Over the last 60 years or so, populations of the world’s cephalopods–squids, cuttlefish, and octopus–have been climbing. That sounds like a wonderful thing, especially for those of us who enjoy some fried calamari or octopus from time to time (we shouldn’t). But as this recent study in Current Biology reports, the population boom may be a sign of worse things to come. For one thing, the rising number of cephalopods may be yet another sign of climate change driven by human activities:

Numerous studies demonstrate that cephalopod populations are highly responsive to environmental change, with anthropogenic climate change, especially ocean warming, a plausible driver of the observed increase. Elevated temperatures, for instance, are thought to accelerate the life cycles of cephalopods…

Again, this sounds like great news for the ocean dwellers and any predators–including humans–that feed on them, but other changes beyond the unpredictable population swells are taking place. As a Scientific American conversation on this study notes, “a strong hot season of El Niño followed by a cold season of La Niña” can result in Humboldt squid that grow up to 88 pounds, ten times their normal size.

The complex oceanic systems strongly suggest that more than one cause is responsible for the rising populations of the members of the molluscan class. Another culprit may be the fishing industry and over-exploitation practices:

Further, it has been hypothesised that the global depletion of fish stocks, together with the potential release of cephalopods from predation and competition pressure, could be driving the growth in cephalopod populations. It is relatively well documented that many fish species have declined in abundance due to overfishing, and several regional studies have suggested that cephalopod populations have increased where local fish populations have declined.

With human activity being the likeliest contender for the rise in the world’s cephalopod population, the best answer we have for controlling it is proper management of fish stocks and carbon emissions, lest we find our oceans awash with ever-greater numbers before the ultimate collapse of some of the world’s oldest, most intelligent, and most successful species.

Or perhaps the minions of Cthulhu are merely preparing for world domination, and our time on this good Earth is coming to an end. Either one.

Image: By Pierre Denys de Montfort († 1820) – Ellis, R. 1994. Monsters of the Sea. Robert Hale Ltd.; By Anonymous (Bulletin of the United States Fish Commission)