CRITTER: Meet mano the Sandbar Shark

This eight-foot-long shark is one of the most-common sharks in Hawai‘i but is rarely seen by divers or swimmers. This is a deep-water species that normally lives offshore in deep blue water, but near the islands of Ni‘ihau and Lehua divers see them often in shallow water. The sandbar shark is easy to recognize by its large, pointed, first dorsal fin that is far up on its body, which makes it look like a military fighter jet when it zooms by in the deep blue water.

The first time I ever saw one of these sharks was scuba diving off Ni‘ihau years ago, and the event was quite scary. I was not sure what type of shark it was, and there were two of them that I easily recognized as being gravid (pregnant). I was diving by myself on a shallow ledge near a deep-water cliff and both of these female sharks seemed agitated by the way they were swimming, with jerky-type movements. I wasn’t quite sure what to do so I decided to leave the area when one of the 300 pound females charged directly at me while I was shooting video. It came straight at me very quickly and just before it ran into the video camera it turned away and went off into the deep blue. A few minutes later the second female did the same thing. It charged the camera and turned away only a foot before hitting me and the video camera. WOW! I have never been bothered by large sharks before, and I have dove with hundreds of them, but this was quite an adrenaline rush.

After both female sandbar sharks charged me they settled down and were quite mellow, and even allowed me to get close-up movies of them for about 15 minutes. I can only assume that they were about ready to give birth and just wanted to make sure that I was not some kind of predator that would be dangerous to their babies. This shark species rarely comes in contact with divers, and we now know they only come into shallow water to have their babies.

On another dive trip, we went out of Hale‘iwa, O‘ahu with shark expert Ocean Ramsey to free dive with a whole school of sandbar sharks she had found several miles offshore in the open ocean! When we got to the spot she had found them previously there was nothing there but crystal-clear, deep-blue water. I jumped in the sea with my video camera and the boat captain revved up the engines a few times. While looking down into the deep blue water I started to see some shapes materialize, and within a few minutes, we were surrounded by 12 large sandbar sharks zooming in all directions around us! It was like being in deep space with 12 spaceships circling you. We had fun diving down and interacting with the shark school and shooting video, then after about 10 minutes the sharks disappeared back into the depths.

After doing some research we found out that the location where we swam with the school of sandbar sharks used to be a favorite spot for crab fishermen. They dropped down crab traps to the sea floor over 400 feet deep and the traps were filled with dead fish. When the boats showed up to pull up the crab traps the sandbar sharks also showed up to feed on the dead fish the crabbers threw back into the water. When the sharks heard our boat engine they came up from the deep to see if we had some lunch for them!

You can see mano the sandbar shark in action in my movie “The World’s Guide To Hawaiian Reef Fish” up on my underwater educational web at www.underwater2web.com.

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Terry Lilley is a marine biologist living in Hanalei and co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai‘i go to www.reefguardianshawaii.org.