According to a study published by the University of Adelaide, the number of octopus, squids, and other cephalopods has skyrocketed since the 1950s. Scientists suspect that climate change and overfishing may be two probable causes.
While most fish species are on a declining trend, cephalopods seem to be thriving despite the changes brought to the ocean in the last several decades. Researchers sifted through data on cephalopod catches around the globe and concluded that the marine animals’ numbers have consistently increased over the last 60 years.
Dr Zoë Doubleday, lead author of the study and senior researcher with the Australian university’s Environment Institute, noted that at least three separate groups of cephalopods have increased in numbers.
Doubleday said that it is no wonder that squids and octopus are called “weeds of the sea.” Just like weeds, these marine creatures grow rapidly despite their short lifespan, and they have a high flexibility as they develop.
These traits help cephalopods adapt to changes in their habitat including rising sea temperatures like few other animals. In fact, warming oceans seem to actually help them thrive.
Doubleday’s team started investigating the status of cephalopods following a previous study looking into the declining numbers of the Giant Australian cuttlefish. The researchers were concerned that the iconic creature may soon go extinct, so they compiled a global database comprising nearly all cephalopods.
To their surprise, the recent analysis showed that the numbers of cephalopods aren’t dwindling and cuttlefish populations in Australia are actually experiencing a rebound.
Professor Bronwyn Gillanders, who was also involved in the latest study, believes that the recently observed phenomenon may be due to human activities which alter the marine environment and its denizens.
Gillanders noted that cephalpods are not only important for biodiversity but also for commercial purposes. The invertebrates seem highly sensitive to any changes brought to their habitats.
As a follow-up, the team plans to learn what may be driving up the numbers of cephalopods worldwide. The team has at least two hypotheses: overfishing and global warming. The research could also help scientists better understand how climate change alters marine ecosystems on the long run.
The study was published this week in the journal Current Biology.
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