Human marine activity causes cephalopod surge

Although human interaction has reduced the population of many marine organisms over recent years, it appears to have boosted cephalopod numbers.

Members of this class include octopuses, cuttlefish and squid and recent studies suggest a significant increase in their numbers over the last six decades.  Scientists captured this data by measuring ocean catches between 1953 and 2013 that included cephalopods. More than 30 species were counted by the researchers in the data collated.

Zoë Doubleday, first author of the study from the University of Adelaide, said: "Cephalopods are notoriously variable and population abundance can fluctuate wildly, both within and among species. The fact that we observed consistent, long-term increases in three diverse groups of cephalopods, which inhabit everything from rock pools to open oceans, is remarkable."

Already known for rapid growth, short lifespans and extra sensitive physiologies, researchers believe that these properties allow cephalopods to adapt more quickly than other marine species to changes in the environment. Prey species, which include commercially valuable fish and invertebrates, could be affected by the surge in cephalopod numbers, which could also benefit predators that rely on them for food.

Researchers are unable to predict what could happen in the future and have decided to look into the factors responsible for such a large rise in cephalopod numbers. They hope this may be able to paint a better picture of how human activities are changing the oceans.

The research was published in Cell.