A new study of great white sharks in Australia found that the sharks prey on bottom feeding species much more than previously thought.
“Within the sharks’ stomachs we found remains from a variety of fish species that typically live on the seafloor or buried in the sand. This indicates the sharks must spend a good portion of their time foraging just above the seabed,” said lead author Richard Grainger, a Ph.D. candidate at the Charles Perkins Centre and School of Life and Environmental Sciences at the University of Sydney. “The stereotype of a shark’s dorsal fin above the surface as it hunts is probably not a very accurate picture.”
The study examined the stomach contents of 40 juvenile white sharks caught in the NSW Shark Meshing Program. Along with bony fish including eels, whiting, mullet and wrasses, the researchers found that rays were also an important dietary component, including small bottom-dwelling stingrays and electric rays.
The study found that based on abundance, the sharks’ diet relied mostly on:
- Pelagic, or mid-water ocean swimming fish, such as Australian salmon: 32.2%
- Bottom-dwelling fish, such as stargazers, sole or flathead: 17.4%
- Reef fish, such as eastern blue gropers: 5.0%
- Batoid fish, such as stingrays: 14.9%
“This evidence matches data we have from tagging white sharks that shows them spending a lot of time many meters below the surface,” Grainger said.
The results, which were published in the latest issue of Frontiers in Marine Science, can help determining the sharks’ feeding and migratory habits.
“Understanding the nutritional goals of these cryptic predators and how these relate to migration patterns will give insights into what drives human-shark conflict and how we can best protect this species,” said Dr. Gabriel Machovsky-Capuska, an adjunct Senior Research Fellow at the Charles Perkins Centre and a co-author of the study.