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.”
“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.
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.”
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.
“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.”
