As we continue to change the worlds oceans and alter marine habitats, cephalopods are booming. Numbers of octopuses, squid, and cuttlefish have been consistently on the rise over the last six decades, according to new findings published in Current Biology this week.
Cephalopods boast a unique define of traits that allow them to adapt speedily to changing conditions.They have rapid growth, short lifespans, and flexible physiologies. In fact, some consider them the “weeds of the sea.” But the impacts of cephalopod dynamics on marine food webs are hard to predict. Not only are they voracious predators, theyre also a key source of food for many other species, including humen. Cephalopod fisheries are reporting improved catches, for example, but recent observations show declines in giant Australian cuttlefish( pictured above) at their breeding ground in South Australias Spencer Gulf.
To investigate long-term trends in abundance, University of Adelaides Zo Doubleday and colleagues have assembled a global database of cephalopod catch rates catch per unit of fishing or sampling effort from 1953 to 2013. They analyse 35 different species or genu spanning six cephalopod families living in all major oceanic areas in both hemispheres: 52 percentage squid, 31 percentage octopuses, and 17 percent cuttlefish and their close relatives, the bobtail squid.
The team found that cephalopod populations are enjoying a global proliferation. Even cuttlefish numbers from South Australia are ricochetting back. “The consistency was the biggest surprise, ” Doubleday says in a statement. “Cephalopods are notoriously variable, and population abundance can fluctuate wildly, both within and among species. The fact that we find consistent, long-term expanded in three diverse groups of cephalopods, which inhabit everything from boulder ponds to open oceans, is remarkable.”
The team is now looking into the factors responsible for this increase. Warmer temperatures are thought to accelerate cephalopod life cycles, for example, and its own population have also increased in areas where fish have declined due to overfishing.
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