Climate Change and Growing Populations of Purpleback Squid

admin Invertebrate Zoology

Purpleback squid, or Sthenoteuthis oualaniensis,  are mollusks of the class cephalopoda. Cephalopods are are cephalized and have a modified foot that makes up their tentacles. Cephalopods are different from most other mollusks in that they have secondarily lost their shells. The nautilus is a cephalopod who has kept the shell, pictured below.

By Manuae (Own work) [CC BY-SA 3.0 (], via Wikimedia Commons

The nautilus has a shell, right side of the picture. It also has tentacles which are a modification of the foot structure found in all mollusks.







Other cephalopods have lost this shell, as can be seen in this picture of a purpleback squid. Photographer not named.


The purpleback squid has no shell, like other cephalopods, and instead uses secretions of ink to escape predators.






This species is one of the most abundant, if not the most abundant, large squid in the Indo-Pacific region. They tend to stay around 90 nautical miles from shore, at least until recently when they have been found along the coasts in unprecedented concentrations. Many have called for increased research on the effect of climate change on population increases in certain species. People have compared this phenomenon of jellyfish blooms that seem to happen more frequently as the climate changes.

These squids are caught in fisherman’s gill nets and thus can severely decrease the amount of fish they can bring in. Though some areas do export these organisms, the areas who are experiencing these organisms in this concentration for the first time have not implemented any trade involving purpleback squids as of 2016. There have been many reports of unusually high concentrations of purpleback squid around many areas of the Arabian sea.

Those who seek to trade in the new found commodity could make a prosperous business from new development. But, this only makes me think “what is next”. This business could be completely destroyed if the population of squids shrinks with increased change in climate. Or, the population could grow out of control and ruin the ecosystems they inhabit. This problem, and many others, involving climate change need to be researched thoroughly in order to understand what is happening now. Also, we need to be able to predict what can happen, so preparations can be made.

Feature Image: Photographer not named.


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