Diet and diel feeding periodicity of juvenile scalloped hammerhead sharks, Sphyrna lewini, in Kane'ohe Bay, O'ahu, Hawai'i

I studied diet and feeding habits in juvenile scalloped hammerhead sharks in Kane'ohe Bay, Hawai'i, from August 1995 to May 1998. The most common prey items were a single species of alpheid shrimp and two species of goby. Benthic surveys indicated that the shrimp and gobies are the most abundant benthic megafauna in Kane'ohe Bay. Sharks had small amounts of food in their stomachs ( median = 0.22% of body weight), and sharks with open umbilical scars were more likely to have an empty stomach than sharks with healed umbilical scars. There was a significant diel change in the amount of food in the stomach. Analysis of stage of digestion data and the frequency of occurrence of empty stomachs also indicated that sharks fed more at night than during the day. A number of other factors that might influence diet and feeding were also investigated, including the effect of area, sex, year, season, and proximity to the patch reefs. Season and year had significant effects on the amount of food in sharks' stomachs, but sex and proximity to the patch reef did not.