Effects on different populations consist of increased mortality or as sub-lethal impairment on the organisms' ability to forage, reproduce and avoid predators.[150] In 2013, it was reported that dolphins and other marine life continued to die in record numbers with infant dolphins dying at six times the normal rate,[154] and half the dolphins examined in a December 2013 study were seriously ill or dying. BP said the report was "inconclusive as to any causation associated with the spill."[155][156]