Observations on the Food Habits of Leopard Sharks (Triakis semifasciata) and Brown Smoothhounds (Mustelus henlei)

Russo, Ronald

This study examined and compared the stomach contents of brown smoothhound sharks and leopard sharks from both Tomales and San Francisco Bays. The stomach contents of the smoothhound sharks indicated a propensity for feeding in intertidal areas- a characteristic not evidenced by the stomach contents of the leopard sharks. Information on the food habits of M. henlei and T. esmifasciata was collected from May, 1970 through June 1973. The stomach contents of 45 leopard sharks and 25 smoothhounds from San Francisco Bay, California revealed similar food habits as are found in Tomales Bay, California. Of the smoothhounds examined, 39% contained shrimp, 35% crabs, and 22% fish. Of the leopard sharks examined, 17% contained shrimp, 16% crabs, and 19% fish. The occurrence of a significant quantity of shore crabs (Hemigrapsus oregonensis) in smoothhounds indicates a definite intertidal feeding habit, which is not evidenced by the quality of food in leopard sharks. In addition, 17% of the leopard sharks contained fish eggs, 9% clam necks, and 19% contained worms. While shrimp, crabs and fish were important items in the diets of both sharks, leopards are distinguished by the appearance of clam necks, worms, and fish eggs in significant quantities. The occurrence of benthic forms like Upogebia, Callianasa and Urechis and various clam necks indicates a shoveling or burrowing habit by leopard sharks in capturing prey. This idea is supported by findings on concs of chlorinated hydrocarbons in leopard and brown smoothhound liver tissues.

Observations on the Food Habits of Leopard Sharks (Triakis semifasciata) and Brown Smoothhounds (Mustelus henlei)

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