Environment

Brainless but not directionless, jellyfish swim against the current

Brainless but not directionles...
Scientists have found that jellyfish don't always go with the flow (Photo: Shutterstock)
Scientists have found that jellyfish don't always go with the flow (Photo: Shutterstock)
View 2 Images
A diver tagging a jellyfish in waters off France
1/2
A diver tagging a jellyfish in waters off France
Scientists have found that jellyfish don't always go with the flow (Photo: Shutterstock)
2/2
Scientists have found that jellyfish don't always go with the flow (Photo: Shutterstock)

For many people, jellyfish are just an unwelcome addition to a day at the beach. But the gelatinous creatures can seriously affect commercial fishing ventures and even cause the shutdown of power stations when they form into giant "blooms" in the ocean. Researchers at Deakin University in Australia, might be on the way to a solution.

Jellyfish blooms are enormous groupings of the gently floating creatures and their numbers have been on the increase in recent years. The blooms can present serious problems, even though they are necessary for the ecosystem and a good food source for many creatures, such as Leatherback Turtles. In 2013, facing increasing numbers of the creatures, Korea dispatched jellyfish-shredding robots to cut down the population.

It might sound cruel, but the creatures do not have brains or hearts, which is why the discovery by the team was so surprising. They found that jellyfish can not only detect the ocean’s currents, but swim against them. Other much more evolved sea creatures, like turtles, cannot. They may not be the passively floating things of popular imagination.

Professor Graeme Hays, from Deakin and scientists from Swansea University, tracked free-ranging barrel-jellyfish in waters off northern France using GPS loggers equipped with accelerometers that allowed the scientists to observe how the jellyfish orientate their movements with respect to currents. GPS-tracked floats were used to record the local currents. The GPS data showed they were actively swimming counter to the current and the researchers are now asking whether this occurs with other species of jellyfish?

If in fact this "superpower" is possessed by other species, the researchers say it will present a solution to the universal problem of jellyfish blooms. By yetter understanding the blooms it might be possible to predict where and when they will appear, allowing aquaculture farms and others to take protective measures.

"The insights into their behavior and the movements of the ocean helps to explain how jellyfish can form blooms including hundreds to millions of individuals for periods up to several months," said Professor Hays.

It isn’t known how they can "know" how to do this, but it’s possible they could detect current shear or assess the drift using infrasound or the Earth’s magnetic field.

"We now know that jellyfish are not just bags of jelly drifting passively in the oceans," adds Professor Hays. "They are incredibly advanced in their orientation abilities."

There are plans to replicate the work in Tasmania, home to many salmon farms.

The team's research was published in the journal Current Biology

The video below shows one of the jellyfish being tagged.

Source: Deakin University

Wild Rhizostoma Jellyfish

1 comment
Professor Worthington
From: Hyun Myung Date: Tuesday, February 10, 2015 Subject: Policy Debate/Jellyfish Elimination Robotic Swarm
In my experience, the cost will be about 10,000 ~ 15,000 USD per a robot not including all the managing expenses. A1. The cost for one robot is roughly estimated by considering the material and manufacturing costs. You could guess about the costs referring to our published papers. A2. The typical managing expenses includes mobile communication(3G/LTE) fee, robot storage fee (including electricity charges), robot maintenance costs, and the personnel expenses for robot operators. A3. We have already transferred technical know-how related to JEROS to a robotics company and the development for the commercialization is in progress. Thus, we are expected that JEROS will be commercialized in a few years. A4. The required number of robots can be estimated by the coverage rate of JEROS per unit time (e.g., a few hours) and the total area where jellyfish is overpopulated. According to the required number, the budget will be formulated. A5. We have not yet been dealt with the larger species. We endeavor to enhance the speed, the efficiency of jellyfish removal, and the variety of environmental conditions for JEROS operation. Cheers, Hyun