The BP oil spill is one of the biggest oil spills in U.S. history, and a new study out of Texas A&M University-Corpus Christi says the catastrophe did even more damage than previously reported.

"Severe degradation," said Paul Montagna of TAMUCC's Harte Research Institute. "We say losses of up to 30-50 percent of diversity and abundance. A huge decrease in organisms that should be there."

The study, conducted by the Harte Research Institute, is the first of its kind to assess the deep sea following the 87-day spill. Researchers say much of the focus was put on the surface effects of the oil spill, and that they were surprised to find much of the oil never left the deep sea.

They added that the recovery in the vicinity of the Deepwater Horizon blowout will take decades or longer.