Squid and octopus count increasing despite drop in global fish count
A study published in Current Biology and reported on in The New York Times has shown that the global population of cephalopods – a class of mollusks that include squid, octopus and cuttlefish – is increasing, even as a separate World Wildlife Fund report posited that the world’s fish population declined by nearly half between 1970 and 2012.
The study, led by University of Adelaide (Australia) marine ecologist Zoë Doubleday, investigated 35 cephalopod species, including demersal, benthopelagic and pelagic species over a 60 year timeline from 1953 to 2013. The species chosen for the study can be found most global marine ecosystems, according to the article.
“Cephalopods have increased in the world’s oceans over the last six decades,” Doubleday told The New York Times. “Our results suggest that something is going on in the marine environment on a large scale, which is advantageous to cephalopods.”
Doubleday said she suspects that climate change and overfishing are two potential causes of the boom in cephalopods, as warmer oceans may be creating more welcoming conditions, and overfishing could be reducing the number of their predators.
Further studies exploring the large-scale population shifts between marine species, “may tell us an even bigger story about how human activities are changing the ocean,” Doubleday said.