Human impact on a food source unexpected

RALEIGH, N.C., Aug. 31 (UPI) -- Human impact on a shellfish consumed in the Pacific for thousands of years may have caused the species to actually increase in size, U.S. researchers say.

Scientists at North Carolina State University, in a counterintuitive finding, say the average size of the humped conch, a food source in the Pacific islands for 3,000 years, has increased in spite of -- or even possibly because of -- increased human activity in the area, a university release said Tuesday.

"What we've found indicates that human activity does not necessarily mean that there is going to be a negative impact on a species -- even a species that people relied on as a major food source," Scott Fitzpatrick, associate professor of sociology and anthropology at NC State, said. "The trends we see in the archaeological record in regard to animal remains are not always what one would expect."

Researchers expected the size of the conchs to decrease over time, based on the conventional wisdom that an expanding human population would result in the conchs being harvested before they could achieve their maximum size.

Instead, they say, the average size of the conchs actually increased in conjunction with a growing human population.

Fitzpatrick believes the size increase is likely related to an increase in nutrients in the conch's waters, a result of increased agriculture and other human activities.

"In the big picture," Fitzpatrick says, "this study tells us to focus on the physical evidence and beware of conventional wisdom."