We arrived back in San Diego from our last Great White Shark trip just in time for an “aggressive” hammerhead shark to close a popular La Jolla (San Diego) beach.

According to the San Diego Union Tribune, “A hammerhead shark that circled and followed a group of swimmers and kayakers near La Jolla Shores prompted lifeguards to close a stretch of water to thousands of beachgoers Saturday afternoon.”

A hammerhead shark circles a kayaker near La Jolla Shores Saturday. The shark’s aggressive behavior prompted the beach to close for the remainder of the day and night. — Jimmy Van Evera

Since these hammerhead sharks are not normally “aggressive” towards humans and usually quite shy, I was surprised to hear that one was actually approaching a group of swimmers.

Upon further reading of the article, I found that there was a good reason for the shark to come close to the kayak and the swimmers.  “We each caught a yellowfin, and we always bleed them out to keep them fresher,” said Jimmy Van Evera, who estimated they’d fished for three hours. “We were paddling back in and we saw this hammerhead pop up near our kayaks.” It was about 10 yards away, but ventured closer and closer”

Ok, that explains a lot. Hammerheads, like most sharks love to eat tuna. By bleeding their catch into the water, the fishermen essentially rang the dinner bell for the shark in question. The tuna blood was covering their kayaks and by paddling to shore, the kayak left a scent trail for the shark to follow.  The shark knows what a tuna looks like and once it sees the kayak, is curious to find out what smells like a tuna, but looks like a kayak. These hammerheads are not really a threat to humans, unless they happen to be covered in fish blood.

The headline for this story should have read “Irresponsible fishermen lure shark close to swimmers”, instead of calling the shark aggressive. 

If a human smells food and goes to check it out, is he/she showing aggressive behavior? Since there was tuna blood in the water and sharks are curious to investigate what smells like a tune, but looks totally different, it was probably a good idea for the lifeguards to get the people out of the water.

Personally, if I would hear there is a hammerhead in the water, I’d grab a mask and snorkel, go in and check it out. They are beautiful creatures and, as long as you’re not smelling like fish blood, not a threat to humans.

Cheers,
Martin Graf
CEO Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.