A new study finds that squid, octopus, and cuttlefish are on the rise in the world’s oceans.

Scientists have noticed a huge growth in population for cephalopods, often referred to as the “weeds of the sea,” even as most other fish species are declining, according to a University of Adelaide statement.

The trend has been noticeable for the past 60 years, and has been consistent across all cephalopod groups.

Cephalopods have a unique advantage, including that ability to grow rapidly, have flexible development, and short lifespans that allow them to be more flexible and survivable in evolutionary terms. As a result, they’re better able to handle sudden shocks in the environment, such as a warming of the oceans from climate change.

The research was actually prompted by the decline of a cephalopod called the giant Australian cuttlefish. After looking into it, scientists found that not only was this species making a big comeback, but many other cephalopods were as well.

Unfortunately, this might be bad news for our planet, indicating that conditions are getting worse for the vast majority of sea life.

“Cephalopods are an ecologically and commercially important group of invertebrates that are highly sensitive to changes in the environment,” Project leader Professor Bronwyn Gillanders said in the statement. “We’re currently investigating what may be causing them to proliferate – global warming and overfishing of fish species are two theories. 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.”

Added lead author Dr Zoë Doubleday, Research Fellow in the Environment Institute and School of Biological Sciences: “There has been a lot of concern over declining numbers of the iconic Giant Australian cuttlefish at the world-renowned breeding ground in South Australia’s Spencer Gulf. To determine if similar patterns were occurring elsewhere, we compiled this global-scale database. Surprisingly, analyses revealed that cephalopods, as a whole, are in fact increasing; and since this study, cuttlefish numbers from this iconic population near Whyalla are luckily bouncing back.”