We have fewer jellyfish also thanks to turtles

The years when swimming became impossible due to the abundance of jellyfish in the water seem far away. They are still visible, and some scientists link the phenomenon to the increase in turtles, which are avid jellyfish eaters. 

Jellyfish can concentrate on a given coast due to currents, wind, temperature, and food availability: this is why their presence is highly variable. A 2025 study , with related scientific monitoring, shows that the main areas where blooms are observed are mainly the Tyrrhenian Sea, the Ligurian Sea, and the upper Adriatic . The MeteoMeduse database , for example, shows that between August 7 and September 6, only two sightings were recorded in its database: a Rhizostoma pulmo in Tuscany and a Cotylorhiza tuberculata in the upper Adriatic.

But why do turtles eat jellyfish? There are several reasons:

• They are abundant: in some areas they can form large concentrations.
• They are easy to catch: They move more slowly than turtles. 
• They provide energy: Although they are mostly made up of water, they contain proteins and other nutrients.
• The leatherback turtle has a peculiar mouth, with “spiny”-like structures that help hold the jellyfish while it expels water.

And here's one important thing: the venom from the tentacles doesn't usually stop the turtle from eating them . The skin of the mouth and esophagus is quite resistant to the jellyfish's stinging cells. Unfortunately, the only real problem is that turtles frequently confuse jellyfish with transparent or semi-transparent plastic bags, which can float and sway in the current just like a jellyfish. Many jellyfish are nearly transparent, as are the bags . Some plastics have whitish, blue, or translucent hues that resemble those of jellyfish , and if an animal has learned that something that floats and moves that way can be prey, it can be drawn to tasting it.

A simple plastic bag can cause serious harm to turtles when digested. For example:

• Bowel obstruction: Plastic can lodge in your stomach or intestines and prevent food from passing normally.
• Internal injuries: Pieces or edges of the plastic can irritate or even perforate the digestive tract.
• False satiety: The turtle may feel full even though it has ingested something that provides it with practically no nourishment. Consequently, it can eat less and get weaker.
• Plastic accumulation: If you continue to ingest it, several fragments may accumulate in your digestive tract, forming a mass.
• Inflammation and infections: An obstruction or injury to the intestine can cause serious complications.
• Death: In the most severe cases, obstruction, perforation or debilitation can lead to the death of the animal.

Read also:

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