Scientific Name:
Triakis semifasciata
Family:
Triakidae
(Houndsharks)
Found at the Slough:
Salt waterways
Did you know...
Leopardsharks are not harmful to humans.
Leopard sharks are abundant in Elkhorn Slough during spring and summer. These part-time slough residents come into the shallow water to give birth. The adults can be up to 7 feet long, feeding on animals that live in the mud, like the Fat Innkeeper Worm. These sharks are not harmful to humans due to their small teeth and timid nature.
Leopard sharks are generally nocturnal, spending their days near the bottom and becoming more active at night. Low tides in summer are a great time to visit the Reserve as these sharks can often be seen from land- cruising the shallow waters. They are taken occasionally by recreation anglers in the slough.
They are oviviparous giving birth to live young, up to 20 in one litter. The young sharks, like many other fish spend their early days in the warm sheltered bays and tidal creeks of the slough. As they grow, they venture into deeper waters before eventually making their way to the Bay and Ocean.
Sharks in general are well known for their teeth. They have a lifetime supply and are constantly growing new spares. A shark may have anywhere from 5 to 20 rows of teeth. Only the front row of teeth stick up, the others lie flat behind it. With all these teeth, it is surprising that sharks don't chew their food. They use them just to rip and cut food, then swallow it whole.
Sharks also have no bones, thier skeletons are made up of cartilage instead. Cartilage is sturdy like bone, but it has a much lower density. This material keeps sharks relatively lightweight, so they don't sink in the ocean and they don't need an air bladder like other fish.
Sharks have a keen sense of smell and excellent hearing, but they also possess some senses scientists don't fully understand. The ampullae of Lorenzini give the shark electroreception. The ampullae consist of small clusters of electrically sensitive receptor cells positioned under the skin in the shark's head that allow them to seek out fish and other prey hiding on the ocean floor. The shark's lateral line is a set of tubes just under the shark's skin that alerts the shark to any potential prey or predators in the area.
The elasmobranchs (or cartilaginous fishes) of Elkhorn Slough are especially well studied. Background information comes from angling derbies in the late 1940s. More recently, researchers have studied feeding ecology, reproduction and age and growth of slough elasmobranchs. Currently, a team from the Pelagic Shark Research Foundation is monitoring sharks and rays at ESNERR. Check out their program and initial results on their website: http://www.pelagic.org/slough.
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