robotic predator scares fish ~ Oscar and Zebra fish !!

It is  so enchanting looking at fish swimming whether in a pond or in an aquarium.  Fish keeping is a popular hobby which sure would provide one  lot of mental peace and tranquilty.  In Temple tanks, there are generally Guppies, Corp and other local varieties – at  Thirumayilai Kapaleeswarar Tank, there was trouble due to introduction of variety of catfish.

allikkeni thirukulam

The zebrafish (Danio rerio) is a tropical freshwater fish belonging to the minnow family (Cyprinidae) of the order Cypriniformes.  Native to the Himalayan region, it is a popular aquarium fish, frequently sold under the trade name zebra danio. The zebrafish is also an important vertebrate model organism in scientific research. It is particularly notable for its regenerative abilities, and has been modified by researchers to produce several transgenic strains.

Researchers are keen to understand why apple-shaped people, who carry a lot of weight around the stomach, are more susceptible to diabetes and heart disease than their pear-shaped counterparts, who have bigger hips and thighs. An important clue has come from a study of zebrafish, reported in Proceedings of the National Academy of Sciences, showing that a gene called Plexin-D1 plays a key role in controlling where fat is stored and the shaping of fat cells. Earlier human studies comparing the DNA of people with different body shapes had suggested that Plexin-D1 might be involved but had provided little information about the mechanism.

There is another popular fish ‘Oscar’ nothing to do with Academy awards though ! - Astronotus ocellatus is a species of fish from the cichlid family known under a variety of common names including oscar, tiger oscar, velvet cichlid, or marble cichlid.  From its native  South America, the species was introduced to other areas, including China, Australia, and the United States. It is considered a popular aquarium fish in the U.S. 

I have  posted many a times on Rajnikant starrer, Shankar directed blockbuster‘Enthiran’ - Dr Vaseegaran, a scientist working on alternative intelligence developing  a humanoid  robot  which gets rejected by sinister designs.   There have been ‘robot fish’ that are charming pets and a couple of years ago, Massachusetts Institute of Technology (MIT) unveiled a robot fish that it claims can change direction almost as fast as the real thing. The fish – or “autonomous soft robot” as it’s described by MIT – could perform escape manoeuvres through rapid convulsions of its body, powered by carbon dioxide released from a canister in its abdomen. “The fish was designed to explore performance capabilities, not long-term operation,” said Marchese in MIT’s announcement of the research.  There was another robot fish designed by Koreans that cleans clothes.   It was a new concept for washing machines - using robot fish. Each fish uses a built in camera to identify dirt particles, and then swims over to suck them up.

Now comes the news of ‘Ultra-realistic Robotic Predator’ scaring fish.  New York University  engineers have developed a robotic predator so realistic that it causes fear among real fish. The study has significant implications for scientific research involving animals.  The predator at hand is a red tiger oscar fish. It might seem small, but not in the eyes of a zebrafish. The latter is often used in behavioural studies thanks to its versatility. However, there are a number of issues with using live animals to conduct research, mainly their unpredictable nature. That’s one of the reasons Maurizio Porfiri, an NYU professor of mechanical and aerospace engineering, creates bio-inspired robots.

He says there are a number of advantages to using robots in animal behavior studies, including consistency and repeatability (the researchers are able to control their robotic predator as opposed to relying on a live one).  Porfiri and his team divided an experimental tank into three compartments; one was empty, the second contained live zebra fish and the final one featured three different experimental stimuli. The zebra fish exposed to real oscar fish and those that spent time with the robotic models exhibited similar behavior. In fact, the fish tended to avoid the robot more than the real oscar fish.

“Avoidance isn’t the only way we can tell a zebrafish is scared,” Porfiri told NYU. “When these fish are afraid, they also swim differently, and we were surprised to find that the robotic fish could produce an even stronger fear-related response than the actual live predator.”  In contrast, the zebrafish exhibited little fear towards animated images of the predator. “The oscar fish is a known zebrafish predator, but it’s not the most threatening one out there,” said Porfiri. “We chose a predator that could be relied upon to scare the zebrafish, but not to the point of complete avoidance that would mask what we were trying to uncover.”

The study proved to the team that it’s possible to induce fear in an animal using a robot. Their findings will be released in the June issue of the Zebrafish journal.  Source : http://engineering.nyu.edu/

With regards – S. Sampathkumar

22^nd May 2015.