due to better-than-expected blood oxygen binding, and it could not only allow squids to survive climate change, but it may even result in a population boost – some of their key predators have been proven to be negatively affected by acidification.

"We think that squid have a high capacity to adapt to environmental changes due to their short lifespans, fast growth rates, large populations, and high rate of population increase," says lead scientist Dr. Blake Spady. "We are likely to see certain species as being well-suited to succeed in our rapidly changing oceans, and these species of squid may be among them. The thing that is emerging with most certainty is that it's going to be a very different world."

A paper on the research was recently published in the journal Conservation Physiology.

Source: ARC Centre of Excellence for Coral Reef Studies at James Cook University

6 comments
Joshua Tulberg
Interesting, but a bit of a let-down that their population growth is credited as a result of their biggest predators dying. If climate change results in a decrease in Human population, then we (humans) would be stylin'. Not just the squids.
f8lee
But it turns out cephalopods are quite intelligent - perhaps they are destined to be the next "king of the evolutionary mountain" - while humans are futilely trying to battle SkyNet (or whatever our computer overlord calls itself in 20 years).
Jose Gros
Squids are tasty to eat, but some reach a 60 kg weight, and behaved in an aggressive way against swimmers and divers. The movie by Jacques Cousteau, inventor of autonomous system for scuba divers, on their ship 'Calypso': 'Secrets of the Sea', depicts a huge squid capture, after some days, all crew members rejected in disdain when offered squids. 'The night of squids'
piperTom
The article claims something "in the water causes it to become more acidic." The sea cannot be MORE acidic, since it is not acidic at all. In general, the pH of the sea is 8.0, which is alkaline. That's down from an historic pH of 8.1, so you could claim it's less alkaline or more neutral, but we don't see than because it doesn't sound scary. We have now 25 years of panicky warnings about "climate catastrophe" and it's always 20 (or, here, 80!) years away. The many climate models used by the IPCC, from which we "expect" acid seas in 80 years, are fine, except for disagreement with actual data collected in last couple of decades.
techmanmacho
I can hear the commercial now..."Squid, it's what's for dinner."
MJBadagliacco
Change is inevitable... We are the arrogant bunch aren't we? We believe that because we are here we can save everything from changing if we just try hard enough... Sorry, does not work that way! Change will come, does not matter what we do! It is a NATURAL thing that occurs. WE are part of the Natural course... WE ARE part of the eco-system... We are NOT evil humans that are creating havoc. We are just part of the natural evolution of the planet!