VIDEO: Hammerhead shark hunts blacktips in Florida's shallows during annual migration

Kimberly Miller
Palm Beach Post
The hammerhead sharks in the drone videos that show them chasing blacktips were at least twice the size of the blacktip sharks, making them about 12 feet long. They can get as big as 18 feet long. Despite their large size, they are often found in relatively shallow waters that are likely an important area for their feeding.

The annual migration of blacktip sharks is underway in South Florida with the shadowy predators flirting with Palm Beach County's coastline.  

But a video posted Monday on social media by the Florida Atlantic University Elasmobranch Lab shows how blacktips are both predator and prey as a hammerhead shark pursues them in shallow waters off John D. MacArthur Beach State Park in North Palm Beach. 

FAU researchers published a study last year that found blacktips may hug the shoreline as a way to evade becoming a meal for the less agile hammerhead. 

FAU biological sciences professor Stephen Kajiura said Monday's video isn't the best example of the shallow water pursuit because it doesn't show the proximity to shore, but three videos included with the 2020 study clearly show how close the blacktips came to the beach to elude hungry hammerheads. 

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While previous studies have shown that young sharks use shallow water to avoid being eaten, "no documentation was available to show that large adult sharks actively swim into shallower waters to avoid predation," the FAU study said.

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When a hammerhead's dorsal fin and upper lobe of its tail fin breach the surface in shallow water, it hurts the hammerhead's ability to maneuver. The blacktip shark, on the other hand, can stay submerged in shallow water, making it more nimble. 

Blacktip sharks begin plying the waters of Southeast Florida at the end of January with the highest concentrations appearing in February. Their voyage often makes national news when captured in aerial footage. The sight of hundreds of sharks languidly cruising the beach can be unnerving and awe-inspiring.

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Kajiura began tracking the blacktips' yearly sojourn along South Florida's coastline a decade ago by meticulously counting each shark in photos taken during flights from Boca Raton to Jupiter.

Kmiller@pbpost.com

@Kmillerweather