A fin above water isn’t a shark on the hunt
A more scientific opening scene to the movie Jaws would look wildly different, as recent research has shown great white sharks spend more time feeding close to the seabed than previously thought.
“The stereotype of a shark’s dorsal fin above the surface as it hunts is probably not a very accurate picture,” said University of Sydney PhD candidate and lead author of the study, Richard Grainger.
Grainger and his team are the first to run a study of this aspect of the dietary habits of great white sharks. By looking at the stomach contents of 40 young great white sharks, the researchers were able to identify different types of prey and, knowing the habitats of the prey, could pinpoint where the sharks spent most of their time hunting.
“White sharks have a varied diet,” said Dr Gabriel Machovsky-Capuska, a co-author of the study. “As well as east Australian salmon, we found evidence of other bony fish including eels, whiting, mullet and wrasses. We found that rays were also an important dietary component, including small bottom-dwelling stingrays and electric rays.”
The only mammal found in the sharks’ stomachs was dolphin. It’s likely that the hunting of bigger prey, including other sharks, would not happen until the great white sharks have grown to 2.2 metres long, explains Grainger. The research also showed that the larger the shark, the higher the fat content in their diet.
To review the great white sharks’ diets, the researchers had to collect stomachs from deceased animals. These were caught in the New South Wales Shark Meshing Program, which is designed to prevent interactions between humans and sharks on 51 Australian beaches.
The results of the study will help in the protection of the species, as well as in managing its relationship with humans.