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Dive Dry with Dr. Bill

#705: Leopards Don't Scare Me... Or You!

Sharks were spotted in the dive park this weekend. No, not great whites.. haven't seen one of those there since last July. These sharks might be considered wimps since they usually flee when they hear bubbles from a regulator. However, it was interesting that at least two groups of divers saw this species in the park.

In all the years and over the thousands of dives I've done there, I only remember seeing leopard sharks (Triakis semifasciata) twice. Both times I was at the harbor end of the park and sensed something coming from behind me. Thanks to that premonition, I was able to have my camera ready as a leopard shark swam past my shoulder and kept on going.

Leopard sharks are often very common in our waters at places like Shark Alley, Frog Rock, Bird Rock and Indian Rock. They usually appear during the warmer months rather than this late in the year. I remember kayaking near Frog Rock with my sisters when we encountered a number of them. I told the girls to jump in the water and swim with them like I was doing, but they didn't accept the invitation!

Leopard sharks tend to be small, reaching a maximum length of about seven feet and just over 40 pounds. Heck, they're not even close to my weight class. Their bodies are a bit skinny and have a series of dark saddles on the back often with dark spots along the side. Their range extends from Washington state to Mazatlan, Mexico, and the Sea of Cortez.

This species exhibits short distance migration, often entering shallow water such as bays as waters warm in the spring then leaving these habitats as water cools in the fall. Down in La Jolla, large groups of leopard sharks may be seen year-round. Occasionally these sharks have been known to make longer swims as from Catalina to the SoCal mainland. However there does not seem to be a lot of gene flow between populations, suggesting a level of isolation.

Leopard sharks apparently mate shortly after the live young (as many as 37 at once) are expelled by the female. I guess they like to stay bare finned and pregnant. Mating was observed by a researcher down in La Jolla. A group of sharks swam together in a somewhat circular pattern. Occasionally one would turn on its side, exposing its lighter belly. The male then wrapped its body around the female and the two rolled around together for about 15 seconds.

Leopard sharks are generally quite harmless to human beings, and tend to shy away from divers. They feed near the bottom on flish, crabs, worms, squid and octopus with a little seaweed or sea grass salad to keep the diet healthy. In turn they may be eaten by larger sharks and by sea lions.

Years ago when I was diving the Great Barrier Reef off Cairns, Australia, I was surprised to run into another species of leopard shark, Stegostoma fasciatum. This species of carpet shark is probably more commonly known as the zebra shark because the young have a dark body with light stripes. When they are older the stripes disappear and the body is full of spots like a leopard. I've also seen this shark elsewhere in tropical Indo-Pacific waters, most recently while diving in Palau.

While diving the GBR, I was on a liveaboard near the outer reef. It was here that I decided I wanted to learn to take underwater video as I watched a turtle chowing down on algae in front of my face. We did several night dives as well. On one I was getting ready to do my giant stride off the stern of the boat. As I jumped, I saw a leopard shark swim out from under the boat. I landed right on its back like a cowboy jumping on a horse from a high rock. The poor shark freaked out and hightailed it to safer hunting grounds.

© 2016 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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Leopard sharks at Indian Rock and Bird Rock, Catalina Island.

This document maintained by Dr. Bill Bushing.
Material and images © 2016 Star Thrower Educational Multimedia