A team of scientists from the Institut de Ciències del Mar (ICM-CSIC) has made a major breakthrough in understanding the biology of the common octopus (Octopus vulgaris) by revealing, for the first time, details of the diet of juvenile octopuses. This discovery, published in Reviews in Fish Biology and Fisheries, has important implications for the conservation of this species and the regulation of invasive species in the Mediterranean.
The research focused on a crucial and little-studied stage of the octopus life cycle: the juvenile phase, which begins when these organisms settle on the seabed after their planktonic period. During this phase, juvenile octopuses exhibit a specialised diet, mainly focused on small crustaceans, with a notable preference for amphipods, including the invasive species Jassa slatteryi. The study highlights that 90% of the stomachs analysed contained remains of this amphipod, indicating a strong preference for this species.
This finding suggests that juvenile octopuses could play a crucial role in regulating this invasive species, which has begun to colonise the Mediterranean. This is particularly important as the ability of octopuses to control populations of invasive species could help maintain the ecological balance of these marine habitats.
Oscar Escolar, lead author of the study, emphasises the importance of this discovery for environmental management: "Thanks to this research, carried out in constant collaboration with the fishing sector, we have been able to reveal for the first time the natural diet of newly settled and juvenile octopuses, which could be of great use in the management of invasive species in the Mediterranean".
The importance of the study lies not only in identifying the diet of juvenile octopuses, but also in the implications for aquaculture and fisheries management. By better understanding the dietary needs of octopuses at all stages of their lives, scientists and fishermen can optimise farming practices and manage octopus populations, a species that is highly valued on the market.
Using advanced molecular techniques, the researchers were able to gain a detailed insight into the diet of juvenile octopuses, including the identification of hydrozoans as the second most abundant group in their diet. Roger Villanueva, coordinator of the study, emphasises the precision achieved by these techniques: "This information would have been difficult to obtain using visual prey identification techniques based on the morphology of the stomach contents, since hydrozoans are composed of 90% water, and given the extremely fast digestion times, it is difficult to identify the remains of these prey".
In addition, the study introduced an innovative juvenile octopus collector, registered as a utility model, which has attracted international interest from research groups. This device allowed extensive sampling over three years in the waters of Vilanova i la Geltrú (Barcelona), providing unprecedented data on the settlement and recruitment of juvenile octopuses.
Looking ahead, ICM-CSIC scientists plan to continue studying the trophic ecology of octopus, focusing on how changes in their diet might affect the microbiome of their digestive tract. This could open up new avenues in biotechnology, marine ecosystem conservation and assessing the impact of climate change.
Reference:
Escolar, O., Fernández-Álvarez, F. Á., & Villanueva, R. (2024). Octopus diet during the settlement period using DNA metabarcoding. Reviews in Fish Biology and Fisheries, 1-19
Related
