GAINESVILLE, Fla. --- The migration of mature female tiger sharks during late summer and fall to the main Hawaiian Islands, presumably to give birth, could provide insight into attacks in that area, according to a University of Florida scientist.
In a new seven-year study, researchers from UF and the University of Hawaii used new techniques to analyze the predators' movements in the Hawaiian archipelago, where recent shark incidents have gained international attention, including a fatal attack in August. The study revealed different patterns between males and females less inter-island movement was seen in males, while about 25 percent of mature females moved from the remote French Frigate Shoals atoll to the main Hawaiian Islands during late summer and early fall. The peer-reviewed authors' manuscript is available online and tentatively scheduled to appear in the November print issue of Ecology.
"We have previously analyzed data to see which sharks are hanging around shark tours with cage divers on Oahu, and one of the things we noticed was that you'd get a spike in how many tiger sharks are seen in October, which would match our predicted model that you're having an influx of big, pregnant females coming from the northwestern Hawaiian Islands," said Yannis Papastamatiou, a marine biologist in the division of ichthyology at the Florida Museum of Natural History on the UF campus. "There even tends to be a spike in the number of shark bites that occur during that season."
The current study focused on migration patterns and not human-shark interactions, but data from the International Shark Attack File housed at the Florida Museum show Hawaii had 10 reported attacks in 2012. This year eight reported attacks have occurred, and the August fatality was the state's first since 2004. Since 1926, the highest numbers of reported attacks in Hawaii occurred in October, November and December.
"We knew tiger sharks had fairly c
|Contact: Yannis Papastamatiou|
University of Florida