Cunning bar jacks use sharks to sneak up on prey
It turns out that the bar jack (Caranx crysos) is a small yet very cunning fish. Predatory fish use sharks to hide their presence from potential prey, reports the journal "Ecology." Videos taken by divers and remotely operated underwater vehicles revealed 34 examples of bar jacks using this hunting strategy.
Scientists from the University of Edinburgh and Italian research institutions observed the unusual behavior of bar jacks (Caranx crysos) in the Mediterranean Sea. These small predatory fish use sharks, specifically the sandbar sharks (Carcharhinus plumbeus), as cover while hunting smaller fish species.
The research published in "Ecology" revealed that bar jacks follow sharks for about 30 seconds before launching an attack on their prey. Videos taken off the coast of the Italian island of Lampione showed 34 instances of this behavior.
Bar jacks surprise their prey
Analysis of the video footage suggests that bar jacks, which usually hunt in small groups, are more likely to surprise their prey and have a higher chance of success if they follow sharks. When bar jacks hid behind a shark, the prey noticed their approach only in about 10 percent of cases.
According to scientists, following sharks not only increases the hunting success of bar jacks but also protects them from other predators. Additionally, thanks to the water movement caused by sharks, bar jacks conserve energy.
According to Professor Fabio Badalamenti from the University of Edinburgh and CNR-IAS in Palermo, the research shows that relationships between species play a role in developing alternative hunting behaviours in marine environments, which broadens our understanding of marine biodiversity and highlights the importance of conserving apex predators like sharks.
Excessive shark fishing
Dr. Carlo Cattano from Stazione Zoologica Anton Dohrn points out the ecological significance of shark aggregations, which can impact the structure and functioning of ecosystems.
Lampione Island is one of the two known places in the Mediterranean Sea where sandbar shark aggregations occur. The expert explained that the continued decrease in large shark populations as a result of overfishing could put these groups at risk and might also have harmful consequences for other species.
