Species → Scalloped Hammerhead Shark
Scalloped Hammerhead Shark
Sphyrna lewini
What if it disappeared?
Impact HighAlong the U.S. East Coast, the gradual disappearance of large predatory sharks coincided with an explosion of the cownose ray, one of their usual prey — which then wiped out the scallop population it feeds on, closing a century-old fishery.
DocumentedDetail
Myers, R.A., Baum, J.K., Shepherd, T.D., Powers, S.P. et Peterson, C.H. (2007). Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean. Science, 315(5820), 1846–1850.
Analyzing decades of fishing data along the U.S. East Coast, the authors show that the collapse of eleven large shark species (including the scalloped hammerhead) let mesopredators like the cownose ray proliferate unchecked. This ray began consuming enough scallops to shut down a fishery more than a century old in North Carolina.
How many other comparable cascades remain to be documented for the many other prey these sharks once fed on remains largely unknown.
InsufficientDetail
Myers et al. only tracked the effect on the cownose ray and scallop in detail — an emblematic case, not a complete inventory of everything the disappearance of large sharks changes in a coastal ecosystem.
Documentation
-
IUCN Red List — Sphyrna lewini, statut de conservation
Accessed August 7, 2026
-
Myers et al. (2007) — Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean, Science
Accessed August 7, 2026
Last verified: August 7, 2026