Based on the amount of nitrogen flowing down the Mississippi and Atchafalaya rivers, scientists predict this year’s area of low oxygen in the Gulf of Mexico will reach a size roughly the same as New Jersey.

The area of low oxygen, known as the dead zone, will likely measure between 7,450 and 8,456 square miles, researchers said Thursday. At that size, this year’s dead zone could be one of the largest on record. The largest on record was in 2002 at 8,848 square miles.

“The high water volume flows coupled with nearly triple the nitrogen concentrations in these rivers over the past 50 years from human activities has led to a dramatic increase in the size of the dead zone,” said Gene Turner, the lead dead zone forecast modeler from Louisiana State University.

Urban and Midwest farmland runoff rich in nutrients is blamed for feeding the dead zone every summer. The nutrients from the heartland flow down the Mississippi and spark algae blooms in the Gulf that consume the oxygen in waters off Louisiana, Mississippi and Texas.

The dead zone was first studied in the 1970s. Since then, the zone has grown and scientists warn it could threaten Gulf fisheries, where the largest fleet of fishermen in the Lower 48 states works.

Researchers with the Louisiana Universities Marine Consortium, Louisiana State University, and the University of Michigan made this year’s forecast. The research is funded by the National Oceanic and Atmospheric Administration.

Scientists will measure the size of the dead zone by boat and announce their findings in mid-July.