Maine’s two Republican senators are asking for a full bottom survey of Cobscook Bay following the deaths of a number of fishermen in the region in the past two years.

In their request to Jane Lubchenco, administrator of the National Oceanic and Atmospheric Administration, Sens. Olympia Snowe and Susan Collins said a survey would help area fishermen navigate and use their fishing gear more safely in the area.

Tides in Cobscook Bay, the easternmost point of the United States, range more than 20 feet, among the highest on earth. The tides cause powerful currents and changing sea conditions, the senators noted.

Seven fishermen have died in the bay since 2008 in sinkings many fishermen blame on inadequate charts, the senators said.

The last bottom survey was in 1899.