Acute aquatic toxicity studies of Gulf of Mexico water samples collected following the Deepwater Horizon incident (May 12, 2010 to December 11, 2010).

•Water samples were taken at 44 sites following the Deepwater Horizon incident.•Water accommodated fractions (WAFs) and oil-in-water dispersions (OWDs) were tested.•Mysids were generally more sensitive than inland silversides.•Most mortality observed occurred in samples collected before the well was capped.