Study: Octopus and Squid Populations Are Booming, Called ‘Weeds of the Sea’

By Giuliana Manca, Epoch Times
May 23, 2016 6:24 pm Last Updated: May 23, 2016 6:24 pm

While many species of marine life are facing an unprecedented decline in population, one group of underwater critters are seeing a global increase. 

Cephalopods—octopus, squid, and cuttlefish—are thriving. A study published on May 23 in Current Biology indicates that since 1953, the number of cephalopods has increased. 

The paper’s lead author, Dr Zoë Doubleday, noted that cephalopods are often called “weeds of the sea.”

Doubleday, a research fellow at the University of Adelaide, said: “They have a unique set of biological traits, including rapid growth, short lifespans, and flexible development.”

This image provided by courtesy of NOAA Office of Ocean Exploration and Research, Hohonu Moana 2016, shows a possible new species of octopus. Scientists say they have discovered what might be a new species of octopus while searching the Pacific Ocean floor near the Hawaiian Islands. Michael Vecchione of the National Oceanic and Atmospheric Administration says in a statement Friday, March 4, 2016, that on Feb. 27 a team found a small light-colored octopus at a depth of about 2.5 miles in the ocean near Necker Island. (NOAA Office of Ocean Exploration and Research, Hohonu Moana 2016 via AP)
This image shows a possible new species of octopus. (NOAA Office of Ocean Exploration and Research, Hohonu Moana 2016 via AP)

“These allow them to adapt to changing environmental conditions more quickly than many other marine species,” said Doubleday. 

Doubleday hypothesizes that multi-limbed creatures could actually be benefiting from the changing ocean environment. 

A blue-ringed octopus. (via Toutiao)
A blue-ringed octopus. (via Toutiao)

The discovery was made quite by accident. Researchers compiled the worldwide cephalopod  to investigate the declining numbers of Giant Australian Cuttlefish. 

The International Union for Conservation of Nature (IUCN) categorizes the Giant Australian Cuttlefish as “near threatened.”

Cuttlefish on isolated black background
Cuttlefish

The data analyzed spans across six decades—from 1953 to 2013—and covers all the major oceans.

What Doubleday thought most remarkable, was the consistency of the population increase. 

“Cephalopods are notoriously variable, and population abundance can fluctuate wildly, both within and among species,” explained Doubleday. 

Scientists, however, are unsure what is triggering the proliferation.

Bobtail squid burying itself in sand at Seraya in Bali, Indonesia. (Matthew Oldfield)
Bobtail squid burying itself in sand at Seraya in Bali, Indonesia. (Matthew Oldfield)

“It is a difficult, but important question to answer, as it may tell us an even bigger story about how human activities are changing the ocean,” noted Professor Bronwyn Gillanders, another researcher involved in the study.

“Cephalopods are an ecologically and commercially important group of invertebrates that are highly sensitive to changes in the environment,” explained Gillanders. “Global warming and overfishing of fish species are two theories.”

 two-month-old octopus (Octupus Vulagaris) tries to unscrew the lid of a jar to get hold of its content, a crab, 23 June 2004 at Denmark's Aquarium in Copenhagen. (JORGEN JESSEN/AFP/Getty Images)
A two-month-old octopus (Octupus Vulagaris) tries to unscrew the lid of a jar to get hold of its content, a crab, 23 June, 2004, at Denmark’s Aquarium in Copenhagen. (JORGEN JESSEN/AFP/Getty Images)