The report was done for Kenneth Feinberg, who is administering the compensation fund for victims of the spill, The New York Times said. Feinberg plans to release it Wednesday.
Some oyster beds could take much longer to recover, the report said.
The explosion on BP's Deepwater Horizon oil rig in April 2010 was followed by a massive blowout that sent millions of barrels of oil into the Gulf.
Feinberg's report is to include an overall plan for distributing the $20 billion compensation fund.
Wes Tunnell, a marine biologist at the Harte Research Institute in Corpus Christi, Texas, in a 39-page report on fisheries in the Gulf, predicted that catches of most fish and shellfish would be back this year to the levels reached before the spill. But he said some areas might take longer to recover, especially the oyster beds most affected by the spill.
The states of Louisiana and Mississippi filed complaints Tuesday with the judge in New Orleans in charge of litigation arising from the spill. They charge that Feinberg is too closely tied to BP to be impartial.