Molecular approach indicates consumption of jellyfish by commercially important fish species in a coastal Mediterranean lagoon

Until recently, jellyfish have been ignored as an important source of food, due to their low nutritional value. Here, quantitative PCR was used to detect and quantify the DNA of the jellyfish Aurelia coerulea in the gut contents of commercially important fish species from the Thau Lagoon. Individuals from five fish species were collected during two different periods: the bloom period, when the pelagic stages of A. coerulea are abundant, and the post-bloom period, when only the benthic stage – polyps – is present in the lagoon. The DNA of A. coerulea was detected in the guts of 41.9% of the fish analysed, belonging to four different species. The eel Anguilla anguilla and the seabream Sparus aurata were important jellyfish consumers during the bloom and post-bloom periods, respectively. These results provide new insights on the potential control of jellyfish populations and on jellyfish importance as a food source for exploited fishes. •DNA of the jellyfish Aurelia coerulea was detected by qPCR in the guts of four commercially important fish species.•All the individuals of European eel analysed had jellyfish DNA in their guts.•Gilthead Sea bream likely indirectly consumed jellyfish polyps, by preying on their settling substrates (bivalves).•Jellyfish might be a non-negligible important food source for commercially exploited fish species.