Constant Indian attacks compounded the problem still more, making it all but impossible for the English to return safely after taking a boat out into the river.
The sturgeon fishery may have been affected by a prolonged period of severe drought, too, Balazik said, describing a dramatic increase in the salinity of the James that may have drawn the population far upstream from Jamestown Island.
"It's possible that instead of stopping here they went right by the island when the salt wedge moved," he said.
"And if that's the case the colonists would never have seen them."
Find more stories about Hampton Roads history at dailypress.com/history and Facebook.com/hrhistory.
Want to go?
James Fort archaeological site
Where: Historic Jamestowne, located on Jamestown Island at the west end of the Colonial Parkway
When: 8:30 a.m.-4:30 p.m. daily, with public archaeology conducted on weekdays, weather permitting
Cost: $14 adults, children 15 and under free (includes admission to Jamestown Visitor Center, Historic Jamestowne sites and Nathalie P. and Alan M. Voorhees Archaerium)
Information: 757-856-1259; 757-229-4997 Ext. 100 or http://www.historicjamestown.org