Experts from the AN Severtsov Institute for Ecology and Evolution Problems (IPEE), affiliated with the Russian Academy of Sciences, have discovered a defense mechanism in ivy fish (anabas) that identifies inedible objects and ensures that they do not consume them with food. This was reported to socialbites.ca by the Russian Ministry of Education and Science.
The freshwater reservoirs of central Vietnam, where the climbing bass live, are heavily polluted by plastic waste that is then dumped into the sea. However, the climbing bass successfully survives in polluted waters. Scientists decided to find out how often these fish catch polystyrene foam, a heat-insulating material widely used in industry and everyday life, instead of food. It is known that in terms of granule size of expanded polystyrene corresponds to the food pieces preferred by ivy fish.
To do this, they conducted an experiment in which they presented the climbing perch with three options for pellets: food, plastic, and a mix of food and plastic. They recorded how long it took to catch the fish with the help of cameras. The results showed that the climbing bass ate the bait before the plastic, but when the mixture was fed, the fish took up both the bait and the plastic at the same time.
“The climbing perch grasped the plastic particles, mistaking them for food, held them in her mouth for a while, but never swallowed them. Some of the rejected plastic granules are deformed and broken into small pieces. Ekaterina Ganzha, a researcher at IPEE RAS, says this demonstrates that climbing bass has a mechanism for intraoral testing of captured objects, which can evaluate the properties of the captured object due to taste and tactile reception in the oral cavity. , told Gazeta.ru.
According to the authors, intraoral testing of food objects in fish is provided by taste receptors (chemoreceptors) and sensory cells located in the oropharyngeal cavity.
“In our experiment, the fish distinguished the plastic from the food even if there were bits of food on the surface of the plastic. This mechanism contributes to the survival of climbing sea bass in conditions of plastic contamination of inland waters in Vietnam.”
This could mean that other aquatic organisms have similar mechanisms, but scientists believe this hypothesis needs to be tested with further research.