Rising carbon dioxide levels messes with squid's hunt for prey

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Rising carbon dioxide levels messes with squid's hunt for prey

March 22, 2018 - 17:14
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A new study has shown how the squid's hunting ability is affected by rising levels of carbon dioxide in the ocean.

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High carbon dioxide (CO2) levels in the ocean make squid less proficient hunters, according to a study by the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

Led by PhD candidate Blake Spady from Coral CoE, the study focused on the effects of elevated CO2 on the hunting behaviour of cephalopods, represented in the study by the pygmy squid and bigfin reef squid.

The team had chosen to focus on cephalopods as, compared to fish, the effects of elevated CO2 on these highly active invertebrates is largely unknown.

The results indicated that the functions of the two species were indeed affected by elevated levels of CO2.

Behavourial effects

According to co-author Dr Sue-Ann Watson, “Overall, we found similar behavioural effects of elevated CO2 on two separate cephalopod orders that occupy largely distinct niches. This means a variety of cephalopods may be adversely affected by rising CO2 in the oceans, and that could have significant consequences in marine ecosystems."

"For pygmy squid, there was a 20% decrease in the proportion of squid that attacked their prey after exposure to elevated CO2 levels. They were also slower to attack, attacked from further away, and often chose more conspicuous body pattern displays at elevated CO2 conditions," said Spady.

He added that the bigfin reef squid showed no difference in the proportion of individuals that attacked prey. In addition, there was increased activity at elevated carbon dioxide conditions when the two species were not hunting, suggesting that they could be adversely altering their "energy budgets."


Spady added that squid might have the potential to adapt to rapid changes in the physical environment due to their short lifespan, large population and high rate of population increase, saying, “The fast lifestyle of squid could mean they are more likely to adapt to future ocean conditions than some other marine species, and this is the next question we intend to investigate.”

The study was published in the recent issue of the journal Global Change Biology.

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